Spectroscopy Infrared Spectroscopy Introduction n Spectroscopy is an
![Spectroscopy Infrared Spectroscopy Spectroscopy Infrared Spectroscopy](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-1.jpg)
![Introduction n Spectroscopy is an analytical technique which helps determine structure n It destroys Introduction n Spectroscopy is an analytical technique which helps determine structure n It destroys](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-2.jpg)
![Electromagnetic Spectrum n Examples: X rays, microwaves, radio waves, visible light, IR, and UV Electromagnetic Spectrum n Examples: X rays, microwaves, radio waves, visible light, IR, and UV](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-3.jpg)
![The Electromagnetic Spectrum High X-ray Frequency Energy UV uv 200 nm 2020/11/22 IR visible The Electromagnetic Spectrum High X-ray Frequency Energy UV uv 200 nm 2020/11/22 IR visible](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-4.jpg)
![Energy Transitions Table 1. Types of energy transitions of the electromagnetic spectrum Region of Energy Transitions Table 1. Types of energy transitions of the electromagnetic spectrum Region of](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-5.jpg)
![The Spectrum and Molecular Effects => 2020/11/22 6 The Spectrum and Molecular Effects => 2020/11/22 6](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-6.jpg)
![The IR Region n Just below red in the visible region n Wavelengths usually The IR Region n Just below red in the visible region n Wavelengths usually](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-7.jpg)
![Molecular Vibrations n Light is absorbed when radiation frequency = frequency of vibration in Molecular Vibrations n Light is absorbed when radiation frequency = frequency of vibration in](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-8.jpg)
![IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-9.jpg)
![Interpretation n Looking for presence/absence of functional groups n Correlation tables n A polar Interpretation n Looking for presence/absence of functional groups n Correlation tables n A polar](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-10.jpg)
![Carbon-Carbon Bond Stretching n Stronger bonds absorb at higher frequencies: n C-C 1200 cm-1 Carbon-Carbon Bond Stretching n Stronger bonds absorb at higher frequencies: n C-C 1200 cm-1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-11.jpg)
![Carbon-Hydrogen Stretching n Bonds with more s character absorb at a higher frequency sp Carbon-Hydrogen Stretching n Bonds with more s character absorb at a higher frequency sp](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-12.jpg)
![An Alkane IR Spectrum 2020/11/22 13 An Alkane IR Spectrum 2020/11/22 13](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-13.jpg)
![An Alkene IR Spectrum 2020/11/22 14 An Alkene IR Spectrum 2020/11/22 14](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-14.jpg)
![An Alkyne IR Spectrum 2020/11/22 15 An Alkyne IR Spectrum 2020/11/22 15](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-15.jpg)
![O-H and N-H Stretching n Both of these occur around 3300 cm-1, but they O-H and N-H Stretching n Both of these occur around 3300 cm-1, but they](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-16.jpg)
![An Alcohol IR Spectrum 2020/11/22 17 An Alcohol IR Spectrum 2020/11/22 17](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-17.jpg)
![An Amine IR Spectrum 2020/11/22 18 An Amine IR Spectrum 2020/11/22 18](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-18.jpg)
![Carbonyl Stretching n The C=O bond of simple ketones, aldehydes, and carboxylic acids absorb Carbonyl Stretching n The C=O bond of simple ketones, aldehydes, and carboxylic acids absorb](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-19.jpg)
![A Ketone IR Spectrum 2020/11/22 20 A Ketone IR Spectrum 2020/11/22 20](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-20.jpg)
![An Aldehyde IR Spectrum 2020/11/22 21 An Aldehyde IR Spectrum 2020/11/22 21](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-21.jpg)
![O-H Stretch of a Carboxylic Acid This O-H absorbs broadly, 2500 -3500 cm-1, due O-H Stretch of a Carboxylic Acid This O-H absorbs broadly, 2500 -3500 cm-1, due](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-22.jpg)
![Variations in C=O Absorption n Conjugation of C=O with C=C lowers the stretching frequency Variations in C=O Absorption n Conjugation of C=O with C=C lowers the stretching frequency](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-23.jpg)
![An Amide IR Spectrum 2020/11/22 24 An Amide IR Spectrum 2020/11/22 24](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-24.jpg)
![Carbon - Nitrogen Stretching n C - N absorbs around 1200 cm-1 n C Carbon - Nitrogen Stretching n C - N absorbs around 1200 cm-1 n C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-25.jpg)
![A Nitrile IR Spectrum 2020/11/22 26 A Nitrile IR Spectrum 2020/11/22 26](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-26.jpg)
![Summary of IR Absorptions 2020/11/22 27 Summary of IR Absorptions 2020/11/22 27](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-27.jpg)
![Strengths and Limitations n IR alone cannot determine a structure n Some signals may Strengths and Limitations n IR alone cannot determine a structure n Some signals may](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-28.jpg)
![Infrared Regions Region wavelength wavenumber frequency (mm) (cm-1) (Hz) Near Middle Far Most used Infrared Regions Region wavelength wavenumber frequency (mm) (cm-1) (Hz) Near Middle Far Most used](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-29.jpg)
![IR Application Near IR: 770 ~ 2500 nm 1. Using photometers or spectrophotometer similar IR Application Near IR: 770 ~ 2500 nm 1. Using photometers or spectrophotometer similar](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-30.jpg)
![IR Application Mid-IR: 1. Used largely for qualitative organic analysis and structural determination based IR Application Mid-IR: 1. Used largely for qualitative organic analysis and structural determination based](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-31.jpg)
![IR Sources n An inert solid heated btw 1500 ~ 2000 k, The max IR Sources n An inert solid heated btw 1500 ~ 2000 k, The max](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-32.jpg)
![Types of Instruments for IR n Dispersive grating photometers: used for qualitative work n Types of Instruments for IR n Dispersive grating photometers: used for qualitative work n](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-33.jpg)
![IR Absorption Region λ= 2. 5 ~ 15 mm (10 -4 cm = 1 IR Absorption Region λ= 2. 5 ~ 15 mm (10 -4 cm = 1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-34.jpg)
![Theoretical Introduction ΔE = h. ν = h c /λ = h c � Theoretical Introduction ΔE = h. ν = h c /λ = h c �](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-35.jpg)
![IR Absorption Process n A Quantized Process: n Only selected frequencies (energies) of infrared IR Absorption Process n A Quantized Process: n Only selected frequencies (energies) of infrared](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-36.jpg)
![IR Application n Infrared spectrum can be a fingerprint used for identification. n Infrared IR Application n Infrared spectrum can be a fingerprint used for identification. n Infrared](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-37.jpg)
![Absorption UV example Transmittance: T = I/Io Absorbance: A = Log Io/I if no Absorption UV example Transmittance: T = I/Io Absorbance: A = Log Io/I if no](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-38.jpg)
![An Infrared Spectrum 2020/11/22 39 An Infrared Spectrum 2020/11/22 39](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-39.jpg)
![IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-40.jpg)
![Vibration Modes Symmetric Stretch Asymmetric Stretch Symmetric Bend 2020/11/22 41 Vibration Modes Symmetric Stretch Asymmetric Stretch Symmetric Bend 2020/11/22 41](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-41.jpg)
![Vibration Modes of CH 2 Group n Gas Phase IR Spectrum of Formaldehyde, H Vibration Modes of CH 2 Group n Gas Phase IR Spectrum of Formaldehyde, H](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-42.jpg)
![Vibration Modes Sym. Stretching (~ 2853) Asym. Stretching (~ 2926) Scissoring (~ 1450) Rocking Vibration Modes Sym. Stretching (~ 2853) Asym. Stretching (~ 2926) Scissoring (~ 1450) Rocking](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-43.jpg)
![Basic Principle As for any harmonic oscillator, the energy of bond vibration: Eosc h Basic Principle As for any harmonic oscillator, the energy of bond vibration: Eosc h](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-44.jpg)
![Basic Principle The natural frequency of the oscillation νosc = ½ . √k / Basic Principle The natural frequency of the oscillation νosc = ½ . √k /](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-45.jpg)
![Basic Principle From SchrÖdiger Equation: Evib = h νosc (n + 1/2) vibration quantum Basic Principle From SchrÖdiger Equation: Evib = h νosc (n + 1/2) vibration quantum](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-46.jpg)
![Basic Principle The frequency of radiation, ν vibrational frequency, νosc E radiation = h Basic Principle The frequency of radiation, ν vibrational frequency, νosc E radiation = h](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-47.jpg)
![Basic Principle νosc = 1/2 . √k / m m = m 1. m Basic Principle νosc = 1/2 . √k / m m = m 1. m](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-48.jpg)
![Example Calculate the wavenumber and wavelength of the fundamental frequency peak due to the Example Calculate the wavenumber and wavelength of the fundamental frequency peak due to the](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-49.jpg)
![Example �(cm-1) = E vib / h c = 1 / 2 c. √k Example �(cm-1) = E vib / h c = 1 / 2 c. √k](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-50.jpg)
![Force Constants k (Chemical bond force constant) : single bond 5 x 102 N/m Force Constants k (Chemical bond force constant) : single bond 5 x 102 N/m](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-51.jpg)
![Force Constants C=C bond: � = 4. 12√k / m K = 106 dynes/cm Force Constants C=C bond: � = 4. 12√k / m K = 106 dynes/cm](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-52.jpg)
![Force Constants C-H Bond: �= 4. 12√k / m K = 5 x 105 Force Constants C-H Bond: �= 4. 12√k / m K = 5 x 105](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-53.jpg)
![Frequencies of vibration C C 2150 cm-1 C=C 1650 cm-1 C-C 1200 cm-1 increasing Frequencies of vibration C C 2150 cm-1 C=C 1650 cm-1 C-C 1200 cm-1 increasing](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-54.jpg)
