Torsional isomerism of allyl chloride, bromide and iodide
Abstract
The infra-red spectra of allyl (propene-3) chloride, bromide and iodide vapour and liquid have been examined from 60 to 2000 cm–1, and crystal from 60 to 450 cm–1. Raman polarizabilities have been measured for liquid allyl chloride and bromide. The predominating torsional isomer is a twisted-trans form, the proportion of the minor cis form decreasing from chloride to iodide. The structures observed support the view that spin correlation plays an important role in torsion barriers.