Studies on the Conformational Equilibrium of trnas-2-Styrylquinoline

Abstract

The absorption and fluorescence specta of 2-styrylquinoline (2-StQ) indicate that two conformers exist in equilibrium in aprotic solvents, whereas only one conformer exists in protic solvents. The intermolecular hydrogen bonding between the solute and solvent plays an important role in changing the conformational equilibrium of 2-StQ. Comparing the conformationally restricted analogue 3-methyl-2-styrylquinoline with 2-StQ, the long wavelength absorbing component of 2-StQ can be assigned to the conformer (B) which has a planar geometry and the short wavelength absorbing species can be assigned to the conformer (A) which has the quinoline ring twisted from the molecular plane.