1.  -  and CH-  interactions in the molecular nitrogen- and methane-pyridine complexes Department of Chemistry University of Alberta

2. Valuable prototypes for the  -  and CH-  interactions found in many reactive systems.  Supramolecular structures  DNA  -  stacking and assembly  CH-  attraction in asymmetric hydrogenation reactions MOTIVATION

3. a T. Steiner and G. R. Desiraju Chem. Commun. 8, 891 (1998). b The CH/pi Interaction, by M. Nishio, M. Hirota, and Y. Umezawa (1998). c M. Yamakawa, I. Yamada, R. Noyori, Angew. Chem. Int. Ed., 40, 15,2818 (2001). What is CH-  interaction? A weak noncovalent bond occurring between soft acids and soft bases. But is it a non-conventional weak hydrogen bond? a Is it more like ‘hydrogen bond’ C-H    O? b Fig.1 c Fig.2

4. Hydrogen bonds diagram: G. R. Desiraju, Acc. Chem. Res., 35, 565 -573, (2002). a MATI: K. Shibasaki, A. Fujii, N. Mikami, and S. Tsuzuki, J. Phys. Chem. A 110, 4397 (2006). WEAKLY BOUND N 2 -C 5 H 5 N  1.3 Kcal/mol a CH 4 -C 6 H 6  1.1(1) Kcal/mol Dispersion interaction

5. What are we doing? 15 N 2 - C 5 H 5 NCH 4 - C 5 H 5 N Answers to questions. 1. How do N 2, CH 4 interact with a polar aromatic nitrogen heterocycle? 2. What is the vdW bond distance? -not well measured for CH 4 -C 6 H 6 FTMW

6. MW EXPERIMENTAL RESULTS 15 N 2 - C 5 H 5 N

7. The spectrum of 15 N 2 -C 5 H 5 N. Sample: 0.5% pyridine + 2.5% 15 N 2 + 4 atm. Ne

8. A 1 (  = 0, I = 0) stateB 2 (  = 1, I = 1) state MP2/6-311G(d,p) A/MHz 2849.35719(31)2850.30605(36) 2807.5641 B/MHz 1447.94807(22)1447.93251(34) 1455.4888 C/MHz 1424.36088(22)1424.37664(30) 1429.2876 1.5  aa /MHz4.9192(23)4.9290(36) 0.25(  bb -  cc ) /MHz1.54038(83)1.5393(11) DJDJ /kHz4.1478(44)4.1791(71) D JK /kHz18.773(16)18.721(21) DKDK /kHz22.761(40)20.642(26) d1d1 /kHz-0.0090(41)-0.0211(67) d2d2 /kHz0.0312(19)0.0352(18) Number of lines164134 RMS/kHz3.84.7 The fit: 15 N 2 -C 5 H 5 N

9. A 1 (  = 0, I = 0) stateB 2 (  = 1, I = 1) state MP2 rigid dimerPyridine R /Å 3.47 3.46  // 10(1) 4.6  // 90.0 V2V2 /cm -1 64.66 tor /cm -1 22.52  aa /MHz 3.2795(15)3.2880(24) -4.908(3)  bb /MHz 1.4410(166)1.4946(44) 1.434(3)  cc /MHz -4.72051(166)-4.7226(44) 3.474(3) IaIa /amu Å 2 177.49055(31)177.30693(36) 180.0062283.6824(6) IbIb /amu Å 2 349.03116(22)349.03492(34) 347.2228787.0606(6) IcIc /amu Å 2 354.81106(22)354.80714(30) 353.58804170.7816(6) N 2 -OCS V 2 = 40 cm -1 J. P. Connelly, S. P. Duxon, S. K. Kennedy, B. J. Howard, and J. S. Muenter, J. Mol. Spectrosc. 175, 85-98 (1996). Structural information: 15 N 2 -C 5 H 5 N

10. The structure 15 nitrogen-pyridine dimer. MP2/6-311G(d,p) binding energy: 438 cm -1 (1.3 kcal/mol) DimerR/Å C 5 H 5 N-N 2 3.47 a C 6 H 6 -N 2 3.50 b C 6 H 4 F 2 -N 2 3.48 c (N 2 ) 2 3.50 a Y. Ohshima, H. Kohguchi, and Y. Endo, Chem. Letts. 184, 21 (1991). b Schäfer, C. Kang, and D. W. Pratt, J. Phys. Chem. A 107, 10753-10758 (2003). C A. Wada and H. Kanamori, J. Chem. Phys. 109, 9434 (1998). [MP4 theory] N-N-N interaction

11. MW EXPERIMENTAL RESULTS CH 4 - C 5 H 5 N A floppy vdW system

12. Theory shows vdW bond distance can vary depending on the calculation methods. a K. Shibasaki, A. Fujii, N. Mikami, and S. Tsuzuki, J. Phys. Chem. A 110, 4397 (2006).

13. The spectrum of CH 4 -C 5 H 5 N. Sample: 0.5% pyridine + 2.5% CH 4 + 3 atm. Ne

14. ConstantUnit 12 CH 4 -C 5 H 5 N A-state (j CH4 = 0, I CH4 = 2) 12 CH 4 -C 5 H 5 N F-state (j CH4 = 1, I CH4 = 1) 13 CH 4 -C 5 H 5 N AMHz3006.3471(24)3007.0366(69)3002.090(13) BMHz1873.8308(44)1885.2402(83)1820.3973(33) CMHz1829.4969(62)1843.667(10)1782.8535(33) DJDJ kHz109.67(10)224.17(14)177.32(19) D JK kHz32.9(36)-144.2(30)-772.1(32) DKDK kHz373.6(470)101.2(40)437.1(21) d1d1 kHz-86.21(17)86.21 d2d2 kHz--42.32(79)-42.32 RMSkHz2.04.34.2  aa MHz2.99(16)  bb MHz3.92(31)  cc MHz0.93(31) M aa MHz0.036(29) RMSkHz88.0 b-dipole transitions

15. The structure of methane-pyridine: A vdW complex MP2/6-311++G(d,p) binding energy: 361 cm -1 (1.03 kcal/mol) a M. Schauer and E. R. Bernstein, J. Chem.Phys. 82, 726 (1985). b D. A. Roham, S. Suzuki, R. D. Suenram, F. J. Lovas S. Dasgupta, W. A. Goddard III, and B. A. Blake, Nature, 362, 735 (1993). DimerR/Å C 5 H 5 N-CH 4 3.77 a C 6 H 6 -CH 4 3.4-3.5 b C 6 H 6 -NH 3 3.59 A non-conventional NH    hydrogen bond complex

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