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-temperature¹H n.m.r. spectra of a series of dicarbonyl(triphenylphosphine)(1,3-di-t-butyl-2-methoxyarene)chromium compounds exihibit dynamic behaviour which is interpreted in terms of kinetic restrictiln 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 anX-ray crystal structure of dicarbonyl (triohenylphosphine)(1,3-di-t-butyl-2 methoxybenzene) chromium in which the O–CH₃group is syn to the chromium.