CHARACTERIZATION OF THE TRIFLUOROACETIC ANHYDRIDE MONOMER BY MICROWAVE

CHARACTERIZATION OF THE TRIFLUOROACETIC ANHYDRIDE MONOMER BY MICROWAVE SPECTROSCOPY (AND MORE!) Nathan Love, Anna Huff, CJ Smith, Ken Leopold Department of Chemistry, University of Minnesota June 20 th, 2019

2 PAST WORK: CARBOXYLIC SULFURIC ANHYDRIDES + H 2 O Carboxylic Acid + Sulfur Trioxide Carboxylic Sulfuric Anhydride -H -CH 3 R Groups: -CF 3 -C≡CH -CHCH 2 R. Mackenzie, C. Dewberry, K. Leopold. Science. 2015, 349, 58. A. Huff, R. Mackenzie, C. J. Smith, K. Leopold. J. Phys. Chem. 2017, 121, 30. C. J. Smith, A. Huff, R. Mackenzie, K. Leopold. J. Phys. Chem. 2017, 121, 47. + Carboxylic Acid + Sulfuric Acid

3 ASA MONOHYDRATE + H 2 O Acetic Sulfuric Anhydride 1 (ASA) 1 A. 2 C. Huff, R. Mackenzie, C. J. Smith, K. Leopold. J. Phys. Chem. 2017, 121, 30. J. Smith, A. Huff, R. Mackenzie, K. Leopold. J. Phys. Chem. 2018, 122, 18. ASA-Water Complex 2

4 CARBOXYLIC ANHYDRIDES Carboxylic Anhydride R Groups: -H -CH=CH-C 6 H 4 -CH 3 & -H-CF=CF-CH 2 -CF 3 -CH 2 CCH 2 -CH 2 CHCH 3 S. Vaccani, A. Bauder, and Hs. H. Günthard, Chem. Phys. Lett. 35 (1975) 457. J. L. Alonso, M. R. Pastrana, J. Pelaez, and A. Arauzo, Spectrochimica Acta. 39 A (1983) 215. A. Bauder, Mol. Phys. 111 (2013) 1999. G. Wu, S. Shlykov, C. V. Alsenoy, H. J. Geise, E. Sluyts, and B. J. Van der Veken, J. Phys. Chem. 99 (1995) 8589. M. Pejlovas, M. Sun, and S. G. Kukolich, J. Mol. Spectrosc. 299 (2014) 43. T. J. Mc. Mahon, J. R. Bailey, and R. G. Bird, J. Mol. Spectrosc. 347 (2018) 35.

5 TRIFLUOROACETIC ANHYDRIDE (TFAA) Sideview:

6 INTERNAL MOTION IN TFAA? 0. 20 kcal/mol

ty Hz increments on FTMW INSTRUMENTATION • Broadband • >30 k. Hz re • Lower Sen

8 INTEGRATING ISDDFASF Measure Average Find Peaks Analyze Goals: 1 Improve Efficiency Chirp-o-matic GUI 2 Increase Ease

9 CHIRP-O-MATIC Measure Average Find Peaks Analyze Collect Data Initialize Input: • Collection Parameters • Save Location Save Time Domain Auto. Average Chirp-o-matic User Interface Fourier Transform Terminate Output: • Saved Data Files • Averaged FT Data Save FT Data

10 DAPPERS: A NEW PEAK FINDER Experimental Spectrum Data Analysis Package for Productive and Enthusiastic Rotational Spectroscopists 6 GHz 9 GHz 12 GHz 15 GHz 18 GHz

CHIRPING FOR TFAA 6 GHz 9 GHz 12 GHz 1. 34 atm 0. 5% TFAA-Ar 15 GHz 11 18 GHz

R-BRANCH KP: 0 1 J=9 J = 10 J = 11 J = 12 J = 13 J = 14 J = 15 J = 16 J = 17 J = 18 J = 19 J = 20 J = 21 12 J = 22

R-BRANCH KP: 1 0 J=7 J=8 J=9 J = 10 J = 11 J = 12 J = 13 J = 14 J = 15 J = 16 J = 19 J = 20 J = 18 J = 17 J = 21 13 J = 22

