1. The Ohio State University International Symposium on Molecular Spectroscopy 68th Meeting - - June 17-21, 2013 Microwave Spectrum of Hexafluoroisopropanol, comparison with hexafluoroisobutene And its complex with water Abhishek Shahi and E. Arunan Department of Inorganic and Physical Chemistry Indian Institute of Science Bangalore, India

2. Complete study of Hexafluoroisopropanol with all of its C-13 and duterated isotopologues. Comparison with prototype molecules. Microwave study of HFIP-water complex.

3. Interesting properties of HFIP – Rotational Spectroscopic Low vapor pressure and boiling point. Offer different possibility for intermolecular interaction. – Chemist and society Solvent for polymers (e.g. polythene ) Strong affinity for oxygen

4. Two conformers have been reported at room temperature in IR spectra, namely antiperiplaner (ap) and synclinical (sc). IR study: In gas phase, ap conformer is more stable while in liquid phase, sc conformer is more stable. Is it possible to get both conformer with supersonic beam experiment ? H. Schaal, T. Häber, M. Suhm, Hydrogen Bonding in 2-Propanol. The Effect of Fluorination, The Journal of Physical Chemistry A 104 (2000) 265–274. ap sc

5. HFIP (ap) 7F-2C-3C-12F = 0  Low Vib. Freq. = 32 cm -1  = -0.79 HFIB 4F-2C-3C-9F = 23.5  Low Vib. Freq. = 39 cm -1  = -0.81 Bis-trifluoromethyl effect: Doubled Transitions in the rotational spectra of HFIB. Same Behavior: Hexafluoroacetone imine Will Hexafluoroisopropanol show doubling in spectrum ?

6. Pulsed Nozzle Fourier Transform Microwave Spectroscopy. Calculated transitions are very close to experimentally observed lines. 111 Transitions could be fitted in rotational Hamiltonian within experimental uncertainty. There are about 35 unassigned lines but no signature of splitting of any kind.

