Photooxidation of Matrix-Isolated Nickel Tetracarbonyl in the Presence of Dioxygen

Article abstract of DOI:10.1021/ic00128a034

UV Photolysis (λ = ca. 254 nm) of Ni(CO)4 molecules isolated in O2-doped argon matrices at ca. 20 K has been monitored by reference to the IR spectra of the matrices. These spectra indicate that Ni(CO)4 undergoes photooxidation to give four distinct nickel carbonyl intermediates A-D with the release of CO and CO2, ultimately to arrive at the final product (η2-O2)2Ni. The stoichiometry and likely structure of each intermediate A-D have been deduced by analysis of the number, energies, andrelative intensities of its IR absorptions, with particular reference to the response to (13)CO- and (18)O-enrichment. Hence, the following identities have been inferred: A, Ni(CO)3; B, (η2-O2)Ni(CO)2; C, (O2)Ni(CO)3; and D, O=Ni(CO)2. The system exhibits some photoselectivity, and reversal of the reactions leading to A-D can be effected under the action of UV radiation with wavelengths near 313 nm or by annealing the deposit to ca. 30-35 K. A partial mechanism is proposed to account for the course of the matrix reactions.