Photophysical Properties and Photoisomerization of Aza-derivaties of trans-2-Styrylnaphthalenes: trans-1-(2-pyrazinyl)-2-(n-quinoxalinyl)ethylene

Abstract

Extensive vibronic mixing between the lowest excited 1(pi,pi*) (or 1(n,pi*)) and 1(n,pi*) (or 1(pi,pi*)) states leads to efficient non-radiative decay in the excited singlet state of trans-1-2-pyrazinyl)-2-(n-quinoxalinyl)ethylene (n-PyQxE; n = 2, 6) (aza derivatives of trans-2-styrylnaphthalene (2-StN)). Azulene quenching of direct and triplet-sensitized trans --> cis photoisomerization of n-PyQxE indicates that direct photoisomerization proceeds through the triplet manifold only at room temperature.