Vibrational Signatures of Large Amplitude Motions for the

Vibrational Signatures of Large Amplitude Motions for the Shackled Hydronium Ion Nested in 18 -Crown-6 Ether Using D 2 Tagging Chinh H. Duong, Fabian S. Menges, Stephanie M. Craig, Conrad T. Wolke, Mark A. Johnson 71 st International Symposium on Molecular Spectroscopy - MH 12 June 20, 2016 1

Capturing the Interlocking Mechanics of Molecular Ionophores Chinh H. Duong, Fabian S. Menges, Stephanie M. Craig, Conrad T. Wolke, Mark A. Johnson 71 st International Symposium on Molecular Spectroscopy - MH 12 June 20, 2016 2

What is an Ionophore? A chemical species that binds reversibly to an ion and transports it across a membrane. Docking Transport Conformation change Release Conformation change 3

What is an Ionophore? A chemical species that binds reversibly to an ion and transports it across a membrane. Docking Transport Conformation change Release Conformation change Investigate spectral changes associated with distortions in the scaffolding due to ion docking. Ganim, Z. ; Tokmakoff, A. ; Vaziri, A. , New J Phys 2011, 13. 4

What is an Ionophore? A chemical species that binds reversibly to an ion and transports it across a membrane. Docking Transport Conformation change Release Conformation change Investigate spectral changes associated with distortions in the scaffolding due to ion docking. Model Case: Ions in 18 -Crown-6 Ether Ganim, Z. ; Tokmakoff, A. ; Vaziri, A. , New J Phys 2011, 13. 5

What’s been done? 6

IRMPD Studies B 3 LYP/cc-pvdz Hurtado, P. ; Gamez, F. ; Hamad, S. ; Martinez. Haya, B. ; Steill, J. D. ; Oomens, J. , Journal of Physical Chemistry A 2011, 115 (25), 7275 -7282. 7

IRMPD Studies B 3 LYP/cc-pvdz Hurtado, P. ; Gamez, F. ; Hamad, S. ; Martinez. Haya, B. ; Steill, J. D. ; Oomens, J. , Journal of Physical Chemistry A 2011, 115 (25), 7275 -7282. 8

IRMPD Studies C-O stretches • C-O stretches of the 18 crown-6 ether respond to the symmetry break that occurs when the molecular ions bind to the crown ether. • Increasing the interaction strength of the ion with the 18 -crown-6 ether seems to increase the splitting between the C-O stretches. Hurtado, P. ; Gamez, F. ; Hamad, S. ; Martinez. Haya, B. ; Steill, J. D. ; Oomens, J. , Journal of Physical Chemistry A 2011, 115 (25), 7275 -7282. 9

Tuning the Interaction Strength 18 -Crown-6 • H 3 O+ 18 -Crown-6 • NH 4+ 2. 85 Å 2. 74 Å Complex X(O, N)-O Qualitative distance (Å) Interaction Strength 18 -Crown-6 • H 3 O+ 2. 74 Strong 18 -Crown-6 • NH 4+ 2. 86 Weaker 18 -Crown-6 • NH 3 CH 3+ 2. 87 Weakest 18 -Crown-6 • NH 3 CH 3+ 2. 87 Å *All computed with B 3 LYP/cc-pvdz 10

Tuning the Interaction Strength 18 -Crown-6 • H 3 O+ 18 -Crown-6 • NH 4+ 2. 85 Å 2. 74 Å Complex X(O, N)-O Qualitative distance (Å) Interaction Strength 18 -Crown-6 • H 3 O+ 2. 74 Strong 18 -Crown-6 • NH 4+ 2. 86 Weaker 18 -Crown-6 • NH 3 CH 3+ 2. 87 Weakest 18 -Crown-6 • NH 3 CH 3+ 2. 87 Å *All computed with B 3 LYP/cc-pvdz 11

