A highly selective hydrogen‐deuterium exchange in indolium heptamethine cyanines

Abstract

Chemical shift assignments in 1H nmr spectra of four tricarbocyanines have been made. Studies by 1H nmr have shown a rapid acid‐catalyzed proton exchange at positions 1′,7′ and a much slower exchange at positions 3′,5′ of the heptamethine chain. Base catalysis results in a slow exchange at positions 1′,7′ only. Copyright © 1993 Journal of Heterocyclic Chemistry