![Frequencies of vibration As the atom bonded to carbon increases in mass, the Quantity Frequencies of vibration As the atom bonded to carbon increases in mass, the Quantity](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-55.jpg)
![Frequencies of vibration Bending motion easier than stretching motions (The force constant K is Frequencies of vibration Bending motion easier than stretching motions (The force constant K is](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-56.jpg)
![Frequencies of vibration Hybridization affects the K values sp C-H 3300 2020/11/22 sp 2 Frequencies of vibration Hybridization affects the K values sp C-H 3300 2020/11/22 sp 2](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-57.jpg)
![Example 2020/11/22 58 Example 2020/11/22 58](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-58.jpg)
![Frequencies of Vibration C C C = C 2150 cm-1 1650 cm-1 C C Frequencies of Vibration C C C = C 2150 cm-1 1650 cm-1 C C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-59.jpg)
![Frequencies of Vibration Resonance: C=O 1715 cm-1 2020/11/22 1675 ~ 1680 cm-1 60 Frequencies of Vibration Resonance: C=O 1715 cm-1 2020/11/22 1675 ~ 1680 cm-1 60](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-60.jpg)
![Substituent Effects Hyperchromic e Bathochromic (red shift) Hypsochromic (blue shift) Hypochromic UV Profiles 2020/11/22 Substituent Effects Hyperchromic e Bathochromic (red shift) Hypsochromic (blue shift) Hypochromic UV Profiles 2020/11/22](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-61.jpg)
![Substitution Effects on IR Peaks n Electronic effects n Intramolecular factors n Inductive effects Substitution Effects on IR Peaks n Electronic effects n Intramolecular factors n Inductive effects](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-62.jpg)
![n Conjugated Effects cm -1 2020/11/22 cm -1 63 n Conjugated Effects cm -1 2020/11/22 cm -1 63](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-63.jpg)
![n Space Effects n Steric Hindrance n Ring Strain 1576 cm 3060 -3030 cm-1 n Space Effects n Steric Hindrance n Ring Strain 1576 cm 3060 -3030 cm-1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-64.jpg)
![2.Intermolecular Factors 2020/11/22 65 2.Intermolecular Factors 2020/11/22 65](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-65.jpg)
![Example 2020/11/22 66 Example 2020/11/22 66](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-66.jpg)
![Symbols of Vibrations s = symmetric as = asymmetirc ν = stretching vibrations (bonding Symbols of Vibrations s = symmetric as = asymmetirc ν = stretching vibrations (bonding](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-67.jpg)
![Characterization of IR Spectra Fingerprint Region: 1450 to 600 cm-1 region Group Frequency Region: Characterization of IR Spectra Fingerprint Region: 1450 to 600 cm-1 region Group Frequency Region:](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-68.jpg)
![Degree of Freedom (DF) According to Cartesian to describe positions: Each atom has 3 Degree of Freedom (DF) According to Cartesian to describe positions: Each atom has 3](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-69.jpg)
![Degree of Freedom (DF) DF of Linear CO 2: 2020/11/22 70 Degree of Freedom (DF) DF of Linear CO 2: 2020/11/22 70](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-70.jpg)
![Degree of Freedom (DF) Three fundamental vibrations of nonlinear triatomic water molecule: 2020/11/22 71 Degree of Freedom (DF) Three fundamental vibrations of nonlinear triatomic water molecule: 2020/11/22 71](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-71.jpg)
![Vibration Modes CH 2 group A. Stretching vibrations Change of bond length B. Deformation Vibration Modes CH 2 group A. Stretching vibrations Change of bond length B. Deformation](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-72.jpg)
![Fingerprint Regions Localized vibrations: spectra below 1500 cm-1 are difficult to interpretation, which, we Fingerprint Regions Localized vibrations: spectra below 1500 cm-1 are difficult to interpretation, which, we](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-73.jpg)
![Group Frequency Regions Absorption bands in the 4000 to 1450 cm-1 region are usually Group Frequency Regions Absorption bands in the 4000 to 1450 cm-1 region are usually](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-74.jpg)
![Some General Trends i) Stretching frequencies are higher than corresponding bending frequencies. (It is Some General Trends i) Stretching frequencies are higher than corresponding bending frequencies. (It is](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-75.jpg)
![Characterization of IR Spectra Carbonyl/ethylene groups C=O 1850 ~1630 cm-1, sharp & intensity C=C Characterization of IR Spectra Carbonyl/ethylene groups C=O 1850 ~1630 cm-1, sharp & intensity C=C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-76.jpg)
![Characterization of IR Spectra Important infrared frequencies: The IR spectra of complicated molecules have Characterization of IR Spectra Important infrared frequencies: The IR spectra of complicated molecules have](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-77.jpg)
![Characterization of IR Spectra N-H & O-H regions usually overlap O-H 3650 ~ 3200 Characterization of IR Spectra N-H & O-H regions usually overlap O-H 3650 ~ 3200](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-78.jpg)
![Characterization of IR Spectra Hydrogen Bonding X— H --- Y : s-orbital of proton Characterization of IR Spectra Hydrogen Bonding X— H --- Y : s-orbital of proton](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-79.jpg)
![Characterization of IR Spectra Intra- H-bond is stronger when a six-membered ring is formed. Characterization of IR Spectra Intra- H-bond is stronger when a six-membered ring is formed.](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-80.jpg)
![Characterization of IR Spectra Stretching frequencies in hydrogen bonding X— H --- Y Weak Characterization of IR Spectra Stretching frequencies in hydrogen bonding X— H --- Y Weak](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-81.jpg)
![Analysis of Spectra 1. If C=O 1820 ~ 1660 cm-1 : the strongest peak Analysis of Spectra 1. If C=O 1820 ~ 1660 cm-1 : the strongest peak](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-82.jpg)
![Analysis of Spectra 2. If C=O absent Alcohol/phenol: check for OH - broad near Analysis of Spectra 2. If C=O absent Alcohol/phenol: check for OH - broad near](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-83.jpg)
![Analysis of Spectra 3. Double bonds/or Aromatic rings Alkene: -C=C is weak near 1650 Analysis of Spectra 3. Double bonds/or Aromatic rings Alkene: -C=C is weak near 1650](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-84.jpg)
![Analysis of Spectra 5. Nitro group - two strong peaks at 1600 -1500 & Analysis of Spectra 5. Nitro group - two strong peaks at 1600 -1500 &](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-85.jpg)
![Summary of IR Absorptions 2020/11/22 86 Summary of IR Absorptions 2020/11/22 86](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-86.jpg)
![Characterization of IR Spectra 2020/11/22 87 Characterization of IR Spectra 2020/11/22 87](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-87.jpg)
![Problem Set 1. Analysis of C 5 H 10 O IR Spectrum 2020/11/22 88 Problem Set 1. Analysis of C 5 H 10 O IR Spectrum 2020/11/22 88](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-88.jpg)
![Problem Set 2. Analysis of C 8 H 8 O IR Spectrum 2020/11/22 89 Problem Set 2. Analysis of C 8 H 8 O IR Spectrum 2020/11/22 89](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-89.jpg)
![Problem Set 3. Analysis of C 7 H 8 O IR Spectrum 2020/11/22 90 Problem Set 3. Analysis of C 7 H 8 O IR Spectrum 2020/11/22 90](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-90.jpg)
![Problem Set 4. Analysis of C 8 H 7 N IR Spectrum 2020/11/22 91 Problem Set 4. Analysis of C 8 H 7 N IR Spectrum 2020/11/22 91](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-91.jpg)
![Problem Set 5. Analysis: C 7 H 6 O IR Spectrum 2020/11/22 92 Problem Set 5. Analysis: C 7 H 6 O IR Spectrum 2020/11/22 92](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-92.jpg)
![Problem Set 6. Analysis: C 3 H 7 NO IR Spectrum 2020/11/22 93 Problem Set 6. Analysis: C 3 H 7 NO IR Spectrum 2020/11/22 93](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-93.jpg)
![Problem Set 7. Analysis: C 4 H 8 O 2 IR Spectrum 2020/11/22 94 Problem Set 7. Analysis: C 4 H 8 O 2 IR Spectrum 2020/11/22 94](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-94.jpg)
![Problem Set 8. Analysis: C 7 H 5 OCl IR Spectrum 2020/11/22 95 Problem Set 8. Analysis: C 7 H 5 OCl IR Spectrum 2020/11/22 95](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-95.jpg)
![Problem Set 9. Analysis: C 6 H 6 S IR Spectrum 2020/11/22 96 Problem Set 9. Analysis: C 6 H 6 S IR Spectrum 2020/11/22 96](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-96.jpg)
![Problem Set 10. Analysis: C 4 H 6 IR Spectrum 2020/11/22 97 Problem Set 10. Analysis: C 4 H 6 IR Spectrum 2020/11/22 97](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-97.jpg)
![Solutions of Problem Set No. 1: 3 -pentanone No. 4: benzyl nitrile No. 7: Solutions of Problem Set No. 1: 3 -pentanone No. 4: benzyl nitrile No. 7:](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-98.jpg)
![A Survey of the Important Functional Groups With Examples 2020/11/22 99 A Survey of the Important Functional Groups With Examples 2020/11/22 99](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-99.jpg)
![Characterization of IR Spectra 9. Hydrocarbons: Alkanes, Alkenes, and Alkynes A. Alkanes C-H stretch Characterization of IR Spectra 9. Hydrocarbons: Alkanes, Alkenes, and Alkynes A. Alkanes C-H stretch](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-100.jpg)
![Characterization of IR Spectra B. Alkene =C-H stretch 3100 -3000 =C-H out-of-plane (oop) bending, Characterization of IR Spectra B. Alkene =C-H stretch 3100 -3000 =C-H out-of-plane (oop) bending,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-101.jpg)
![Characterization of IR Spectra Aromatic rings =C-H stretch, 3100 ~ 3000 =C-H out-of-plane (oop) Characterization of IR Spectra Aromatic rings =C-H stretch, 3100 ~ 3000 =C-H out-of-plane (oop)](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-102.jpg)
![Characterization of IR Spectra C. Alkynes C-H stretch ~ 3300 (3. 0 m) -C Characterization of IR Spectra C. Alkynes C-H stretch ~ 3300 (3. 0 m) -C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-103.jpg)
