Hydrogen bonding in the gas phase. Part 4.—Infrared spectroscopic investigation of O—H ⋯ O and C—H ⋯ N complexes : alcohol + ether and trichloromethane + amine systems

Hussein, Mohammed Ali; Millen, D. J.

doi:10.1039/f29767200693

Cited by 22 publications

(13 citation statements)

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“…which corresponds to a redshift of approximately 75 cm À1 for the corresponding CÀH bond. [32] Excluding this case, typical CÀH redshifts observed in 1:1 complexes in gas-phase measurements are less than 50 cm À1 . In comparison, a redshift of 82 cm À1 in the 7-AI:CHCl 3 complex stands out.…”

Section: Discussionmentioning

confidence: 94%

“…CHCl 3 :(NH 3 ) 3 À102 [14] supersonic jet FTIR jet temp. CHF 3 :NH 3 + 7.6 [30] liquid Xe 188 K CHF 3 :NH 3 À21 [29] Ar matrix 20 K CHF 3 :NH 3 À45 [29] N 2 matrix 20 K CHCl 3 :NMe 3 À105 [31] liquid Kr 120 K F 2 ClCH:NMe 3 À32 [31] liquid Kr 120 K CHF 3 :NMe 3 À22.8 [30] liquid Ar 90 K CDCl 3 :NH 3 À12 [32] gas-phase IR room temp. CDCl 3 :MeNH 2 À26 [32] gas-phase IR room temp.…”

Section: Discussionmentioning

confidence: 99%

“…CDCl 3 :MeNH 2 À26 [32] gas-phase IR room temp. CDCl 3 :Me 2 NH À45 [32] gas-phase IR room temp. CDCl 3 : NMe 3 À53 [32] gas-phase IR room temp.…”

Section: Discussionmentioning

confidence: 99%

“…CDCl 3 :Me 2 NH À45 [32] gas-phase IR room temp. CDCl 3 : NMe 3 À53 [32] gas-phase IR room temp. CHF 3 :Pyridine + 3 [30] liquid Xe 188 K CHCl 3 :7-AI À82 present work IR-UV jet jet temp.…”

Section: Discussionmentioning

confidence: 99%

“…[32] Excluding this case, typical CÀH redshifts observed in 1:1 complexes in gas-phase measurements are less than 50 cm À1 . [32] Excluding this case, typical CÀH redshifts observed in 1:1 complexes in gas-phase measurements are less than 50 cm À1 .…”

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confidence: 94%

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CH⋅⋅⋅N Hydrogen‐Bonding Interaction in 7‐Azaindole:CHX₃ (X=F, Cl) Complexes

et al. 2013

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The C-H···Y (Y=hydrogen-bond acceptor) interactions are somewhat unconventional in the context of hydrogen-bonding interactions. Typical C-H stretching frequency shifts in the hydrogen-bond donor C-H group are not only small, that is, of the order of a few tens of cm(-1) , but also bidirectional, that is, they can be red or blue shifted depending on the hydrogen-bond acceptor. In this work we examine the C-H···N interaction in complexes of 7-azaindole with CHCl3 and CHF3 that are prepared in the gas phase through supersonic jet expansion using the fluorescence depletion by infra-red (FDIR) method. Although the hydrogen-bond acceptor, 7-azaindole, has multiple sites of interaction, it is found that the C-H···N hydrogen-bonding interaction prevails over the others. The electronic excitation spectra suggest that both complexes are more stabilized in the S1 state than in the S0 state. The C-H stretching frequency is found to be red shifted by 82 cm(-1) in the CHCl3 complex, which is the largest redshift reported so far in gas-phase investigations of 1:1 haloform complexes with various substrates. In the CHF3 complex the observed C-H frequency is blue shifted by 4 cm(-1). This is at variance with the frequency shifts that are predicted using several computational methods; these predict at best a redshift of 8.5 cm(-1). This discrepancy is analogous to that reported for the pyridine-CHF3 complex [W. A. Herrebout, S. M. Melikova, S. N. Delanoye, K. S. Rutkowski, D. N. Shchepkin, B. J. van der Veken, J. Phys. Chem. A- 2005, 109, 3038], in which the blueshift is termed a pseudo blueshift and is shown to be due to the shifting of levels caused by Fermi resonance between the overtones of the C-H bending and stretching modes. The dissociation energies, (D0), of the CHCl3 and CHF3 complexes are computed (MP2/aug-cc-pVDZ level) as 6.46 and 5.06 kcal mol(-1), respectively.

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Section: Discussionmentioning

confidence: 94%