Supersonic beam investigations of indole and indole–halomethane complexes: intermolecular interactions

Abstract

. Can. J. Chem. 63, 1502Chem. 63, (1985. We report the findings of a supersonic beam investigation of the I : 1 gas phase complexes of indole with various halomethanes. The unique environment of the supersonic jet provides a method by which the pairwise intermolecular interactions of these complexes can be studied without the complications of condensed media effects. The behavior of argon and methane van der Waals molecules is described first in order to.provide examples of simple dispersive interactions. These are then contrasted with complexing species such as CF, and CCI, where repulsive interactions offset the stabilization due to dispersive and dipole -induced dipole forces. Finally, we show that the interaction between the probe molecule and CHC13 and CH2CI2 is apparently hydrogen bonding with the indole .rr electronic system. The implications of these intermolecular interactions on the area of general anesthesia are discussed in terms of a picture in which both the hydrophobic and polar portions of cell membrane may be reversibly affected. [Traduit par le journal]

Sulfur, Not Too Far Behind O, N, and C: SH···π Hydrogen Bond

“…The excited-state lifetimes for the IND, IND·H 2 O, and IND·H 2 S complexes were 19.7, 22.8, and 11.6 ns, respectively. The values for the IND and IND·H 2 O complexes were within 10% of the reported values. ,− There was hardly any change in the S 1 state lifetime for the IND·H 2 O complex, whereas in the case of the IND·H 2 S complex, it shortened considerably. For 3-MI, the S 1 state lifetime was found to be 21 ns, while those for 3-MI·H 2 O and 3-MI·H 2 S were 14.8 and 7.9 ns, respectively.…”

“…The lifetime measurements for both the monomers and their complexes were carried out for the band origin excitation and fluorescence decay curves are provided in Figure 7. The lifetimes of the excited state were obtained by fitting the experimental data with a single exponential after [90][91][92][93][94] There was hardly any change in the S 1 state lifetime for the IND • H 2 O complex, whereas in the case of the IND • H 2 S complex, it shortened considerably. For 3-MI, the S 1 state lifetime was found to be 21 ns, while those for 3-MI • H 2 O and 3-MI • H 2 S were 14.8 and 7.9 ns, respectively.…”

Spectroscopy of solvent complexes with indoles: induction of 1La-1Lb state coupling

“…23 We have carried out a dual tracked LIF scan over the first four features (Figure 14) and observe a relative peak reduction of the complex features in the lower scan. DCM is not expected to act as a proton acceptor and therefore should not bind at the N site.…”

“…An excitation spectrum has already been reported by Hager and Wallace.23 A series of progression features with ~20-cm~1 spacing is evident to the blue of the bare molecule origin, beginning either slightly to the blue or red of the bare molecule origin and extending at least 160 cm"1 to the blue. 23 We have carried out a dual tracked LIF scan over the first four features (Figure 14) and observe a relative peak reduction of the complex features in the lower scan. The lifetimes (Table I) are close to those obtained for 'La emitting features induced in indole by formamide, acetamide, and water.…”

Experimentally measured permanent dipoles induced by hydrogen bonding. The Stark spectrum of indole–NH3

“…Numerous spectroscopic investigations of both polar and non-polar indole clusters afford a wealth of information on hydrogen bonding, van der Waals bonding, and solvation-controlled 1 L a -1 L b state coupling in indole and its derivatives. [1][2][3][4][5][6][7][8][9][10] At significantly higher resolution, molecular beam measurements of indole and some select indole complexes have determined the lowest excited (S 1 ) state to be of 1 L b symmetry. [11][12][13][14][15][16][17] Recently, 1 L a -1 L b coupling in the bare molecule has been thoroughly explored using rotationally resolved data and a high level theoretical analysis.…”