Metal carbonyl photochemistry. Part 1. Photolysis of the Group 6 hexacarbonyls in hydrocarbon glasses; the species M(CO)5, M(CO)4, M(CO)3, and [M(CO)5(OH2)]

Abstract

Photolysis of the Group 6 metal hexacarbonyls in hydrocarbon glasses at 80 K gives rise to species M(CO)_n(n= 3–5), presumably weakly solvated, by successive CO loss. Primary and subsequent processes both show photo-reversal. Slow warming leads to recombination, hexacarbonyl precipitation, poorly defined, possibly polymeric species, and formation of species [M(CO)₅(OH₂)]. Visible-u.v. and i.r. spectra are presented. Solute–cosolute interactions are shown to exist in H₂-doped glasses. The species [Cr(CO)₅(OH₂)] is photolabile in solution but not in the glass; the implications of this are discussed.