1. S TRUCTURE D ETERMINATION AND CH···F I NTERACTIONS IN H 2 C=CHF···H 2 C=CF 2 B Y F OURIER - T RANSFORM M ICROWAVE S PECTROSCOPY Rachel E. Dorris, Rebecca A. Peebles, Sean A. Peebles Department of Chemistry, Eastern Illinois University, Charleston, IL 61920

2. CH···F I NTERACTIONS 2 Christenholz, et al., J. Mol. Spec. 280 (2012) 61. 2.764(5) Å 3.011(3) Å chlorofluoromethane (CFM)··· vinyl fluoride (VF) Christenholz, et al., J. Phys. Chem. A 118 (2014) 1610. 2.83(4) Å 2.521(27) Å difluoromethane (DFM)··· vinyl fluoride (VF) difluoroethylene (DFE)··· HF Leung, et al., J. Chem. Phys. 131 (2009) 204301. 1.9893(4) Å 2.7825(3) Å vinyl fluoride (VF)··· HF Cole, et al., Chem. Phys. Lett. 400 (2004) 419. 1.892(14) Å 2.734 Å vinyl fluoride (VF)··· difluoroethylene (DFE) TOP SIDE TOP

3. A B I NITIO S TRUCTURES VF···DFE 3 Perpendicular (side)Parallel (top) A / MHz6627.95284.6 B / MHz837.8884.8 C / MHz743.8758.0 µ a / D 0.841.60 µ b / D 0.100.04 µ c / D 0.010.02 ΔE / cm -1 038 Gaussian 03: MP2/6-311++G(2d,2p)

4. E XPERIMENTAL H 2 C=CHF···H 2 C=CF 2 Scanned on 480 MHz CP-FTMW 7.5 – 19 GHz, 2000 shots Sample: ~1% each of vinyl fluoride and 1,1- difluoroethylene in He/Ne in 1 L tank – delivered at ~2.5 bar Cavity FTMW Confirmed assigned transitions from scan Measured four 13 C isotopes in natural abundance 4

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6. H 2 C 2 HF··· H 2 C 2 F 2 H 2 13 CCHF··· H 2 C 2 F 2 H 2 C 13 CHF··· H 2 C 2 F 2 H 2 C 2 HF··· H 2 13 CCF 2 H 2 C 2 HF··· H 2 C 13 CF 2 A / MHz6601.140(94)6565.65(47)6590.7(10)6448.41(70)6603.42(71) B / MHz833.33356(13)815.55741(37)825.69515(56)830.42840(63)828.80426(48) C / MHz744.02168(12)729.43341(40)737.82832(58)739.75531(54)740.40711(72) Δ J / kHz0.9088(20)0.9088 Δ JK / kHz10.891(19)10.891 Δ K / kHz δ J / kHz0.0485(20)0.0485 N3791099 RMS / kHz0.975.14.33.85.2 κ −0.9695−0.9705−0.9700−0.9682−0.9698 P cc / u Å 2 1.880(1)1.904(3)1.895(1)1.889(5)1.866(5) S PECTROSCOPIC C ONSTANTS N ORMAL AND I SOTOPIC 6 PerpendicularParallel A / MHz6627.95284.6 B / MHz837.9884.8 C / MHz743.8758.0

7. D IPOLE M OMENTS 7 PerpendicularParallel µ a / D0.841.60 µ b / D0.100.04 µ c / D0.010.02 a b μ a = 0.9002(18) D μ a = 0.84 D μ b = 0.0304(80) D μ b = 0.10 D Experiment Ab initio QSTARK: Kisiel, et al., Chem. Phys. Lett., 325, (2000), 523. Projected µ a = 0.80 D Induced dipole ~0.1 D

8. S TRUCTURE D ETERMINATION 8 Ab initio Inertial fit 2.43 Å 2.463(16) Å 2.52 Å 2.496(9) Å 152.3° 150.8(11)° 138.6° 143.02(19)° Adjusted Parameters R (C 1, C 4 )5.475(12) Å 7.220(66)° 85.01(52)° 1 2 3 4 Structure fit used A and B rotational constants Tried all pairs of rotational constants Many ways of building the structure Varied parameters between carbon atoms Close to ab initio structure Z. Kisiel, J. Mol. Spectrosc. 218, 58-67 (2003).

9. K RAITCHMAN C OORDINATES 9 Inertial fit Kraitchman Literature R (C 1, C 3 ) 4.160(12) Å 4.179(5) Å 1.559(23) Å 1.315(1) Å 1.306(3)Å 1.329(6) Å Lide, D. R.; Christenson, D.; Spectrochem. Act. 17 (1961) 665. Laurie, V. W.; Pence, D. T.; J. Chem. Phys. 38 (1963) 2693. a b 1 2 3 4

10. C OMPARISON WITH OTHER COMPLEXES 10 2.463(16) Å 2.496(9) Å VF···DFE Binding Energies E B (kJmol -1 ) # of “interactions” VF···CFM 8.66(4)3 VF···DFM 9.1(3)3 VF···DFE 5.3(2)2 2.764(5)Å 3.011(3)Å VF···CFM 2.83(4) Å 2.521(27) Å VF···DFM Pseudo diatomic model Millen, D. J.; Can. J. Chem. 63 (1985) 1477. Balle, T. J.; Campbell, E. J.; Keenan, M. R.; Flygare, W. H. A.; J. Chem. Phys. 72 (1980) 922.

