Thermal and photoisomerisation of ion pairs of the 1,3-diphenyl-2-azallyl carbanion

Abstract

Upon irradiation with white light, the predominant conformation of the 1,3-diphenyl-2-aza-allyl carbanion is changed from trans,trans to cis,trans. The kinetics of the reverse dark reaction have been studied. The loose ion pairs with lithium, sodium, and potassium all have very similar Arrhenius parameters; the tight ion pairs with sodium and potassium, but not with lithium, have smaller values of both E and A. The electronic spectrum depends upon the conformation and, to some extent, upon the nature of the ion pairing.