Excimer Laser Photolysis of Gas-Phase W(CO)6

Article abstract of DOI:10.1021/j100324a037

Laser-Based time-resolved infrared absorption spectroscopy was performed to investigate the excimer laser, XeF (351 nm), XeCl (308 nm), and KrF (248 nm), photolysis of W(CO)6 in the gas phase.The spectra observed in the wavenumber region between 1700 and 2033 cm^-1 show the primary production of coordinatively unsaturated tungsten carbonyls through a single photon mechanism.The extent of the fragmentation depends strongly on the absorbed photon energy.Infrared assignments for W(CO)4 and W(CO)5 are determined unambiguously from the stoichiometry revealed by the kinetics of the reactions with added CO.These assignments suggest that W(CO)5 is the only primary product in the XeF and XeCl laser photolysis while W(CO)4 is the main product from KrF laser photolysis.For W(CO)5 the C-O stretching bands are around 1942 and 1980 cm^-1, and those of W(CO)4 are at around 1909 and 1957 cm^-1.The infrared absorption spectra lead to low-symmetry structure assignments of C4_υ for W(CO)5 and C_2υ for W(CO)4.This is consistent with the assignment from low-temperature inert gas matrices.These coordinatively unsaturated tungsten carbonyls react with CO about once in every 10 collisions.