‘Chromyl carbonyl’. Synthesis of [CrO2(CO)2] in low-temperature matrices

Abstract

Photolysis of [Cr(CO)₆] in O₂-doped Ar matrices at low temperatures produces, inter alia, a species which contains both CO and O₂. Experiments with ¹³CO-enriched [Cr(CO)₆] and with matrices doped with ¹⁶O₂, ¹⁶O¹⁸O, and ¹⁸O₂ show that this species contains two CO groups and two oxygen atoms double-bonded to the metal. This structure is thus ‘chromyl carbonyl’ and further evidence for this comes from the photochemical generation of the species from chromyl chloride in solid CO. The generation of CO and CO₂ during the carbonyl photolysis suggests a possible mechanism involving oxidation of CO to CO₂ on the metal centre.