Crystal structure of the photoaddition product of iodoform and 3,4,5-trimethylphenol

Abstract

A light yellow photoaddition compound is formed when dichloromethane solutions of iodoform and 3,4,5-trimethylphenol are irradiated with unfiltered light from a mercury vapour lamp. Three-dimensional X-ray diffraction analysis of crystals of this compound has shown them to be 4-di-iodomethyl-3,4,5-trimethylcyclohexa-2,5-dienone, indicating that the photoaddition has proceeded wholly by attack by photolytically generated ·CHl₂ radicals.

The structure was solved by direct methods and refined by full-matrix least-squares to R 0·047 for 1437 diffractometer measured intensities. Crystals are orthorhombic, space group Pbca, with Z= 8 in a cell of dimensions: a= 17·023 ± 0·009, b= 10·559 ± 0·004, and c= 12·889 ± 0·019 Å. Bond distances and angles are all reasonable.