Conformations of meso and Racemic 1, 1', 3, 3'-Tetramethylleucoisoindigos in Solid State and Solution

Abstract

1, 3-Dimethyl-2-indolinone gave meso and racemic dimers by the oxidative dimerization reaction. Conformations of these dimers were examined in solid and solution, respectively. The meso isomer kept the ±sc conformation both in solid and solution. But the racemic isomer showed the -sc conformation in solution, which was confirmed by the nuclear Overhauser effect experiments in the ¹H-NMR. We also showed that the -sc conformation in solution was different from that in solid. We measured the +sc conformation in solid by X-ray analysis.