Photochromism in organomercury(II) dithizonates

Abstract

1 : 1 Complexes of organomercury(II) cations HgR+(R = Me, Ph, 2,6-dimethylphenyl, or 2,4,6-trimethylphenyl) and dithizone (and its p- and o-tolyl homologues) undergo reversible photoisomerization (yellow⇌blue) at conveniently measurable rates when dissolved in organic solvents. Structures for the isomers are deduced from visible, i.r., and 1H n.m.r. spectroscopy, measurements on the labile blue photoisomer being made on irradiated solutions.