Microcalorimetric studies. Thermal decomposition and iodination of bis(benzene)chromium, bis(benzene)-chromium iodide, and some (arene)chromium tricarbonyls

Abstract

Thermal decomposition studies, and measurements of the heats of reaction with iodine vapour of bis(benzene)chromium, bis(benzene)chromium iodide, and some (arene)chromium tricarbonyls were made by high temperature microcalorimetry. The following standard enthalpies of formation, ΔH^° _f(cryst.)/kcal mol^–1, were obtained: [graphic omitted] Available or estimated enthalpies of sublimation were combined with these data to obtain the total enthalpies of disruption of the Cr-ligand bonds in these molecules. In the (arene)chromium tricarbonyls, (A)Cr(CO)₃, the ligand binding energy is substantially increased on replacing A = benzene by hexamethylbenzene.