X-Ray Crystal Structure of meso 1, 3 ; 1', 3'-Tetramethylleucoisoindigo and Nuclear Magnetic Resonance Studies on Leucoisoindigos

Abstract

The crystal structure of meso 1, 3 ; 1', 3'-tetramethylleucoisoindigo was determined by X-ray analysis. A comparative proton nuclear magnetic resonance study on the meso and racemic isomers of leucoisoindigos showed a characteristic high field shift of one set of aromatic protons, H (5)'s, in the meso isomers.