R-BRANCH KP: 2 1 14

R-BRANCH KP: 3 2 15

R-BRANCH KP: 4 3 16

R-BRANCH: A CLOSER LOOK Chirp Cavity Predicted Splitting: 66 k. Hz Observed Splitting: 68 k. Hz 17

R-BRANCH KP: 5 4 18

FULL R-BRANCH 19

20 Q-BRANCH KP: 5 4 Experimental 11, 055 MHz 11, 110 MHz Fit 7254 k. Hz 4227 k. Hz 2364 k. Hz 20 k. Hz *5 k. Hz *1 k. Hz 1265 k. Hz 637 k. Hz 297 k. Hz 114 k. Hz 51 k. Hz *Predicted Splitting

21 Q-BRANCH KP: 3 2 Experimental 6000 MHz Fit 6250 MHz 6500 MHz

22 TFAA: P-BRANCH *4536 J=4 KP = 4 4563 5364 5387 J = 16 Kp = 8 J = 13 Kp = 7 J = 10 J = 7 Kp = 6 Kp = 5 6185 6215 J = 15 Kp = 8 J=6 Kp = 5 J = 12 Kp = 7 J=9 Kp = 6 J = 14 Kp = 8 J=5 Kp = 5 J=8 Kp = 6 J = 11 Kp = 7 J = 17 Kp = 9 7013 7032 J = 13 Kp = 8 J=7 Kp = 6 J = 10 Kp = 7 *x-axis units in MHz

23 TFAA CONSTANTS

DAPPERS: AUTOMATIC FITTING ALGORITHM 24 Experimental Spectrum 12 GHz Predicted Spectrum* *Based on M 06 -2 X calculations 15

DAPPERS: AUTOMATIC FITTING ALGORITHM 25 200 MHz User Defined Initial Window Algorithm: 1) Check for peaks within user specified window about lower transition 12 GHz 15 GHz 2) Apply Ratio Test: 12174 MHz 12374 MHz

DAPPERS: AUTOMATIC FITTING ALGORITHM 26 Algorithm: 1) Check for peaks within user specified window about lower transition 12 GHz 2) Apply Ratio Test: 3) Repeat N times 15 GHz

DAPPERS: AUTOMATIC FITTING ALGORITHM 27 10 MHz User Defined Window Algorithm: 1) Check for peaks within user specified window about lower transition 12 GHz 15 GHz 2) Apply Ratio Test: 12952. 7 MHz 3) Repeat N times 12962. 7 MHz

DAPPERS: AUTOMATIC FITTING ALGORITHM 28 RMS=4 k. Hz* Algorithm: 1) Check for peaks within user specified window about lower transition 12 GHz 2) Apply Ratio Test: 3) Repeat N times *Fit to rotational constants A, B, and C 15 GHz

DAPPERS: AUTOMATIC FITTING ALGORITHM Algorithm: 1) Check for peaks within user specified window about lower transition 2) Apply Ratio Test: Compatible with: • a, b, and c-type spectra • R, Q, and P branch transitions • Fit several ongoing projects • TFAA-H 2 O 3) Repeat N times 29

30

31 SUMMARY • The TFAA monomer was characterized • No evidence of large amplitude motion was observed • Development of Chirp-o-matic and DAPPERS packages The spectroscopist’s one stop shop! • Continue to study hydration of anhydrides

32 ACKNOWLEDGEMENTS Dr. Ken Leopold CJ Smith Anna Huff

33

DAPPERS: AUTOMATIC FITTING ALGORITHM = Match, continue searching = No Match, stop searching Algorithm: 1) Check for peaks within user specified window about lower transition 2) Apply Ratio Test: 3) Repeat N times = Fit of length N (5 in this case) 1 2 3 4 34

35 FUTURE WORK: TFAA HYDRATES Lower by 1. 56 kcal/mol TFAA Monohydrate TFAA Dihydrate

36 COMPLETED WORK: PEAK FINDER List of Peaks Spectrum Peak Finder Program Coarse Mode: 100 MHz Fine Mode: 520 k. Hz Window Average Intensity + Coarse Sensitivity Value Window Threshold

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38 INTERNAL ROTATION

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R-BRANCH K: 0 1 40

R-BRANCH K: 1 0 41

R-BRANCH K: 2 1 42

R-BRANCH K: 3 2 43

R-BRANCH K: 4 3 44

R-BRANCH K: 5 4 45