7. R-b type transitions TransitionsFrequencyO-C 1, 1, 1 <- 0, 0, 03037.46370.0032 2, 1, 2 <- 1, 0, 14902.13800.0017 3, 0, 3 <- 2, 1, 24980.1636-0.0009 3, 1, 3 <- 2, 0, 26709.95310.0011 4, 0, 4 <- 3, 1, 37059.14400.0001 2, 2, 1 <- 1, 1, 07247.70300.0046 2, 2, 0 <- 1, 1, 17379.3140-0.0001 7, 2, 6 <- 6, 3, 38056.2860-0.0046 4, 1, 4 <- 3, 0, 38473.8905-0.0044 3, 2, 2 <- 2, 1, 19112.36720.0041 5, 0, 5 <- 4, 1, 49125.4651-0.0031 7, 2, 5 <- 6, 3, 49134.6363-0.0013 3, 2, 1 <- 2, 1, 29526.6928-0.0010 12, 6, 7 <- 11, 7, 49555.1948-0.0010 12, 6, 6 <- 11, 7, 59555.7447-0.0019 6, 1, 5 <- 5, 2, 49717.86130.0016 8, 2, 7 <- 7, 3, 49808.75530.0011 10, 4, 7 <- 9, 5, 410052.0152-0.0034 10, 4, 6 <- 9, 5, 510114.4290-0.0041 9, 3, 7 <- 8, 4, 410187.74900.0158 5, 1, 5 <- 4, 0, 410213.3467-0.0041 4, 2, 3 <- 3, 1, 210914.93940.0048 6, 0, 6 <- 5, 1, 511161.5053-0.0042 8, 2, 6 <- 7, 3, 511494.2363-0.0042 3, 3, 1 <- 2, 2, 011514.78760.0019 3, 3, 0 <- 2, 2, 111525.25930.0016 4, 2, 2 <- 3, 1, 311789.52210.0030 6, 1, 6 <- 5, 0, 511949.9311-0.0011 7, 1, 6 <- 6, 2, 512011.7074-0.0046 5, 2, 4 <- 4, 1, 312657.34430.0047 7, 0, 7 <- 6, 1, 613159.3272-0.0027 4, 3, 2 <- 3, 2, 113480.15830.0008 4, 3, 1 <- 3, 2, 213533.09250.0014 7, 1, 7 <- 6, 0, 613701.2685-0.0061 9, 2, 7 <- 8, 3, 613913.85620.0191 5, 2, 3 <- 4, 1, 414197.09790.0005 8, 1, 7 <- 7, 2, 614300.8539-0.0047 6, 2, 5 <- 5, 1, 414344.0340-0.0006 8, 0, 8 <- 7, 1, 715120.1191-0.0028 4, 4, 1 <- 3, 3, 015730.2270-0.0085 4, 4, 0 <- 3, 3, 115730.7660-0.0031 Q-b type transitions 6, 3, 3 <- 6, 2, 55771.36110.0014 9, 4, 5 <- 9, 3, 67378.23900.0020 8, 4, 4 <- 8, 3, 57541.1040-0.0006 6, 4, 2 <- 6, 3, 37710.91920.0032 21, 4, 17 <- 21, 3, 187713.06600.0043 5, 4, 1 <- 5, 3, 27745.9150-0.0015 7, 4, 4 <- 7, 3, 57746.39500.0012 8, 4, 5 <- 8, 3, 67748.9930-0.0015 6, 4, 3 <- 6, 3, 47751.8900-0.0022 12, 1, 11 <- 12, 0, 127758.03700.0015 5, 4, 2 <- 5, 3, 37759.89300.0033 4, 4, 0 <- 4, 3, 17763.44700.0084 4, 4, 1 <- 4, 3, 27766.99000.0044 9, 4, 6 <- 9, 3, 77767.3660-0.0005 10, 4, 7 <- 10, 3, 87810.76600.0063 11, 4, 8 <- 11, 3, 97889.2270-0.0032 13, 3, 11 <- 13, 2, 127910.9312-0.0018 12, 4, 9 <- 12, 3, 108012.7315-0.0029 15, 2, 13 <- 15, 1, 148019.7668-0.0026 15, 3, 13 <- 15, 2, 149080.38050.0043 16, 4, 13 <- 16, 3, 149106.5263-0.0097 17, 4, 14 <- 17, 3, 159546.9948-0.0014 12, 5, 7 <- 12, 4, 89610.8610-0.0023 11, 5, 6 <- 11, 4, 79745.28990.0008 13, 5, 9 <- 13, 4, 109826.12950.0038 14, 5, 10 <- 14, 4, 119829.01170.0018 10, 5, 5 <- 10, 4, 69836.57500.0044 12, 5, 8 <- 12, 4, 99841.5585-0.0012 15, 5, 11 <- 15, 4, 129859.8783-0.0013 11, 5, 7 <- 11, 4, 89866.9440-0.0016 10, 5, 6 <- 10, 4, 79895.7021-0.0004 9, 5, 4 <- 9, 4, 59897.08260.0004 9, 5, 5 <- 9, 4, 69923.2200-0.0029 8, 5, 3 <- 8, 4, 49936.4800-0.0002 8, 5, 4 <- 8, 4, 59946.7705-0.0030 7, 5, 3 <- 7, 4, 49965.1802-0.0006 6, 5, 1 <- 6, 4, 29977.4400-0.0001 6, 5, 2 <- 6, 4, 39978.40760.0026 5, 5, 0 <- 5, 4, 19986.91650.0048 5, 5, 1 <- 5, 4, 29987.11250.0059 17, 5, 13 <- 17, 4, 1410046.29490.0022 18, 4, 15 <- 18, 3, 1610051.7417-0.0024 18, 5, 14 <- 18, 4, 1510220.6673-0.0011 21, 5, 17 <- 21, 4, 1811143.6080-0.0018 18, 6, 12 <- 18, 5, 1311178.87050.0006 16, 6, 11 <- 16, 5, 1211894.23630.0015 15, 6, 10 <- 15, 5, 1111946.58140.0015 14, 6, 9 <- 14, 5, 1011998.7516-0.0034 13, 6, 7 <- 13, 5, 812014.4102-0.0020 11, 6, 5 <- 11, 5, 612117.83000.0072 11, 6, 6 <- 11, 5, 712124.1070-0.0002 8, 6, 2 <- 8, 5, 312189.2087-0.0011 8, 6, 3 <- 8, 5, 412189.4432-0.0015 6, 6, 0 <- 6, 5, 112208.2040-0.0072 20, 7, 13 <- 20, 6, 1413708.00220.0032 R-c type transitions 1, 1, 0 <- 0, 0, 03159.1145-0.0014 2, 2, 0 <- 1, 1, 07257.6540-0.0047 2, 2, 1 <- 1, 1, 17369.3510-0.0028 3, 2, 1 <- 2, 1, 19161.73700.0090 4, 1, 3 <- 3, 0, 39686.8711-0.0036 4, 2, 2 <- 3, 1, 211060.10210.0018 3, 3, 0 <- 2, 2, 011515.2949-0.0025 3, 3, 1 <- 2, 2, 111524.74660.0007 4, 2, 3 <- 3, 1, 311644.35780.0044 5, 1, 4 <- 4, 0, 412023.9954-0.0041 5, 2, 3 <- 4, 1, 312984.1168-0.0008 4, 3, 1 <- 3, 2, 113483.73640.0102 4, 3, 2 <- 3, 2, 213529.52390.0015 Q-c type transitions 9, 5, 5 <- 9, 4, 59896.25700.0011 5, 5, 1 <- 5, 4, 19986.8900-0.0209 111 observed transitions of b and c-type only.

