PHOTOCHROMISM OF SPIROPYRANS IN ORGANIZED MOLECULAR ASSEMBLIES - FORMATION OF J-AGGREGATES AND H-AGGREGATES OF PHOTOMEROCYANINES IN BILAYERS CLAY MATRICES

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.