Photochromism of spiropyrans in organized molecular assemblies. Formation of J- and H-aggregates of photomerocyanines in bilayers–clay matrices

Abstract

Photochromism of a series of 1′-alkyl-3′,3′-dimethyl-6-nitro-8-alkanoyloxymethylspiro(2H-1-benzopyran-2,2′-indoline) derivatives (SPs) having different lengths of their alkyl chains has been investigated in didodecyldimethylammonium chloride–clay matrices; stable H (parallel type) and J (head-to-tail type) aggregates of photo-merocyanines are formed when SPs containing an appropriate length of alkyl chains are irradiated.