Time-resolved IR studies of gas-phase photochemistry of Co(CO)3NO

Abstract

Time-resolved IR spectroscopy has been used to study the gas-phase photochemistry of Co(CO)₃NO at 355 and 266 nm. The major IR spectra observed have been assigned. 355 nm photolysis of Co(CO)₃NO leads to the predominant formation of Co(CO)₃ and Co(CO)₂No via elimination of NO and CO, respectively. The branching ratio for loss of NO vs. loss of CO was ca. 3/2, favouring scission of the Co—NO bond. 266 nm photolysis resulted in the formation of Co(CO)₂ and NO-retaining products. The overall branching ratio for NO-depleted vs. NO-retaining products was ca. 2. The implication behind these branching ratios is discussed with regard to the photodissociation mechanism. Co(CO)_n reacts with CO forming Co(CO)_n+1 with rate constants of (3.4 ± 0.5)× 10^–11 and (3.5 ± 0.6)× 10^–11 cm³ molecule^–1 s^–1, for n= 3 and 2, respectively.