8. Absence of a-type transition suggests that the observed spectrum corresponds to ap conformer

9. D : HFIP (OD)  Prepared D : HFIP (OD_CD)  Bought C-13 : HFIP (Side C-13)  Natural Abundance C-13 : HFIP (Center C-13)  Natural Abundance D : HFIP (OD)  Prepared D : HFIP (OD_CD)  Bought C-13 : HFIP (Side C-13)  Natural Abundance C-13 : HFIP (Center C-13)  Natural Abundance Predictions for all the isotopologues are very close to experimental values.

10. HFIP (OD)HFIP(OD_CD)HFIP (C-13) Side HFIP (C-13) CenterA/MHz2066.6444(10)2042.0355(23)2105.0638(18)2099.9217(16) B/MHz1052.74254(91)1046.7717(10)1050.43361(72)1053.43442(63) C/MHz 925.60404(54) 925.2142(10) 929.53229(60) 931.88122(63) D J /kHz 0.0552(55) 0.0486(97) 0.0528(59) 0.0492(57) D JK /kHz 0.442(55) 0.508(74) 0.525(62) 0.481(53) D K /kHz -0.483(71) -0.54(11) -0.411(74) -0.460(60) d 1 /kHz -0.0089(37)-0.0073 d 2 /kHz 0.0059(35)0.0023 RMS0.00560.01250.00750.0057 #N26282217

11. CalculatedHFIPHFIP(OD)HFIP(OD_CD)HFIP (side C-13)HFIP (center C-13) A2098.76512060.54142036.41602098.60492093.6237 B1053.29501051.98121046.10801049.68661052.6644 C931.9870925.2922924.9392929.1385931.4649 Experimental A2105.12172066.64442042.03552105.06382099.9217 B1053.99501052.74251046.77171050.43361053.4344 C932.3396925.6040925.2142929.5323931.8812 Difference A6.46.15.66.56.3 B0.70.80.7 0.8 C0.40.3 0.4 Advantages: Ease in prediction Identification of structure (when many conformers exist)

12. Bond length/Å ExperimentalCalculated r (CM-H2)2.119(1)2.109 r(CM-H1)1.719(1)1.703 r(CM- C2/C3) 1.280(2)1.292 r(CM-C1)0.748(3)0.769 Bond length/Å ExperimentalCalculated r(C1-H1)1.1201.092 r (C1-C2/C3)1.4601.531

13. Question was Will Hexafluoroisopropanol show doubling in spectrum ? Answer is NO Explanation ? Theoretical tools may help - PES scan - NBO Analysis -……… And many other

14. 1 3 2 Energy (cm -1 ) 1 3 1 2 3 Hexafluroisobutene Hexafluroisopropane Why there is no barrier for HFIP ?

15. Donor Acceptor E(2) LP ( 2) O  BD*( 1) C 1- C 2 9.32 kcal/mol LP ( 2) O  BD*( 1) C 1- C 3 9.32 kcal/mol There is no such interaction to weaken the C1-C3 and C1-C2 bond.