![An Alkyne IR Spectrum 2020/11/22 104 An Alkyne IR Spectrum 2020/11/22 104](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-104.jpg)
![Characterization of IR Spectra Table 2. Physical constants for sp, sp 2, sp 3 Characterization of IR Spectra Table 2. Physical constants for sp, sp 2, sp 3](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-105.jpg)
![Characterization of IR Spectra C-H Stretch Region 3300 3. 03 m 3100 3. 22 Characterization of IR Spectra C-H Stretch Region 3300 3. 03 m 3100 3. 22](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-106.jpg)
![Characterization of IR Spectra Table 3. The stretching vibrations for various sp 3 hybridized Characterization of IR Spectra Table 3. The stretching vibrations for various sp 3 hybridized](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-107.jpg)
![Characterization of IR Spectra C-H Bending Vibrations CH 2 CH 3 Scissoring 1465 Bending Characterization of IR Spectra C-H Bending Vibrations CH 2 CH 3 Scissoring 1465 Bending](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-108.jpg)
![Characterization of IR Spectra C=C Stretching Vibrations Conjugated effects. 1660 -1640 cm-1 Ring size Characterization of IR Spectra C=C Stretching Vibrations Conjugated effects. 1660 -1640 cm-1 Ring size](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-109.jpg)
![Characterization of IR Spectra 1650 1646 1611 1566 Angle > 90 1641 Angle < Characterization of IR Spectra 1650 1646 1611 1566 Angle > 90 1641 Angle <](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-110.jpg)
![Characterization of IR Spectra External (exo) double bonds 1950 1780 1678 1657 1655 1651 Characterization of IR Spectra External (exo) double bonds 1950 1780 1678 1657 1655 1651](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-111.jpg)
![Characterization of IR Spectra C-H Bending Vibrations for Alkenes In-plane scissoring: ~ 1415 Out-of-plane Characterization of IR Spectra C-H Bending Vibrations for Alkenes In-plane scissoring: ~ 1415 Out-of-plane](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-112.jpg)
![Characterization of IR Spectra 10 11 12 13 14 15 m Monosubst. s s Characterization of IR Spectra 10 11 12 13 14 15 m Monosubst. s s](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-113.jpg)
![11 12 13 14 15 m Monosubst. s Ortho s m Meta s s 11 12 13 14 15 m Monosubst. s Ortho s m Meta s s](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-114.jpg)
![Characterization of IR Spectra D. Alcohols and Phenols O-H “free” O-H C-O 2020/11/22 sharp, Characterization of IR Spectra D. Alcohols and Phenols O-H “free” O-H C-O 2020/11/22 sharp,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-115.jpg)
![An Alcohol IR Spectrum 2020/11/22 116 An Alcohol IR Spectrum 2020/11/22 116](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-116.jpg)
![Characterization of IR Spectra Table. The C-O and O-H stretching vibrations in Alcohols and Characterization of IR Spectra Table. The C-O and O-H stretching vibrations in Alcohols and](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-117.jpg)
![Characterization of IR Spectra E. Ethers C-O stretch, 1300 ~ 1000 phenyl & vinyl Characterization of IR Spectra E. Ethers C-O stretch, 1300 ~ 1000 phenyl & vinyl](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-118.jpg)
![Characterization of IR Spectra F. Carbonyl compounds 1810 1800 1760 acid chloride Anhydride anhydride Characterization of IR Spectra F. Carbonyl compounds 1810 1800 1760 acid chloride Anhydride anhydride](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-119.jpg)
![Characterization of IR Spectra F-1. Factors affect C=O vibration 1. Conjugated effects. a, b-unsaturated, Characterization of IR Spectra F-1. Factors affect C=O vibration 1. Conjugated effects. a, b-unsaturated,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-120.jpg)
![Characterization of IR Spectra 2. Ring size effects 1715 1745 2020/11/22 1715 1780 1735 Characterization of IR Spectra 2. Ring size effects 1715 1745 2020/11/22 1715 1780 1735](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-121.jpg)
![Characterization of IR Spectra 3. Alpha-substitution effects Axial Cl ~ 1725 2020/11/22 Equatorial Cl Characterization of IR Spectra 3. Alpha-substitution effects Axial Cl ~ 1725 2020/11/22 Equatorial Cl](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-122.jpg)
![Characterization of IR Spectra 4. Hydrogen Bonding Effects 1680 2020/11/22 123 Characterization of IR Spectra 4. Hydrogen Bonding Effects 1680 2020/11/22 123](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-123.jpg)
![Characterization of IR Spectra 5. Cyclic ketones 1815 1780 1745 1715 1705 Ring strain Characterization of IR Spectra 5. Cyclic ketones 1815 1780 1745 1715 1705 Ring strain](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-124.jpg)
![Characterization of IR Spectra 6. Carboxylic Acids O-H stretch, very broad (strongly H-bond) 3400 Characterization of IR Spectra 6. Carboxylic Acids O-H stretch, very broad (strongly H-bond) 3400](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-125.jpg)
![Characterization of IR Spectra 7. Esters (R-C(=O)-O-R’) C=O stretch, 1735 a. conjugation at the Characterization of IR Spectra 7. Esters (R-C(=O)-O-R’) C=O stretch, 1735 a. conjugation at the](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-126.jpg)
![Characterization of IR Spectra Table. The general effects of a, b-unsaturation or aryl Substitution Characterization of IR Spectra Table. The general effects of a, b-unsaturation or aryl Substitution](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-127.jpg)
![Characterization of IR Spectra Table. The Effects of Ring Size, a, b-unsaturation, and Conjugation Characterization of IR Spectra Table. The Effects of Ring Size, a, b-unsaturation, and Conjugation](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-128.jpg)
![Characterization of IR Spectra 8. Amides C=O stretch, 1670 ~ 1640 N-H stretch (1 Characterization of IR Spectra 8. Amides C=O stretch, 1670 ~ 1640 N-H stretch (1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-129.jpg)
![Characterization of IR Spectra 9. Acid Chlorides C=O stretch at ~ 1800 conjugation moves Characterization of IR Spectra 9. Acid Chlorides C=O stretch at ~ 1800 conjugation moves](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-130.jpg)
![Characterization of IR Spectra G. Amines N-H stretch, 3500~3300 1 -, 2 bands; 2 Characterization of IR Spectra G. Amines N-H stretch, 3500~3300 1 -, 2 bands; 2](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-131.jpg)
![Characterization of IR Spectra H. Nitriles, Isocyanates and Imines -C N stretch, sharp ~ Characterization of IR Spectra H. Nitriles, Isocyanates and Imines -C N stretch, sharp ~](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-132.jpg)
![Characterization of IR Spectra J. Nitro Compounds N=O stretch, two strong bands, 1600 ~ Characterization of IR Spectra J. Nitro Compounds N=O stretch, two strong bands, 1600 ~](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-133.jpg)
![Characterization of IR Spectra J-1. Carboxylate Salts, RC(=O)-Oasym ~1600 (s) sym ~1400 (s) J-2. Characterization of IR Spectra J-1. Carboxylate Salts, RC(=O)-Oasym ~1600 (s) sym ~1400 (s) J-2.](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-134.jpg)
![Characterization of IR Spectra K. Sulfur Compounds Mercaptans S-H stretch, ~ 2550 (w) Sulfides, Characterization of IR Spectra K. Sulfur Compounds Mercaptans S-H stretch, ~ 2550 (w) Sulfides,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-135.jpg)
![Characterization of IR Spectra L. Alkyl and Aryl Halides Fluorides C-F stretch, 1400~1000 (s) Characterization of IR Spectra L. Alkyl and Aryl Halides Fluorides C-F stretch, 1400~1000 (s)](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-136.jpg)
![Infrared Sources and Transducers Infrared sources: An inert solid with continuous radiation at heated Infrared Sources and Transducers Infrared sources: An inert solid with continuous radiation at heated](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-137.jpg)
![1. The Nernst Glower temperature: 1200 ~ 2200 K 2. The Globar Source a 1. The Nernst Glower temperature: 1200 ~ 2200 K 2. The Globar Source a](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-138.jpg)
![Sample Handling Techniques n Neat liquids: 一滴樣品夾於二鹽片(rock-salt plate)間(厚 度約為 ≦ 0. 01 mm), a Sample Handling Techniques n Neat liquids: 一滴樣品夾於二鹽片(rock-salt plate)間(厚 度約為 ≦ 0. 01 mm), a](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-139.jpg)
![2020/11/22 140 2020/11/22 140](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-140.jpg)
![2020/11/22 141 2020/11/22 141](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-141.jpg)
- Slides: 141
![Spectroscopy Infrared Spectroscopy Spectroscopy Infrared Spectroscopy](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-1.jpg)
Spectroscopy Infrared Spectroscopy
![Introduction n Spectroscopy is an analytical technique which helps determine structure n It destroys Introduction n Spectroscopy is an analytical technique which helps determine structure n It destroys](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-2.jpg)
Introduction n Spectroscopy is an analytical technique which helps determine structure n It destroys little or no sample n The amount of light absorbed by the sample is measured as wavelength is varied 2020/11/22 2
![Electromagnetic Spectrum n Examples X rays microwaves radio waves visible light IR and UV Electromagnetic Spectrum n Examples: X rays, microwaves, radio waves, visible light, IR, and UV](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-3.jpg)
Electromagnetic Spectrum n Examples: X rays, microwaves, radio waves, visible light, IR, and UV n Frequency and wavelength are inversely proportional n c = ln, where c is the speed of light n Energy per photon = hn, where h is Planck’s constant 2020/11/22 3
![The Electromagnetic Spectrum High Xray Frequency Energy UV uv 200 nm 20201122 IR visible The Electromagnetic Spectrum High X-ray Frequency Energy UV uv 200 nm 2020/11/22 IR visible](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-4.jpg)
The Electromagnetic Spectrum High X-ray Frequency Energy UV uv 200 nm 2020/11/22 IR visible 400 nm Low Micro Radio wave NMR Vibrational IR 800 nm 2. 5 m 1 m 5 m 4
![Energy Transitions Table 1 Types of energy transitions of the electromagnetic spectrum Region of Energy Transitions Table 1. Types of energy transitions of the electromagnetic spectrum Region of](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-5.jpg)
Energy Transitions Table 1. Types of energy transitions of the electromagnetic spectrum Region of spectrum Energy transition X-rays UV/Visible IR Microwave Radiofrequencies 2020/11/22 Bond breaking Electronic Vibrational Rotational Nuclear spin (NMR) Electron spin (ESR) 5
