The effect of solvent on the electronic absorption spectra of the mesoionic compounds 2,3-diphenyl-2H-tetrazolium-5-thiolate and 4-phenyl-1,3,4-thiadiazolium-2-thiolate

Abstract

The electronic absorption spectra of two mesoionic compounds, 2,3-diphenyl-2H-tetrazolium-5-thiolate (I) and 4-phenyl-1,3,4-thiadiazolium-2-thiolate (II) have been measured in a number of pure solvents and in mixtures of water with acetone or pyridine. The hypsochromic shifts are found to be linearly related to the polarity parameter Z and Y of the solvents.