16. IR study of HFIP-water complex has been done in condensed phase. Electronic structure calculations give many true minima structures. Interaction of maximum electron density point of HFIP with minimum electron density of water, is most stable structure.

17. Str: 1 Str: 2Str: 3  Fourteen different possibilities have been taken in account.  All converge to these three structure.  Structure 2 results from sc conformers  Structure 3 has very less binding energy.  Structure 1 is believed to exist in supersonic beam.  Other analyses support structure 1.

18. HFIP monomer Number of surface minima: 10 # kcal/mol 1 -8.207319 2 -8.376903 3 -7.293980 4 -7.945753 5-19.398577 6 -8.318290 7 -7.945012 8 -7.292588 9 -8.378746 10 -8.208162 Number of surface maxima: 7 # kcal/mol 1 21.206808 2 38.492303 3 59.887172 4 31.317082 5 38.124459 6 38.440830 7 21.390870 Water monomer Number of surface minima: 1 # kcal/mol 1 -39.856463 Number of surface maxima: 2 # kcal/mol 1 47.382423 2 47.379606 Maximum-minimum interaction (Electron Density value)

19. NBO Result: Donor Acceptor E(2) kcal/mol LP ( 2) O BD*( 1) O - H 17.63 We are expecting doubling in spectrum because of the large amplitude motion of H 2 O. AIM Result: Electron Density at intermolecular BCP= 0.03388 a.u. This Value suggest a very strong Hydrogen bond.

20. O-H----O bond length 1.80 Å, which comes in region of very strong H-bond. Floppiness of complex reduced due to strong complex formation and ab intio calculation prove to be good. For this complex, MP2/6- 311++G(d,p) level theory results are consider as model. Search started for b-type of transitions. Lowest vibrational frequency = 27 cm -1

21. More than 45 Transitions observed for HFIP-water. Both b- and c-type transitions observed. 20 lines could be fitted, but the standard deviation of fit is high (395 kHz). Search for other transitions is in progress. Dipole moment : (a, b, c) = [0.4, 1.7, 1.5]

22. TransitionsFrequency (Exp)Obs - Cal 5 0 5 - 4 1 47401.59000.4282 5 1 5 - 4 0 47403.1100-0.1179 4 4 1 - 3 3 08799.46350.1293 6 0 6 - 5 1 58812.60200.0292 6 1 6 - 5 0 58812.8365-0.0565 4 4 1 - 3 3 18882.65900.061 4 4 0 - 3 3 18915.9150-0.0923 4 3 1 - 3 2 28958.84350.7128 6 2 5 - 5 1 49521.1735-0.7956 7 0 7 - 6 1 610223.1295-0.1396 7 1 7 - 6 0 610223.1685-0.1474 5 4 2 - 4 3 110306.8905-0.1241 5 2 3 - 4 1 310360.5805-0.6253 8 0 8 - 7 1 711634.51000.6995 8 1 8 - 7 0 711634.51000.6929 8 2 7 - 7 1 612333.25100.5244 9 0 9 - 8 1 813044.0270-0.2384 9 1 9 - 8 0 813044.0270-0.2393 10 0 10 - 9 1 914454.4560-0.1715 10 1 10 - 9 0 914454.4560-0.1717 Rot. Const. ExperimentalCalculated A/MHz 1139.6398( 86)1148.2883 B/MHz 984.22827( 99)986.1836 C/MHz 705.38439( 69)710.4890 D J /kHz 0.5807( 51) D JK /kHz -0.000010937( 79) D K /kHz 3.99( 34) RMS /MHz0.395 #N20 b-type transition are more intense than c-type a-type transition could not observed yet. Pickett program used for fitting

23. Complete determination of HFIP monomer spectrum. Reason for no splitting in HFIP transitions is l.p.  overlap between oxygen and C-C bonds. 20 lines for the HFIP-water complex have been observed and further search is in progress.

24. Funding: Indian Institute of Science, Bangalore, India Royal Society of Chemistry (PCCP) for travel grant Indo-French Centre of Pure and Applied Research Department of Science and technology Council of Scientific and Industrial Research