![The Spectrum and Molecular Effects 20201122 6 The Spectrum and Molecular Effects => 2020/11/22 6](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-6.jpg)
The Spectrum and Molecular Effects => 2020/11/22 6
![The IR Region n Just below red in the visible region n Wavelengths usually The IR Region n Just below red in the visible region n Wavelengths usually](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-7.jpg)
The IR Region n Just below red in the visible region n Wavelengths usually 2. 5 -25 mm n More common units are wavenumbers, or cm-1, the reciprocal of the wavelength in centimeters (4000 - 400 cm-1) n Wavenumbers are proportional to frequency and energy 2020/11/22 7
![Molecular Vibrations n Light is absorbed when radiation frequency frequency of vibration in Molecular Vibrations n Light is absorbed when radiation frequency = frequency of vibration in](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-8.jpg)
Molecular Vibrations n Light is absorbed when radiation frequency = frequency of vibration in molecule n Covalent bonds vibrate at only certain allowable frequencies n Associated with types of bonds and movement of atoms n Vibrations include stretching and bending 2020/11/22 8
![IR Spectrum Baseline Absorbance Peak n No two molecules will give exactly the same IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-9.jpg)
IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same IR spectrum (except enantiomers) n Simple stretching: 1600 -3500 cm-1 n Complex vibrations: 400 -1400 cm-1, called the “fingerprint region” 2020/11/22 9
![Interpretation n Looking for presenceabsence of functional groups n Correlation tables n A polar Interpretation n Looking for presence/absence of functional groups n Correlation tables n A polar](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-10.jpg)
Interpretation n Looking for presence/absence of functional groups n Correlation tables n A polar bond is usually IR-active n A nonpolar bond in a symmetrical molecule will absorb weakly or not at all 2020/11/22 10
![CarbonCarbon Bond Stretching n Stronger bonds absorb at higher frequencies n CC 1200 cm1 Carbon-Carbon Bond Stretching n Stronger bonds absorb at higher frequencies: n C-C 1200 cm-1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-11.jpg)
Carbon-Carbon Bond Stretching n Stronger bonds absorb at higher frequencies: n C-C 1200 cm-1 n C=C 1660 cm-1 n C C 2200 cm-1 (weak or absent if internal) n Conjugation lowers the frequency: n isolated C=C 1640 -1680 cm-1 n conjugated C=C 1620 -1640 cm-1 n aromatic C=C approx. 1600 cm-1 2020/11/22 11
![CarbonHydrogen Stretching n Bonds with more s character absorb at a higher frequency sp Carbon-Hydrogen Stretching n Bonds with more s character absorb at a higher frequency sp](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-12.jpg)
Carbon-Hydrogen Stretching n Bonds with more s character absorb at a higher frequency sp 3 C-H, just below 3000 cm-1 (to the right) n sp 2 C-H, just above 3000 cm-1 (to the left) n sp C-H, at 3300 cm-1 n 2020/11/22 12
![An Alkane IR Spectrum 20201122 13 An Alkane IR Spectrum 2020/11/22 13](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-13.jpg)
An Alkane IR Spectrum 2020/11/22 13
![An Alkene IR Spectrum 20201122 14 An Alkene IR Spectrum 2020/11/22 14](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-14.jpg)
An Alkene IR Spectrum 2020/11/22 14
![An Alkyne IR Spectrum 20201122 15 An Alkyne IR Spectrum 2020/11/22 15](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-15.jpg)
An Alkyne IR Spectrum 2020/11/22 15
![OH and NH Stretching n Both of these occur around 3300 cm1 but they O-H and N-H Stretching n Both of these occur around 3300 cm-1, but they](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-16.jpg)
O-H and N-H Stretching n Both of these occur around 3300 cm-1, but they look different Alcohol O-H, broad with rounded tip n Secondary amine (R 2 NH), broad with one sharp spike n Primary amine (RNH 2), broad with two sharp spikes n No signal for a tertiary amine (R 3 N) n 2020/11/22 16
![An Alcohol IR Spectrum 20201122 17 An Alcohol IR Spectrum 2020/11/22 17](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-17.jpg)
An Alcohol IR Spectrum 2020/11/22 17
![An Amine IR Spectrum 20201122 18 An Amine IR Spectrum 2020/11/22 18](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-18.jpg)
An Amine IR Spectrum 2020/11/22 18
![Carbonyl Stretching n The CO bond of simple ketones aldehydes and carboxylic acids absorb Carbonyl Stretching n The C=O bond of simple ketones, aldehydes, and carboxylic acids absorb](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-19.jpg)
Carbonyl Stretching n The C=O bond of simple ketones, aldehydes, and carboxylic acids absorb around 1710 cm-1 n Usually, it’s the strongest IR signal n Carboxylic acids will have O-H also n Aldehydes have two C-H signals around 2700 and 2800 cm-1 2020/11/22 19
![A Ketone IR Spectrum 20201122 20 A Ketone IR Spectrum 2020/11/22 20](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-20.jpg)
A Ketone IR Spectrum 2020/11/22 20
![An Aldehyde IR Spectrum 20201122 21 An Aldehyde IR Spectrum 2020/11/22 21](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-21.jpg)
An Aldehyde IR Spectrum 2020/11/22 21
![OH Stretch of a Carboxylic Acid This OH absorbs broadly 2500 3500 cm1 due O-H Stretch of a Carboxylic Acid This O-H absorbs broadly, 2500 -3500 cm-1, due](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-22.jpg)
O-H Stretch of a Carboxylic Acid This O-H absorbs broadly, 2500 -3500 cm-1, due to strong hydrogen bonding 2020/11/22 22
![Variations in CO Absorption n Conjugation of CO with CC lowers the stretching frequency Variations in C=O Absorption n Conjugation of C=O with C=C lowers the stretching frequency](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-23.jpg)
Variations in C=O Absorption n Conjugation of C=O with C=C lowers the stretching frequency to ~1680 cm-1 n The C=O group of an amide absorbs at an even lower frequency, 1640 -1680 cm-1 n The C=O of an ester absorbs at a higher frequency, ~1730 -1740 cm-1 n Carbonyl groups in small rings (5 C’s or less) absorb at an even higher frequency 2020/11/22 23
![An Amide IR Spectrum 20201122 24 An Amide IR Spectrum 2020/11/22 24](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-24.jpg)
An Amide IR Spectrum 2020/11/22 24
![Carbon Nitrogen Stretching n C N absorbs around 1200 cm1 n C Carbon - Nitrogen Stretching n C - N absorbs around 1200 cm-1 n C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-25.jpg)
Carbon - Nitrogen Stretching n C - N absorbs around 1200 cm-1 n C = N absorbs around 1660 cm-1 and is much stronger than the C = C absorption in the same region n C N absorbs strongly just above 2200 cm-1. The alkyne C C signal is much weaker and is just below 2200 cm-1 2020/11/22 25
![A Nitrile IR Spectrum 20201122 26 A Nitrile IR Spectrum 2020/11/22 26](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-26.jpg)
A Nitrile IR Spectrum 2020/11/22 26
![Summary of IR Absorptions 20201122 27 Summary of IR Absorptions 2020/11/22 27](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-27.jpg)
Summary of IR Absorptions 2020/11/22 27
![Strengths and Limitations n IR alone cannot determine a structure n Some signals may Strengths and Limitations n IR alone cannot determine a structure n Some signals may](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-28.jpg)
Strengths and Limitations n IR alone cannot determine a structure n Some signals may be ambiguous n The functional group is usually indicated n The absence of a signal is definite proof that the functional group is absent n Correspondence with a known sample’s IR spectrum confirms the identity of the compound 2020/11/22 28
![Infrared Regions Region wavelength wavenumber frequency mm cm1 Hz Near Middle Far Most used Infrared Regions Region wavelength wavenumber frequency (mm) (cm-1) (Hz) Near Middle Far Most used](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-29.jpg)
Infrared Regions Region wavelength wavenumber frequency (mm) (cm-1) (Hz) Near Middle Far Most used 0. 78 ~ 2. 5 12800 ~ 4000 2. 5 ~ 50 4000 ~ 200 50 ~ 1000 200 ~ 10 2. 5 ~ 15 4000 ~ 670 2020/11/22 3. 8 x 1014~ 1. 2 x 1014~ 6. 0 x 1012~ 3. 0 x 1011 1. 2 x 1014~ 2. 0 x 1013 29
![IR Application Near IR 770 2500 nm 1 Using photometers or spectrophotometer similar IR Application Near IR: 770 ~ 2500 nm 1. Using photometers or spectrophotometer similar](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-30.jpg)
IR Application Near IR: 770 ~ 2500 nm 1. Using photometers or spectrophotometer similar to UV spectrometry 2. Application: routine quantitative determination of species, e. g. moisture, proteins, CHs, fats in agricultural, food, and chemical industries. 2020/11/22 30
![IR Application MidIR 1 Used largely for qualitative organic analysis and structural determination based IR Application Mid-IR: 1. Used largely for qualitative organic analysis and structural determination based](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-31.jpg)
IR Application Mid-IR: 1. Used largely for qualitative organic analysis and structural determination based on absorption spectra. 2. FT-IR has been used for quantitative analysis of complex gaseous, liquid, or solid mixtures. Far-IR: Used for qualitative analysis of pure inorganic or metal organic species. 2020/11/22 31
![IR Sources n An inert solid heated btw 1500 2000 k The max IR Sources n An inert solid heated btw 1500 ~ 2000 k, The max](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-32.jpg)
IR Sources n An inert solid heated btw 1500 ~ 2000 k, The max radiation ~ 5900 cm-1 (1. 7 m. M); at long wavelength, 1% of max ~ 670 cm-1 (15 m. M). n Types of Sources ►The Nernst Glower: rare earth oxides, negative temp coeff of resistance, heated to red heat ► The Globar Source: a silicon carbide rod, positive temp coeff, greater output at > 5 mm. 2020/11/22 32
![Types of Instruments for IR n Dispersive grating photometers used for qualitative work n Types of Instruments for IR n Dispersive grating photometers: used for qualitative work n](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-33.jpg)
Types of Instruments for IR n Dispersive grating photometers: used for qualitative work n Fourier transform photometers: used for both qualitative and quantitative works; speedy, reliable, and convenient n Nondispersive photometers: for quantitative use 2020/11/22 33
![IR Absorption Region λ 2 5 15 mm 10 4 cm 1 IR Absorption Region λ= 2. 5 ~ 15 mm (10 -4 cm = 1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-34.jpg)
