Diastereomeric isomerization of hetaryl leuco-TAM dyes, (2Z, 2 ' E)-2,2 '-(2-phenyl propane-1,3-diylidene)bis(1,3,3-trimethylindoline) derivatives in various organic solvents

Abstract

The diastereomeric isomerization of the ZE isomers of (2Z, 2'E)-2,2'-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives were examined by H-1 NMR spectroscopy in various organic solvents. In non-polar solvents, such as benzene, THF, and chloroform, the ZE isomers of these molecules equilibrated into a mixture of ZE/EE or ZE/EE/ZZ isomers with time, whereas the isomers were inert in polar organic solvents, such as acetone and DMSO. Theoretical calculations of the energies and dipole moments of the diastereomers in different media were performed using the Jaguar program. (C) 2010 Elsevier Ltd. All rights reserved.