Cryogenic Ion Photofragmentation Mass Spectrometer Temperature Controlled Ion Trap Mounted to He Cryostat Wiley. Mc. Laren TOF Reflectron Ion Optics DC-Turning Quad 2 m Flight Tube Differential Aperture Heated Capillary ESI Needle MCP Detector Signal Skimmers Predissociation Yield (a. u. ) RF-Ion Guides Tunable IR (600 -4500 cm-1) Laser System 800 1200 1600 2000 Photon Energy (cm-1) 2400 Time of Flight, ms 12

18 -Crown-6 Ether • NH 4+ D 2 tag C-O stretches NH 3+ bend C-H stretches B 3 LYP/cc-pvdz Fragmentation Yield (a. u. ) Predissociation Yield (a. u. ) librations IRMPD at room temp 1 800 1200 1600 2000 Photon Energy (cm-1) 1. Hurtado, P. ; Gamez, F. ; Hamad, S. ; Martinez-Haya, B. ; Steill, J. D. ; Oomens, J. , Journal of Physical Chemistry A 2011, 115 (25), 7275 -7282. 13

18 -Crown-6 Ether • H 3 O+ D 2 tag librations C-H bends H 3 O+ association band H 3 O+ bend B 3 LYP/cc-pvdz Yield (a. u. ) Fragmentation Predissociation Yield (a. u. ) C-O stretches IRMPD – at room temp 1 800 1200 1600 2000 2400 Photon Energy (cm-1) 1. Hurtado, P. ; Gamez, F. ; Hamad, S. ; Martinez-Haya, B. ; Steill, J. D. ; Oomens, J. , Journal of Physical Chemistry A 2011, 115 (25), 7275 -7282. 14

Predissociation Yield (a. u. ) Predissociation Spectra of 18 -Crown-6 Ether with Various Ions C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 15

Predissociation Yield (a. u. ) Predissociation Spectra of 18 -Crown-6 Ether with Various Ions NH 3+ stretch C-O stretches NH 3 CH 3+ NH 3 CH 3 rocking libration NH 3 CH 3+ umbrella C-H stretches NH 3 CH 3+ bend C-H stretches C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 16

Predissociation Spectra of 18 -Crown-6 Ether with Various Ions Predissociation Yield (a. u. ) NH 4+ C-O stretches NH 4+ stretch C-H stretches NH 4+ bend libration free N-H NH 3+ stretch C-O stretches NH 3 CH 3+ NH 3 CH 3 rocking libration NH 3 CH 3+ umbrella C-H stretches NH 3 CH 3+ bend C-H stretches C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 17

Predissociation Spectra of 18 -Crown-6 Ether with Various Ions H 3 O+ asym stretch C-O stretches C-H stretches H 3 O + libration Predissociation Yield (a. u. ) NH 4+ C-H stretches H 3 O+ bend H 3 O+ association band C-O stretches NH 4+ stretch C-H stretches NH 4+ bend libration free N-H NH 3+ stretch C-O stretches NH 3 CH 3+ NH 3 CH 3 rocking libration NH 3 CH 3+ umbrella C-H stretches NH 3 CH 3+ bend C-H stretches C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 18

Predissociation Spectra of 18 -Crown-6 Ether with Various Ions H 3 O+ asym stretch C-O stretches C-H stretches H 3 O + libration Predissociation Yield (a. u. ) NH 4+ C-H stretches H 3 O+ bend H 3 O+ association band C-O stretches NH 4+ stretch C-H stretches NH 4+ bend libration free N-H NH 3+ stretch C-O stretches NH 3 CH 3+ NH 3 CH 3 rocking libration NH 3 CH 3+ umbrella C-H stretches NH 3 CH 3+ bend C-H stretches C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 19

Predissociation Spectra of 18 -Crown-6 Ether with Various Ions H 3 O+ asym stretch C-O stretches C-H stretches H 3 O + libration Predissociation Yield (a. u. ) NH 4+ C-H stretches H 3 O+ bend H 3 O+ association band C-O stretches NH 4+ stretch C-H stretches NH 4+ bend libration free N-H NH 3+ stretch C-O stretches NH 3 CH 3+ NH 3 CH 3 rocking libration NH 3 CH 3+ umbrella C-H stretches NH 3 CH 3+ bend C-H stretches C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 20