IR Absorption Region λ= 2. 5 ~ 15 mm (10 -4 cm = 1 mm = 104 Ao). (4000 cm-1 ~ 666 cm-1 ) wavenumber: � (cm-1, reciprocal centimeters) �(cm-1) = 1 / (cm) ν(Hz) = � c = c (cm/sec) / (cm) wavenumber �(cm-1) = 104 / wavelength (mm) = 104 /�(cm-1) 2020/11/22 34
![Theoretical Introduction ΔE h ν h c λ h c Theoretical Introduction ΔE = h. ν = h c /λ = h c �](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-35.jpg)
Theoretical Introduction ΔE = h. ν = h c /λ = h c � C : velocity of light, 3 x 1010 cm/sec h : Planck’s constant ν : frequency (1/sec) λ : wavelength (mm) � : wavenumber (cm-1) 2020/11/22 35
![IR Absorption Process n A Quantized Process n Only selected frequencies energies of infrared IR Absorption Process n A Quantized Process: n Only selected frequencies (energies) of infrared](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-36.jpg)
IR Absorption Process n A Quantized Process: n Only selected frequencies (energies) of infrared n radiation will be absorbed by a molecule n Bonds have dipole moment, Yes ! n Symmetric bonds, No ! (e. g. H 2, Cl 2) 2020/11/22 36
![IR Application n Infrared spectrum can be a fingerprint used for identification n Infrared IR Application n Infrared spectrum can be a fingerprint used for identification. n Infrared](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-37.jpg)
IR Application n Infrared spectrum can be a fingerprint used for identification. n Infrared spectrum gives the structural information about a molecule. 2020/11/22 37
![Absorption UV example Transmittance T IIo Absorbance A Log IoI if no Absorption UV example Transmittance: T = I/Io Absorbance: A = Log Io/I if no](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-38.jpg)
Absorption UV example Transmittance: T = I/Io Absorbance: A = Log Io/I if no absorption, T = 1; A = 0 Most spectrometers display absorbance on vertical axis, and the commonly observed range from 0 (100% T) to 2 (1% T) max: The wavelength of maximum absorbance 2020/11/22 38
![An Infrared Spectrum 20201122 39 An Infrared Spectrum 2020/11/22 39](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-39.jpg)
An Infrared Spectrum 2020/11/22 39
![IR Spectrum Baseline Absorbance Peak n No two molecules will give exactly the same IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-40.jpg)
IR Spectrum Baseline Absorbance/ Peak n No two molecules will give exactly the same IR spectrum (except enantiomers) n Simple stretching: 1600 -3500 cm-1 n Complex vibrations: 400 -1400 cm-1, called the “fingerprint region” 2020/11/22 40
![Vibration Modes Symmetric Stretch Asymmetric Stretch Symmetric Bend 20201122 41 Vibration Modes Symmetric Stretch Asymmetric Stretch Symmetric Bend 2020/11/22 41](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-41.jpg)
Vibration Modes Symmetric Stretch Asymmetric Stretch Symmetric Bend 2020/11/22 41
![Vibration Modes of CH 2 Group n Gas Phase IR Spectrum of Formaldehyde H Vibration Modes of CH 2 Group n Gas Phase IR Spectrum of Formaldehyde, H](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-42.jpg)
Vibration Modes of CH 2 Group n Gas Phase IR Spectrum of Formaldehyde, H 2 C=O 2020/11/22 42
![Vibration Modes Sym Stretching 2853 Asym Stretching 2926 Scissoring 1450 Rocking Vibration Modes Sym. Stretching (~ 2853) Asym. Stretching (~ 2926) Scissoring (~ 1450) Rocking](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-43.jpg)
Vibration Modes Sym. Stretching (~ 2853) Asym. Stretching (~ 2926) Scissoring (~ 1450) Rocking (~ 720) in plane Stretching vibrations 2020/11/22 wagging (~ 1250) Twisting (~ 1250) Out of plane Bending Vibrations 43
![Basic Principle As for any harmonic oscillator the energy of bond vibration Eosc h Basic Principle As for any harmonic oscillator, the energy of bond vibration: Eosc h](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-44.jpg)
Basic Principle As for any harmonic oscillator, the energy of bond vibration: Eosc h νosc Applying Hooke’s Law K = - k. Δr K Restoring force - Arising force opposed to extension k Elasticity constant (unit: N / m = kg. m / sec 2 / m) ( ~ bond strength between two atoms) Δr extension 2020/11/22 44
![Basic Principle The natural frequency of the oscillation νosc ½ k Basic Principle The natural frequency of the oscillation νosc = ½ . √k /](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-45.jpg)
Basic Principle The natural frequency of the oscillation νosc = ½ . √k / m (1) Wave equation of quantum mechanics E = (n + ½) ½ h. √k / m (2) h : Planck’s const. n : vibration quantum number Take (1) into (2): Evib = h νosc (n + ½ ) 2020/11/22 45
![Basic Principle From SchrÖdiger Equation Evib h νosc n 12 vibration quantum Basic Principle From SchrÖdiger Equation: Evib = h νosc (n + 1/2) vibration quantum](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-46.jpg)
Basic Principle From SchrÖdiger Equation: Evib = h νosc (n + 1/2) vibration quantum number, n = 0, 1, 2, 3 ---- Ground state (n = 0): E 0 = ½ hνosc First excited state (n = 1): E 1 = 3/2 hνosc ΔEvib = E 1 – E 0 = 3/2 hνosc - ½ hνosc = hνosc 2020/11/22 46
![Basic Principle The frequency of radiation ν vibrational frequency νosc E radiation h Basic Principle The frequency of radiation, ν vibrational frequency, νosc E radiation = h](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-47.jpg)
Basic Principle The frequency of radiation, ν vibrational frequency, νosc E radiation = h ν = ΔEvib = hνosc = ½ h. √k / m or ν = νosc = ½ . √k / m 2020/11/22 47
![Basic Principle νosc 12 k m m m 1 m Basic Principle νosc = 1/2 . √k / m m = m 1. m](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-48.jpg)
Basic Principle νosc = 1/2 . √k / m m = m 1. m 2 / (m 1 + m 2) = reduced mass of atoms in AMU (unit: kg) ΔE vib = h. νosc = h / 2 . √k / m ν(cm-1) = E vib / h c = 1 / 2 c. √k / m = 5. 3 x 10 – 12 sec/cm. √k / m [ unit of √k / m : sec -1 ] 2020/11/22 48
![Example Calculate the wavenumber and wavelength of the fundamental frequency peak due to the Example Calculate the wavenumber and wavelength of the fundamental frequency peak due to the](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-49.jpg)
Example Calculate the wavenumber and wavelength of the fundamental frequency peak due to the stretching vibration of C=O group. Solution: m 1 = 12 x 10 -3 kg / mol / 6. 0 x 10 23 atoms / mol = 2. 0 x 10 – 26 kg m 2 = 16 x 10 -3 kg / mol / 6. 0 x 10 23 atoms / mol = 2. 7 x 10 – 26 kg m = m 1. m 2 / (m 1 + m 2) = 1. 1 x 10 – 26 kg �(cm-1) = 5. 3 x 10 – 12 s/cm. √ 1 x 10 3 N /m /2. 7 x 10 – 26 kg = 1. 6 x 103 cm-1 2020/11/22 49
![Example cm1 E vib h c 1 2 c k Example �(cm-1) = E vib / h c = 1 / 2 c. √k](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-50.jpg)
Example �(cm-1) = E vib / h c = 1 / 2 c. √k / m = 7. 76 x 1011/2 c √k / m’ (taking 6. 02 x 1023 out of root square) = 4. 12√k / m’ m‘ = M 1 M 2/(M 1+M 2); both are atomic weights. K : force constant in dynes/cm. 1 N = 1 kg m/sec 2 1 Dyne = 1 g cm/sec 2 2020/11/22 50
![Force Constants k Chemical bond force constant single bond 5 x 102 Nm Force Constants k (Chemical bond force constant) : single bond 5 x 102 N/m](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-51.jpg)
Force Constants k (Chemical bond force constant) : single bond 5 x 102 N/m = 5 x 105 dynes/cm double bond 1. 0 x 103 N/m = 106 dynes/cm triple bond 1. 5 x 103 N/m = 1. 5 x 106 dynes/cm 2020/11/22 51
![Force Constants CC bond 4 12k m K 106 dynescm Force Constants C=C bond: � = 4. 12√k / m K = 106 dynes/cm](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-52.jpg)
Force Constants C=C bond: � = 4. 12√k / m K = 106 dynes/cm m = 12 x 12/(12+12) = 6 �= 4. 12√ 106/6 = 1682 cm-1 (calculated) �= 1650 cm-1 (experimental) 2020/11/22 52
![Force Constants CH Bond 4 12k m K 5 x 105 Force Constants C-H Bond: �= 4. 12√k / m K = 5 x 105](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-53.jpg)
Force Constants C-H Bond: �= 4. 12√k / m K = 5 x 105 dynes/cm m = 12 x(1)/(12+1) = 0. 923 �= 4. 12√ 5 x 105/0. 923 = 3032 cm-1 (calculated) �= 3000 cm-1 (experimental) C-D Bond: � = 2206 cm-1 (experimental) 2020/11/22 53
![Frequencies of vibration C C 2150 cm1 CC 1650 cm1 CC 1200 cm1 increasing Frequencies of vibration C C 2150 cm-1 C=C 1650 cm-1 C-C 1200 cm-1 increasing](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-54.jpg)
Frequencies of vibration C C 2150 cm-1 C=C 1650 cm-1 C-C 1200 cm-1 increasing K 2020/11/22 54
![Frequencies of vibration As the atom bonded to carbon increases in mass the Quantity Frequencies of vibration As the atom bonded to carbon increases in mass, the Quantity](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-55.jpg)
Frequencies of vibration As the atom bonded to carbon increases in mass, the Quantity m increases, the frequency of vibration goes down. C-H 3000 cm-1 C-C 1200 cm-1 C-O 1100 cm-1 C-Cl 800 cm-1 C-Br 550 cm-1 C-I ~ 500 cm-1 Increasing m 2020/11/22 55
![Frequencies of vibration Bending motion easier than stretching motions The force constant K is Frequencies of vibration Bending motion easier than stretching motions (The force constant K is](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-56.jpg)
Frequencies of vibration Bending motion easier than stretching motions (The force constant K is smaller) C-H stretching ~ 3000 cm-1 2020/11/22 C-H bending ~ 1340 cm-1 56
![Frequencies of vibration Hybridization affects the K values sp CH 3300 20201122 sp 2 Frequencies of vibration Hybridization affects the K values sp C-H 3300 2020/11/22 sp 2](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-57.jpg)
Frequencies of vibration Hybridization affects the K values sp C-H 3300 2020/11/22 sp 2 =C-H 3100 sp 3 -C-H 2900 cm-1 57
![Example 20201122 58 Example 2020/11/22 58](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-58.jpg)
Example 2020/11/22 58
![Frequencies of Vibration C C C C 2150 cm1 1650 cm1 C C Frequencies of Vibration C C C = C 2150 cm-1 1650 cm-1 C C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-59.jpg)
Frequencies of Vibration C C C = C 2150 cm-1 1650 cm-1 C C 1200 cm-1 Increasing K C X stretching C H C C C O C Cl C Br C I 3000 1200 1100 800 550 ~500 cm-1 2020/11/22 59
![Frequencies of Vibration Resonance CO 1715 cm1 20201122 1675 1680 cm1 60 Frequencies of Vibration Resonance: C=O 1715 cm-1 2020/11/22 1675 ~ 1680 cm-1 60](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-60.jpg)
Frequencies of Vibration Resonance: C=O 1715 cm-1 2020/11/22 1675 ~ 1680 cm-1 60
![Substituent Effects Hyperchromic e Bathochromic red shift Hypsochromic blue shift Hypochromic UV Profiles 20201122 Substituent Effects Hyperchromic e Bathochromic (red shift) Hypsochromic (blue shift) Hypochromic UV Profiles 2020/11/22](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-61.jpg)
Substituent Effects Hyperchromic e Bathochromic (red shift) Hypsochromic (blue shift) Hypochromic UV Profiles 2020/11/22 400 blue 800 red nm 61
