Dynamic Model of Solution Reactions: Thermal Z/E Isomerization of Azobenzenes and Benzylideneanilines

Abstract

Pressure and viscosity effects on the rate of thermal Z/E isomerization of 4-(N,N-dimethylamino)-4'-nitroazobenzene and 4-(N,N-diethylamino)benzylidene-4'-trifluromethylaniline were studied in highly viscous solvents and compared with those of the corresponding 4-(N,N-dimethylamino) derivatives. In lower pressure region, similar pressure effects are obserbed. At highr pressures, on the other hand, retardation of the reaction of 4-(N,N-diethylamino) derivatives is stronger than that of 4-(N,N-dimethylamino) derivatives. These results indicates that microscopic friction felt by substrate is larger in a sterically bulkier 4-(N,N-diethylamino) derivatives. The analysis of the dynamic solvent effects on the basis of two-dimensional reaction coordinate model will be discussed.