Predissociation Spectra of 18 -Crown-6 Ether with Various Ions H 3 O+ asym stretch C-O stretches C-H stretches H 3 O + libration Predissociation Yield (a. u. ) NH 4+ C-H stretches H 3 O+ bend H 3 O+ association band C-O stretches NH 4+ stretch C-H stretches NH 4+ bend libration free N-H NH 3+ stretch C-O stretches NH 3 CH 3+ NH 3 CH 3 rocking libration NH 3 CH 3+ umbrella C-H stretches NH 3 CH 3+ bend C-H stretches C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 21

Predissociation Spectra of 18 -Crown-6 Ether with Various Ions An enormously broad peak appears! C-O stretches H 3 O + libration Predissociation Yield (a. u. ) NH 4+ C-H stretches H 3 O+ bend H 3 O+ asym stretch C-H stretches H 3 O+ association band C-O stretches NH 4+ stretch C-H stretches NH 4+ bend libration free N-H NH 3+ stretch C-O stretches NH 3 CH 3+ NH 3 CH 3 rocking libration NH 3 CH 3+ umbrella C-H stretches NH 3 CH 3+ bend C-H stretches C-O stretches C-H stretches K+ libration 800 C-H stretches 1200 1600 2000 2400 Photon Energy 2800 (cm-1) 3200 3600 4000 22

2000 Is it a tag effect? H 3 O+ stretch C-H stretches Predissociation Yield (a. u. ) 18 C 6 -H 3 O+ One D 2 Tag H 3 O+ stretch C-H stretches 18 C 6 -H 3 O+ Three D 2 Tag 2400 2800 3200 3600 Photon Energy (cm-1) 4000 23

Different Isomers? 18 -Crown-6 Ether • H 3 O+ • Relative Energy: 0. 13 kcal/mol (44 cm-1) • There is only a 7 cm-1 shift in the O-H stretches of these isomers. Relative Intensity (a. u. ) • This is not enough to account for the O-H stretches spanning 900 cm-1. High Oxygen Position C-O stretches librations C-H bends C-H stretches Low Oxygen Position H 3 O+ asym stretch r. B 3 LYP/cc-p. VDZ 800 1200 1600 2000 2400 2800 Photon Energy (cm-1) 3200 3600 4000 24

tretches How many protons are contributing to the O-D and O-H stretches? H 3 O+ stretch C-H stretches H 3 O+ association band C-H stretches H 3 O+ bend 200 18 C 6 • H 3 O+ Predissociation Yield (a. u. ) H 2 DO+ stretch 1600 18 C 6 • H 2 DO+ D-O stretch HD 2 O+ stretch Wow! A single proton can produce the breadth of the O-H stretching region! 18 C 6 • HD 2 O+ 18 C 6 • D 3 O+ A multiplet structure arises! 2000 2400 2800 3200 Photon Energy (cm-1) 3600 4000 25

Ongoing Research 1. Investigate the origins of the multiplet structure. 2. Explore adaptations to the host (such as dibenzo-18 -crown-6 ether) and observe the effects on the guest ions. H 3 O+ asym stretch C-O stretches Predissociation Yield (a. u. ) 18 C 6 • H 3 C-H stretches O+ C-H stretches H 3 O+ bend libration H 3 O+ association band C-H stretches 18 C 6 • D 3 O+ C-O stretches libration 800 D 3 O+ asym stretch C-H stretches 1200 1600 2000 2400 Photon Energy (cm-1) 2800 3200 3600 4000 26

Acknowledgements Johnson Lab: • Prof. Mark Johnson • Prof. Gary Weddle • Dr. Fabian Menges • Dr. Joe De. Palma • Dr. Conrad Wolke • Olga Gorlova • Stephanie Craig • Patrick Kelleher • Joanna Denton • Nan Yang • Helen Zeng 27