![Substitution Effects on IR Peaks n Electronic effects n Intramolecular factors n Inductive effects Substitution Effects on IR Peaks n Electronic effects n Intramolecular factors n Inductive effects](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-62.jpg)
Substitution Effects on IR Peaks n Electronic effects n Intramolecular factors n Inductive effects R-COR C=0 1715 cm-1 ; R-COH C=0 1730 cm -1 ; R-COCl C=0 1800 cm-1 ; R-COF C=0 1920 cm-1 ; F-COF C=0 1920 cm-1 ; R-CONH 2 C=0 1928 cm-1 ; 2020/11/22 62
![n Conjugated Effects cm 1 20201122 cm 1 63 n Conjugated Effects cm -1 2020/11/22 cm -1 63](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-63.jpg)
n Conjugated Effects cm -1 2020/11/22 cm -1 63
![n Space Effects n Steric Hindrance n Ring Strain 1576 cm 3060 3030 cm1 n Space Effects n Steric Hindrance n Ring Strain 1576 cm 3060 -3030 cm-1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-64.jpg)
n Space Effects n Steric Hindrance n Ring Strain 1576 cm 3060 -3030 cm-1 -1 1611 cm -1 1644 cm-1 2020/11/22 C H 2 2900 -2800 cm-1 1781 cm -1 1678 cm -1 1657 cm -1 1651 cm -1 64
![2Intermolecular Factors 20201122 65 2.Intermolecular Factors 2020/11/22 65](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-65.jpg)
2.Intermolecular Factors 2020/11/22 65
![Example 20201122 66 Example 2020/11/22 66](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-66.jpg)
Example 2020/11/22 66
![Symbols of Vibrations s symmetric as asymmetirc ν stretching vibrations bonding Symbols of Vibrations s = symmetric as = asymmetirc ν = stretching vibrations (bonding](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-67.jpg)
Symbols of Vibrations s = symmetric as = asymmetirc ν = stretching vibrations (bonding vibrations) δ = deformation vibrations (bending vibrations) γ = out-of-plane deformation vibrations τ = torsional vibrations 2020/11/22 67
![Characterization of IR Spectra Fingerprint Region 1450 to 600 cm1 region Group Frequency Region Characterization of IR Spectra Fingerprint Region: 1450 to 600 cm-1 region Group Frequency Region:](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-68.jpg)
Characterization of IR Spectra Fingerprint Region: 1450 to 600 cm-1 region Group Frequency Region: 4000 to 1450 cm-1 region 2020/11/22 68
![Degree of Freedom DF According to Cartesian to describe positions Each atom has 3 Degree of Freedom (DF) According to Cartesian to describe positions: Each atom has 3](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-69.jpg)
Degree of Freedom (DF) According to Cartesian to describe positions: Each atom has 3 degrees of freedom, (x, y, z). A molecule of n atoms has 3 n DF. For nonlinear molecules: 3 n-6 are fundamental vibration of DF. For linear molecules: 3 n-5 fundamental vibration of DF. fundamental vibration involves no change in the center of gravity of molecules 2020/11/22 69
![Degree of Freedom DF DF of Linear CO 2 20201122 70 Degree of Freedom (DF) DF of Linear CO 2: 2020/11/22 70](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-70.jpg)
Degree of Freedom (DF) DF of Linear CO 2: 2020/11/22 70
![Degree of Freedom DF Three fundamental vibrations of nonlinear triatomic water molecule 20201122 71 Degree of Freedom (DF) Three fundamental vibrations of nonlinear triatomic water molecule: 2020/11/22 71](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-71.jpg)
Degree of Freedom (DF) Three fundamental vibrations of nonlinear triatomic water molecule: 2020/11/22 71
![Vibration Modes CH 2 group A Stretching vibrations Change of bond length B Deformation Vibration Modes CH 2 group A. Stretching vibrations Change of bond length B. Deformation](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-72.jpg)
Vibration Modes CH 2 group A. Stretching vibrations Change of bond length B. Deformation vibrations (two types: planar or non-planar) Change of bond angle 2020/11/22 72
![Fingerprint Regions Localized vibrations spectra below 1500 cm1 are difficult to interpretation which we Fingerprint Regions Localized vibrations: spectra below 1500 cm-1 are difficult to interpretation, which, we](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-73.jpg)
Fingerprint Regions Localized vibrations: spectra below 1500 cm-1 are difficult to interpretation, which, we call it “fingerprint region”, are characteristic for the molecule as a whole. Most of them are derived from overtone or combination vibrations. 2020/11/22 73
![Group Frequency Regions Absorption bands in the 4000 to 1450 cm1 region are usually Group Frequency Regions Absorption bands in the 4000 to 1450 cm-1 region are usually](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-74.jpg)
Group Frequency Regions Absorption bands in the 4000 to 1450 cm-1 region are usually due to stretching vibrations of diatomic units 2020/11/22 74
![Some General Trends i Stretching frequencies are higher than corresponding bending frequencies It is Some General Trends i) Stretching frequencies are higher than corresponding bending frequencies. (It is](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-75.jpg)
Some General Trends i) Stretching frequencies are higher than corresponding bending frequencies. (It is easier to bend a bond than to stretch or compress it. ) ii) Bonds to hydrogen have higher stretching frequencies than those to heavier atoms. iii) Triple bonds have higher stretching frequencies than corresponding double bonds, which in turn have higher frequencies than single bonds. (Except for bonds to hydrogen). 2020/11/22 75
![Characterization of IR Spectra Carbonylethylene groups CO 1850 1630 cm1 sharp intensity CC Characterization of IR Spectra Carbonyl/ethylene groups C=O 1850 ~1630 cm-1, sharp & intensity C=C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-76.jpg)
Characterization of IR Spectra Carbonyl/ethylene groups C=O 1850 ~1630 cm-1, sharp & intensity C=C 1680 ~ 1620 cm-1, generally weak 2020/11/22 76
![Characterization of IR Spectra Important infrared frequencies The IR spectra of complicated molecules have Characterization of IR Spectra Important infrared frequencies: The IR spectra of complicated molecules have](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-77.jpg)
Characterization of IR Spectra Important infrared frequencies: The IR spectra of complicated molecules have many peaks, only a few of which can be easily interpreted. Here are the places to look at: 1500 – 1800 cm-1 : A strong signal for (C=O) or an imine. 2000 – 2200 cm-1 : stretch vibrations of triple bonds and cumulenes (-C≡N, -C≡C , -N=C=O, -C=C=O). 2900 – 3000 cm-1 : stretch vibrations of aliphatic C – H bond. 3000 – 3100 cm-1 : vinyl C – H bond stretches. 3100 – 3600 cm-1 : O – H bond stretches (broad if inter-molecularly at H-bonded). Be careful, since water appears in this region. 2020/11/22 77
![Characterization of IR Spectra NH OH regions usually overlap OH 3650 3200 Characterization of IR Spectra N-H & O-H regions usually overlap O-H 3650 ~ 3200](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-78.jpg)
Characterization of IR Spectra N-H & O-H regions usually overlap O-H 3650 ~ 3200 cm-1, broad peak N-H 3500 ~ 3300 cm-1, 1 or 2 sharp absorption bands of low intensity, O-H in this region usually gives broad peak. 2020/11/22 78
![Characterization of IR Spectra Hydrogen Bonding X H Y sorbital of proton Characterization of IR Spectra Hydrogen Bonding X— H --- Y : s-orbital of proton](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-79.jpg)
Characterization of IR Spectra Hydrogen Bonding X— H --- Y : s-orbital of proton overlapping with p- or -orbital of the acceptors. Common proton donor groups: -COOH, -OH, Amines, or amides. Common proton acceptors: O, N, halogens X— H : move to lower frequency with increased intensity. The acceptors, Y ( e. g. C=O), also move to lower frequency but to a less degree. Intermolecular H-bonding: usually in dimers (e. g. RCOOH), or in neat or concentrated solutions of R-OH. Temperature, concentration affect the inter or intra- H-bonding. 2020/11/22 79
![Characterization of IR Spectra Intra Hbond is stronger when a sixmembered ring is formed Characterization of IR Spectra Intra- H-bond is stronger when a six-membered ring is formed.](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-80.jpg)
Characterization of IR Spectra Intra- H-bond is stronger when a six-membered ring is formed. H-bond is strongest when the bonded structures is stabilized by resonance. 2020/11/22 80
![Characterization of IR Spectra Stretching frequencies in hydrogen bonding X H Y Weak Characterization of IR Spectra Stretching frequencies in hydrogen bonding X— H --- Y Weak](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-81.jpg)
Characterization of IR Spectra Stretching frequencies in hydrogen bonding X— H --- Y Weak Intermolecular bonding intramolecular bonding Frequency reduction(cm-1) ν OH ν CO comp’ds 300 15 R-OH, Ph. OH intermol OH to CO Medium Strong 2020/11/22 < 100 10 1, 2 -diols most b-OH ketones 100 ~ 300 50 >500 50 RCOOH dimers > 300 100 81
![Analysis of Spectra 1 If CO 1820 1660 cm1 the strongest peak Analysis of Spectra 1. If C=O 1820 ~ 1660 cm-1 : the strongest peak](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-82.jpg)
Analysis of Spectra 1. If C=O 1820 ~ 1660 cm-1 : the strongest peak Acid: Amide: Ester: Anhydride: Aldehyde: Ketone: 2020/11/22 is OH present? Broad near 3400~2400 is NH present? Medium peak ~3500 is C-O present? Strong at 1300~1000 two C=O ~ at 1810 & 1760 is C-H present? Two peaks ~ 2850 & 2750 the above 5 choices were eliminated 82
![Analysis of Spectra 2 If CO absent Alcoholphenol check for OH broad near Analysis of Spectra 2. If C=O absent Alcohol/phenol: check for OH - broad near](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-83.jpg)
Analysis of Spectra 2. If C=O absent Alcohol/phenol: check for OH - broad near 3600~3300 - confirm by C-O near 1300~1000 Amine: check for NH -medium peak near 3500 Ether: check for C-O near 1300~1000 2020/11/22 83
![Analysis of Spectra 3 Double bondsor Aromatic rings Alkene CC is weak near 1650 Analysis of Spectra 3. Double bonds/or Aromatic rings Alkene: -C=C is weak near 1650](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-84.jpg)
Analysis of Spectra 3. Double bonds/or Aromatic rings Alkene: -C=C is weak near 1650 Aromatic: -medium to strong at 1650~1450 Aromatic & vinyl CH: weak peak at 3000 4. Triple bond -C N: medium, sharp near 2250 -C C: weak, sharp near 2150 check also for acetylenic CH near 3300 2020/11/22 84
![Analysis of Spectra 5 Nitro group two strong peaks at 1600 1500 Analysis of Spectra 5. Nitro group - two strong peaks at 1600 -1500 &](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-85.jpg)
