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.