No abstract

No abstract

The ultraviolet and visible absorption spectra of indigo and of six halogen-substituted indigo dyes were determined in chloroform solution. In contrast with the behavior of thioindigo dyes, no evidence was found for photochemical isomerization. This was believed to be attributable to the preferential stabilization of the trans configuration by hydrogen-bonding.The discovery of phototropism in , '-diacetylmdigo and a comparison of the infrared absorption spectra of indigo and thioindigo provided evidence for this hypothesis. In addition, the effect of halogen substitution on the ultraviolet and visible spectra was considered.

No abstract

No abstract