Analysis of Spectra 5. Nitro group - two strong peaks at 1600 -1500 & 1390 -1300 6. Hydrocarbon -none of above found -major peaks of CH near 3000 -very simple spectrum, others at 1450 & 1375 2020/11/22 85
![Summary of IR Absorptions 20201122 86 Summary of IR Absorptions 2020/11/22 86](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-86.jpg)
Summary of IR Absorptions 2020/11/22 86
![Characterization of IR Spectra 20201122 87 Characterization of IR Spectra 2020/11/22 87](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-87.jpg)
Characterization of IR Spectra 2020/11/22 87
![Problem Set 1 Analysis of C 5 H 10 O IR Spectrum 20201122 88 Problem Set 1. Analysis of C 5 H 10 O IR Spectrum 2020/11/22 88](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-88.jpg)
Problem Set 1. Analysis of C 5 H 10 O IR Spectrum 2020/11/22 88
![Problem Set 2 Analysis of C 8 H 8 O IR Spectrum 20201122 89 Problem Set 2. Analysis of C 8 H 8 O IR Spectrum 2020/11/22 89](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-89.jpg)
Problem Set 2. Analysis of C 8 H 8 O IR Spectrum 2020/11/22 89
![Problem Set 3 Analysis of C 7 H 8 O IR Spectrum 20201122 90 Problem Set 3. Analysis of C 7 H 8 O IR Spectrum 2020/11/22 90](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-90.jpg)
Problem Set 3. Analysis of C 7 H 8 O IR Spectrum 2020/11/22 90
![Problem Set 4 Analysis of C 8 H 7 N IR Spectrum 20201122 91 Problem Set 4. Analysis of C 8 H 7 N IR Spectrum 2020/11/22 91](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-91.jpg)
Problem Set 4. Analysis of C 8 H 7 N IR Spectrum 2020/11/22 91
![Problem Set 5 Analysis C 7 H 6 O IR Spectrum 20201122 92 Problem Set 5. Analysis: C 7 H 6 O IR Spectrum 2020/11/22 92](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-92.jpg)
Problem Set 5. Analysis: C 7 H 6 O IR Spectrum 2020/11/22 92
![Problem Set 6 Analysis C 3 H 7 NO IR Spectrum 20201122 93 Problem Set 6. Analysis: C 3 H 7 NO IR Spectrum 2020/11/22 93](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-93.jpg)
Problem Set 6. Analysis: C 3 H 7 NO IR Spectrum 2020/11/22 93
![Problem Set 7 Analysis C 4 H 8 O 2 IR Spectrum 20201122 94 Problem Set 7. Analysis: C 4 H 8 O 2 IR Spectrum 2020/11/22 94](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-94.jpg)
Problem Set 7. Analysis: C 4 H 8 O 2 IR Spectrum 2020/11/22 94
![Problem Set 8 Analysis C 7 H 5 OCl IR Spectrum 20201122 95 Problem Set 8. Analysis: C 7 H 5 OCl IR Spectrum 2020/11/22 95](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-95.jpg)
Problem Set 8. Analysis: C 7 H 5 OCl IR Spectrum 2020/11/22 95
![Problem Set 9 Analysis C 6 H 6 S IR Spectrum 20201122 96 Problem Set 9. Analysis: C 6 H 6 S IR Spectrum 2020/11/22 96](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-96.jpg)
Problem Set 9. Analysis: C 6 H 6 S IR Spectrum 2020/11/22 96
![Problem Set 10 Analysis C 4 H 6 IR Spectrum 20201122 97 Problem Set 10. Analysis: C 4 H 6 IR Spectrum 2020/11/22 97](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-97.jpg)
Problem Set 10. Analysis: C 4 H 6 IR Spectrum 2020/11/22 97
![Solutions of Problem Set No 1 3 pentanone No 4 benzyl nitrile No 7 Solutions of Problem Set No. 1: 3 -pentanone No. 4: benzyl nitrile No. 7:](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-98.jpg)
Solutions of Problem Set No. 1: 3 -pentanone No. 4: benzyl nitrile No. 7: ethyl acetate 2020/11/22 No. 2: acetophenone No. 5: benzaldehyde No. 8: benzoyl chloride No. 10: 1, 3 -butadiene No. 3: benzyl alcohol No. 6: N-methylacetamide No. 9: thiophenol 98
![A Survey of the Important Functional Groups With Examples 20201122 99 A Survey of the Important Functional Groups With Examples 2020/11/22 99](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-99.jpg)
A Survey of the Important Functional Groups With Examples 2020/11/22 99
![Characterization of IR Spectra 9 Hydrocarbons Alkanes Alkenes and Alkynes A Alkanes CH stretch Characterization of IR Spectra 9. Hydrocarbons: Alkanes, Alkenes, and Alkynes A. Alkanes C-H stretch](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-100.jpg)
Characterization of IR Spectra 9. Hydrocarbons: Alkanes, Alkenes, and Alkynes A. Alkanes C-H stretch ~2980 - 2800 cm-1 CH 2 ~ 1450 CH 3 ~ 1375 C-C stretch : not useful for interpretation 2020/11/22 100
![Characterization of IR Spectra B Alkene CH stretch 3100 3000 CH outofplane oop bending Characterization of IR Spectra B. Alkene =C-H stretch 3100 -3000 =C-H out-of-plane (oop) bending,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-101.jpg)
Characterization of IR Spectra B. Alkene =C-H stretch 3100 -3000 =C-H out-of-plane (oop) bending, 1000 -650 C=C 1660 -1600 (w) symmetrical type, no absorb symmetrical (cis), stronger 2020/11/22 101
![Characterization of IR Spectra Aromatic rings CH stretch 3100 3000 CH outofplane oop Characterization of IR Spectra Aromatic rings =C-H stretch, 3100 ~ 3000 =C-H out-of-plane (oop)](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-102.jpg)
Characterization of IR Spectra Aromatic rings =C-H stretch, 3100 ~ 3000 =C-H out-of-plane (oop) bending, 900 ~ 690 great utility to assign the ring substituted pattern C=C ring stretch, occurs in pair at 1600 & 1475 overtone/combination bands, 2000 ~ 1667 used to assign the ring substituted patterns 2020/11/22 102
![Characterization of IR Spectra C Alkynes CH stretch 3300 3 0 m C Characterization of IR Spectra C. Alkynes C-H stretch ~ 3300 (3. 0 m) -C](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-103.jpg)
Characterization of IR Spectra C. Alkynes C-H stretch ~ 3300 (3. 0 m) -C C stretch ~ 2150 (4. 65 m) disubstituted or symmetrical: no or weak absorption 2020/11/22 103
![An Alkyne IR Spectrum 20201122 104 An Alkyne IR Spectrum 2020/11/22 104](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-104.jpg)
An Alkyne IR Spectrum 2020/11/22 104
![Characterization of IR Spectra Table 2 Physical constants for sp sp 2 sp 3 Characterization of IR Spectra Table 2. Physical constants for sp, sp 2, sp 3](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-105.jpg)
Characterization of IR Spectra Table 2. Physical constants for sp, sp 2, sp 3 Hybridized carbon and the resulting C-H values Bond Type Length Strength IR freq. 2020/11/22 C-H sp- 1 s 1. 08Å 121 Kcal 3300 =C-H sp 2 - 1 s 1. 10Å 106 Kcal ~3100 -C-H sp 2 -1 s 1. 12Å 101 Kcal ~2900 105
![Characterization of IR Spectra CH Stretch Region 3300 3 03 m 3100 3 22 Characterization of IR Spectra C-H Stretch Region 3300 3. 03 m 3100 3. 22](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-106.jpg)
Characterization of IR Spectra C-H Stretch Region 3300 3. 03 m 3100 3. 22 m 3000 3. 33 m acetylenic vinyl =C-H aliph. C-H arom. =C-H cyclopropyl -C-H sp sp 2 2850 3. 51 m 2750 3. 64 m aldehyde -CH=O sp 3 Strain moves absorption to left Increasing s character moves to left 2020/11/22 106
![Characterization of IR Spectra Table 3 The stretching vibrations for various sp 3 hybridized Characterization of IR Spectra Table 3. The stretching vibrations for various sp 3 hybridized](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-107.jpg)
Characterization of IR Spectra Table 3. The stretching vibrations for various sp 3 hybridized C-H bonds Stretching vibration group Methyl CH 3 Methylene –CH 2 Methine –C-H 2020/11/22 asym. 2962 2926 2872 2853 2890 very weak 107
![Characterization of IR Spectra CH Bending Vibrations CH 2 CH 3 Scissoring 1465 Bending Characterization of IR Spectra C-H Bending Vibrations CH 2 CH 3 Scissoring 1465 Bending](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-108.jpg)
Characterization of IR Spectra C-H Bending Vibrations CH 2 CH 3 Scissoring 1465 Bending (as. ) bending (sy. ) 1450 Sometimes overlap 1375 1380 1370 Lone Me g’p Gem-dimethyl CH 2, ~ 720 rocking band 2020/11/22 108
![Characterization of IR Spectra CC Stretching Vibrations Conjugated effects 1660 1640 cm1 Ring size Characterization of IR Spectra C=C Stretching Vibrations Conjugated effects. 1660 -1640 cm-1 Ring size](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-109.jpg)
Characterization of IR Spectra C=C Stretching Vibrations Conjugated effects. 1660 -1640 cm-1 Ring size effects. The frequency of (endo) double bonds in cyclic compounds is sensitive to ring size. 2020/11/22 Higher freq. 109
![Characterization of IR Spectra 1650 1646 1611 1566 Angle 90 1641 Angle Characterization of IR Spectra 1650 1646 1611 1566 Angle > 90 1641 Angle <](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-110.jpg)
Characterization of IR Spectra 1650 1646 1611 1566 Angle > 90 1641 Angle < 90 ~ 1611 Figure 3. C=C Stretching vibrations in endocyclic Systems 2020/11/22 110
![Characterization of IR Spectra External exo double bonds 1950 1780 1678 1657 1655 1651 Characterization of IR Spectra External (exo) double bonds 1950 1780 1678 1657 1655 1651](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-111.jpg)
Characterization of IR Spectra External (exo) double bonds 1950 1780 1678 1657 1655 1651 H 2 C=C=CH 2 Allene (a) Strain moves the peak to the left (b) Ring fusion moves the absorption to the left 2020/11/22 111
![Characterization of IR Spectra CH Bending Vibrations for Alkenes Inplane scissoring 1415 Outofplane Characterization of IR Spectra C-H Bending Vibrations for Alkenes In-plane scissoring: ~ 1415 Out-of-plane](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-112.jpg)
Characterization of IR Spectra C-H Bending Vibrations for Alkenes In-plane scissoring: ~ 1415 Out-of-plane region: 1000 ~ 650 Valuable to indicate the substitution patterns 2020/11/22 112
![Characterization of IR Spectra 10 11 12 13 14 15 m Monosubst s s Characterization of IR Spectra 10 11 12 13 14 15 m Monosubst. s s](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-113.jpg)
Characterization of IR Spectra 10 11 12 13 14 15 m Monosubst. s s s cis-1, 2 trans-1, 2 1, 1 -disubst. trisubst. s s m tetrasubst. 1000 900 800 700 cm-1 Figure. The C-H out-of-plane bending vibrations for 2020/11/22 substituted alkenes 113
![11 12 13 14 15 m Monosubst s Ortho s m Meta s s 11 12 13 14 15 m Monosubst. s Ortho s m Meta s s](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-114.jpg)
11 12 13 14 15 m Monosubst. s Ortho s m Meta s s Para m 1, 2, 4 - s s 1, 2, 3 - m s m 900 800 700 cm-1 1, 3, 5 - 2020/11/22 C-H oop C=C oop 114
![Characterization of IR Spectra D Alcohols and Phenols OH free OH CO 20201122 sharp Characterization of IR Spectra D. Alcohols and Phenols O-H “free” O-H C-O 2020/11/22 sharp,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-115.jpg)
Characterization of IR Spectra D. Alcohols and Phenols O-H “free” O-H C-O 2020/11/22 sharp, 3650~3600 if no H-bonding. H-bonded O-H, broad at 3500~3200 , usually in neat (pure) liquids. 1250~1000(s) 115
![An Alcohol IR Spectrum 20201122 116 An Alcohol IR Spectrum 2020/11/22 116](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-116.jpg)
