The dynamic stereochemistry of some dicarbonyl[phosphorus(III)](I,3-di-t- butyl-2-methoxyarene)chromium compounds. Evidence for restricted rotation about arene-substituent bonds, including an x-ray crystal structure of dicarbonyl(triphenylphosphine)(1,3-di-t-butyl-2-methoxybenzene)chromium

Abstract

Low-temperature 1H n.m.r. spectra of a series of dicarbonyl(triphenylphosphine)(1,3-di-t-butyl-2-methoxyarene)chromium compounds exhibit dynamic behaviour which is interpreted in terms of kinetic restriction of rotation about the arene-methoxy bond, and similar behaviour is observed in a chelated aryl chromium analogue of these compounds; this explanation is supported by an X-ray crystal structure of dicarbonyl-(triphenylphosphine)(1,3- di-t-butyl-2-methoxybenzene)chromium in which the D-CH3 group is syn to the chromium.