11. F UTURE W ORK Ab initio BSSE ZPE Very dense remaining spectrum Cut VF monomer, DFE···Ne, water dimer Other VF···DFE dimer VF dimer, VF···Ne, VF···H 2 O, DFE···H 2 O 11

12. A CKNOWLEDGMENTS NSF RUI program – grant CHE-1214070. Previous group members: Ashley Anderton, Cori Christenholz, Anu Akmeemana, Nate Ulrich Current group members: Seri Kamari, Samee Dikkumbura 12

13. 13 2.463(16) Å 2.496(9) Å 150.82(105)° 143.02(19)° VF···DFE 2.764(5)Å 3.011(3)Å 95.37(4)° 125.22(12)° VF···CFM 2.83(4) Å 2.521(27) Å 90.6(3)° 124.2(7)° VF···DFM k s (Nm -1 ) VF···CFM 5.88(2) VF···DFM 6.8(1) VF···DFE 3.19(6)

14. 14 2.463(16) Å 2.496(9) Å 150.82(105)° 143.02(19)° VF···DFE difluoroethylene (DFE)··· HF Leung, et al., J. Chem. Phys. 131 (2009) 204301. 1.9893(4) Å 2.7825(3) Å 122.41° vinyl fluoride (VF)··· HF Cole, et al., Chem. Phys. Lett. 400 (2004) 419. 1.892(14) Å 2.734 Å 121.4°

15. 15 Frequency (MHz) 414313 6128.4651 423322 6308.0444 422321 6318.3092 413312 6485.6424 515414 7658.55385 505404 7865.8217 524423 7883.62167 533432 7888.79627 532431 7888.95085 523422 7904.12183 514413 8104.9103 616515 9187.33327 606505 9427.5504 625524 9458.2384 634533 9467.62735 633532 9468.0389 624523 9494.03373 615514 9722.71153 717616 10714.58017 707606 10983.1712 726625 11031.7072 735634 11046.9789 734633 11047.9047 725624 11088.76975 716615 11338.70853 818717 12240.09277 808707 12531.84085 827726 12603.8386 836735 12626.88235 835734 12628.7319 826725 12688.9617 817716 12952.54172 919818 13763.68935 928827 14174.43843 927826 14295.09516 918817 14563.83397 100 909 15605.7119

16. S CHEMATIC OF M ICROWAVE C IRCUIT AFG3251 Arbitrary Function Generator DC-240 MHz HP8673G MW Synthesizer 2.0-26.0 GHz Amp RF amp Tektronix TDS5054B 500 MHz Oscilloscope Vacuum chamber LNA Molecular expansion Chirp 16

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18. 18 VoltageFrequency 404303806006298.9263 4043038666102.20 4043038666134.66298.9783 40430386661676299.011 4043038666199.56299.0445 4043038666231.96299.0895 4043038666264.36299.1387 4043038666296.76299.1956 4043038666329.26299.2461 404303846406298.9263 4043038464102.20 4043038464134.66298.9443 40430384641676298.9471 4043038464199.56298.9538 4043038464231.96298.9636 4043038464264.36298.9764 4043038464296.76298.9892 4043038464329.26299.0011 414313806006128.4656 4143138262102.26128.4867 4143138262134.66128.4976 41431382621676128.513 4143138262199.56128.5337 4143138262231.96128.5594 4143138262264.36128.5883 4143138262296.76128.6186 4143138262329.26128.6569 414313806006128.4656 4143138464102.26128.5566 4143138464134.66128.6279 41431384641676128.7158 4143138464199.56128.8273 4143138464231.90 4143138464264.30 4143138464296.70 4143138464329.20 413312846406485.6422 4133128464102.26485.5702 4133128464134.66485.5115 41331284641676485.4385 4133128464199.56485.3419 VoltageFrequency 4133128464231.90 4133128464264.30 4133128464296.70 4133128464329.20 413312826206485.6422 4133128262102.26485.6114 4133128262134.66485.5974 41331282621676485.5737 4133128262199.56485.5462 4133128262231.96485.517 4133128262264.36485.4503 4133128262296.76485.4189 4133128262329.26485.3733 5054041088807865.821 50540410888102.20 50540410888134.60 505404108881670 50540410888199.57865.8881 50540410888231.97865.9136 50540410888264.37865.942 50540410888296.77865.9743 50540410888329.27866.0115 5154141088807658.5544 51541410888102.20 51541410888134.67658.7004 515414108881677658.7745 51541410888199.50 51541410888231.90 51541410888264.30 51541410888296.70 51541410888329.20 5154141068607658.5544 51541410686102.20 51541410686134.67658.6328 515414106861677658.6776 51541410686199.57658.7267 51541410686231.97658.7936 51541410686264.30 51541410686296.70 51541410686329.20 81 lines read in 45 lines in the fit

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