An Alcohol IR Spectrum 2020/11/22 116
![Characterization of IR Spectra Table The CO and OH stretching vibrations in Alcohols and Characterization of IR Spectra Table. The C-O and O-H stretching vibrations in Alcohols and](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-117.jpg)
Characterization of IR Spectra Table. The C-O and O-H stretching vibrations in Alcohols and Phenol Compound Phenols 3 - OH 2 - OH 1 - OH 2020/11/22 1100 1070 C-O stretch 1220 1150 1100 1050 1100 1070 O-H stretch 3610 3620 3630 3640 1050 1017 117
![Characterization of IR Spectra E Ethers CO stretch 1300 1000 phenyl vinyl Characterization of IR Spectra E. Ethers C-O stretch, 1300 ~ 1000 phenyl & vinyl](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-118.jpg)
Characterization of IR Spectra E. Ethers C-O stretch, 1300 ~ 1000 phenyl & vinyl ethers, shift to higher frequency (increase of double bond character) 1250 (asy), 1040 (sy). Epoxides, 3 bands (1250, 950~815, 850~750) 2020/11/22 118
![Characterization of IR Spectra F Carbonyl compounds 1810 1800 1760 acid chloride Anhydride anhydride Characterization of IR Spectra F. Carbonyl compounds 1810 1800 1760 acid chloride Anhydride anhydride](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-119.jpg)
Characterization of IR Spectra F. Carbonyl compounds 1810 1800 1760 acid chloride Anhydride anhydride (band 1) (band 2) 2020/11/22 1735 1725 1710 ester ketone aldehyde carboxylic acid 1690 amide 119
![Characterization of IR Spectra F1 Factors affect CO vibration 1 Conjugated effects a bunsaturated Characterization of IR Spectra F-1. Factors affect C=O vibration 1. Conjugated effects. a, b-unsaturated,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-120.jpg)
Characterization of IR Spectra F-1. Factors affect C=O vibration 1. Conjugated effects. a, b-unsaturated, 30 cm-1 to lower freq. 1715 1690 2020/11/22 1725 1700 1710 1680 120
![Characterization of IR Spectra 2 Ring size effects 1715 1745 20201122 1715 1780 1735 Characterization of IR Spectra 2. Ring size effects 1715 1745 2020/11/22 1715 1780 1735](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-121.jpg)
Characterization of IR Spectra 2. Ring size effects 1715 1745 2020/11/22 1715 1780 1735 1770 1690 1705 121
![Characterization of IR Spectra 3 Alphasubstitution effects Axial Cl 1725 20201122 Equatorial Cl Characterization of IR Spectra 3. Alpha-substitution effects Axial Cl ~ 1725 2020/11/22 Equatorial Cl](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-122.jpg)
Characterization of IR Spectra 3. Alpha-substitution effects Axial Cl ~ 1725 2020/11/22 Equatorial Cl ~ 1750 122
![Characterization of IR Spectra 4 Hydrogen Bonding Effects 1680 20201122 123 Characterization of IR Spectra 4. Hydrogen Bonding Effects 1680 2020/11/22 123](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-123.jpg)
Characterization of IR Spectra 4. Hydrogen Bonding Effects 1680 2020/11/22 123
![Characterization of IR Spectra 5 Cyclic ketones 1815 1780 1745 1715 1705 Ring strain Characterization of IR Spectra 5. Cyclic ketones 1815 1780 1745 1715 1705 Ring strain](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-124.jpg)
Characterization of IR Spectra 5. Cyclic ketones 1815 1780 1745 1715 1705 Ring strain 2020/11/22 124
![Characterization of IR Spectra 6 Carboxylic Acids OH stretch very broad strongly Hbond 3400 Characterization of IR Spectra 6. Carboxylic Acids O-H stretch, very broad (strongly H-bond) 3400](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-125.jpg)
Characterization of IR Spectra 6. Carboxylic Acids O-H stretch, very broad (strongly H-bond) 3400 ~ 2400 C=O stretch, broad, 1730 ~ 1700 C-O stretch, 1320 ~ 1210 (m) 2020/11/22 125
![Characterization of IR Spectra 7 Esters RCOOR CO stretch 1735 a conjugation at the Characterization of IR Spectra 7. Esters (R-C(=O)-O-R’) C=O stretch, 1735 a. conjugation at the](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-126.jpg)
Characterization of IR Spectra 7. Esters (R-C(=O)-O-R’) C=O stretch, 1735 a. conjugation at the R part: ν shift to the right b. conjugation with O at R’ ν part: shift to the left c. ring strain (lactones): ν shift to the left C-O stretch, two or more bands, one stronger and broader, 1300 ~ 1000 2020/11/22 126
![Characterization of IR Spectra Table The general effects of a bunsaturation or aryl Substitution Characterization of IR Spectra Table. The general effects of a, b-unsaturation or aryl Substitution](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-127.jpg)
Characterization of IR Spectra Table. The general effects of a, b-unsaturation or aryl Substitution and conjugation with oxygen on the C=O vibrations 1770 2020/11/22 1735 1720 127
![Characterization of IR Spectra Table The Effects of Ring Size a bunsaturation and Conjugation Characterization of IR Spectra Table. The Effects of Ring Size, a, b-unsaturation, and Conjugation](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-128.jpg)
Characterization of IR Spectra Table. The Effects of Ring Size, a, b-unsaturation, and Conjugation with Oxygen in the C=O Vibrations in Lactones 1735 1770 1720 1760 1750 1800 1820 2020/11/22 128
![Characterization of IR Spectra 8 Amides CO stretch 1670 1640 NH stretch 1 Characterization of IR Spectra 8. Amides C=O stretch, 1670 ~ 1640 N-H stretch (1](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-129.jpg)
Characterization of IR Spectra 8. Amides C=O stretch, 1670 ~ 1640 N-H stretch (1 and 2 ), 3500, 3100 N-H bending, 1640 ~ 1550 ~ 1660 2020/11/22 ~ 1705 ~ 1745 129
![Characterization of IR Spectra 9 Acid Chlorides CO stretch at 1800 conjugation moves Characterization of IR Spectra 9. Acid Chlorides C=O stretch at ~ 1800 conjugation moves](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-130.jpg)
Characterization of IR Spectra 9. Acid Chlorides C=O stretch at ~ 1800 conjugation moves to the right 10. Anhydrides C=O stretch, two bands, 1830~1800 & 1775~1740 ring strain moves to the left C-O stretch, 1300 ~ 900 2020/11/22 130
![Characterization of IR Spectra G Amines NH stretch 35003300 1 2 bands 2 Characterization of IR Spectra G. Amines N-H stretch, 3500~3300 1 -, 2 bands; 2](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-131.jpg)
Characterization of IR Spectra G. Amines N-H stretch, 3500~3300 1 -, 2 bands; 2 -, 1 band weak, aliphatic amines stronger, aromatic amines N-H bend, 1640~ 1560 2 -, near 1500 N-H oop bending, near 800 C-N stretch, 1350 ~ 1000 2020/11/22 131
![Characterization of IR Spectra H Nitriles Isocyanates and Imines C N stretch sharp Characterization of IR Spectra H. Nitriles, Isocyanates and Imines -C N stretch, sharp ~](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-132.jpg)
Characterization of IR Spectra H. Nitriles, Isocyanates and Imines -C N stretch, sharp ~ 2250 -N=C=O a broad, intense band ~ 2270 -N=C=S a broad, intense band ~ 2125 -C=N- in imine or oxime 1690 -1640 C C give much weak band at ~ 2250 region. 2020/11/22 132
![Characterization of IR Spectra J Nitro Compounds NO stretch two strong bands 1600 Characterization of IR Spectra J. Nitro Compounds N=O stretch, two strong bands, 1600 ~](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-133.jpg)
Characterization of IR Spectra J. Nitro Compounds N=O stretch, two strong bands, 1600 ~ 1500 & 1390 ~ 1300 Nitroalkanes: ~ 1550, 1380 Nitroarenes: ~ 1530, 1350 Nitroso (R-N=O) one band, 1600 ~ 1500 2020/11/22 133
![Characterization of IR Spectra J1 Carboxylate Salts RCOOasym 1600 s sym 1400 s J2 Characterization of IR Spectra J-1. Carboxylate Salts, RC(=O)-Oasym ~1600 (s) sym ~1400 (s) J-2.](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-134.jpg)
Characterization of IR Spectra J-1. Carboxylate Salts, RC(=O)-Oasym ~1600 (s) sym ~1400 (s) J-2. Amine Salts 2020/11/22 N-H stretch (broad), 3300 ~ 2600 N-H bend, 1610 ~ 1500 (s) 1 (two bands), 1610, 1500 2 (one band), 1610 ~ 1550 134
![Characterization of IR Spectra K Sulfur Compounds Mercaptans SH stretch 2550 w Sulfides Characterization of IR Spectra K. Sulfur Compounds Mercaptans S-H stretch, ~ 2550 (w) Sulfides,](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-135.jpg)
Characterization of IR Spectra K. Sulfur Compounds Mercaptans S-H stretch, ~ 2550 (w) Sulfides, R-S-R Sulfoxides, R-S(=O)-R S=O stretch, ~1050 (s) Sulfones, RSO 2 R S=O 1300 (s), 1150 (s) Sulfates RSO 3 R S=O 1375(s), 1200(s) S-O 1000~750 Sulfonamides RSO 2 NH 2, RSO 2 NHR S=O 1325 (s), 1140 (s) N-H 3350, 3250 (1 ) 3250 (2 ) 2020/11/22 135
![Characterization of IR Spectra L Alkyl and Aryl Halides Fluorides CF stretch 14001000 s Characterization of IR Spectra L. Alkyl and Aryl Halides Fluorides C-F stretch, 1400~1000 (s)](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-136.jpg)
Characterization of IR Spectra L. Alkyl and Aryl Halides Fluorides C-F stretch, 1400~1000 (s) Chlorides C-Cl stretch, 800~ 600 (s) CH 2 -Cl bend (wagging), 1300 ~ 1200 Bromides/Iodides C-Br/C-I stretch, ~ 660 out of range CH 2 -Br/CH 2 -I bend (wagging), 1250 ~ 1150 2020/11/22 136
![Infrared Sources and Transducers Infrared sources An inert solid with continuous radiation at heated Infrared Sources and Transducers Infrared sources: An inert solid with continuous radiation at heated](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-137.jpg)
Infrared Sources and Transducers Infrared sources: An inert solid with continuous radiation at heated temperature: 1500 ~ 2000 K. Range of radiation intensity: 5000 ~ 670 cm-1 (2 ~ 15 m. M) 2020/11/22 137
![1 The Nernst Glower temperature 1200 2200 K 2 The Globar Source a 1. The Nernst Glower temperature: 1200 ~ 2200 K 2. The Globar Source a](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-138.jpg)
1. The Nernst Glower temperature: 1200 ~ 2200 K 2. The Globar Source a silicon carbide rod electrically heated (1300 ~ 1500 K) 2020/11/22 138
![Sample Handling Techniques n Neat liquids 一滴樣品夾於二鹽片rocksalt plate間厚 度約為 0 01 mm a Sample Handling Techniques n Neat liquids: 一滴樣品夾於二鹽片(rock-salt plate)間(厚 度約為 ≦ 0. 01 mm), a](https://slidetodoc.com/presentation_image_h/87276d482687613a49238397fcc2da38/image-139.jpg)
Sample Handling Techniques n Neat liquids: 一滴樣品夾於二鹽片(rock-salt plate)間(厚 度約為 ≦ 0. 01 mm), a neat spectrum obtained. 一般 僅適合用於定性的分析. n Solids: n n KBr pellet: 2 ~ 5 mg sample, mixing with 100~150 mg of powdered KBr, pressing with pressure of 5 ~ 10 Ton to give a transparent disc. n KBr is hygroscopic, weak OH band at 3450 cm-1 appeared Nujol mull: grinding the sample with mineral oil (Nujol) to create a suspension and placed between salt plates n Solutions: compound dissolved in common solvents, ex. CS 2, CCl 4, CHCl 3, dioxane, cyclohexane, benzene. 2020/11/22 139
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