Journal of Physical Chemistry A, Vol.121, No.40, 7603-7612, 2017
Infrared Spectroscopic and Theoretical Studies on the OMF2 and OMF (M = Cr, Mo, W) Molecules in Solid Argon
Group 6 metal oxide fluoride molecules in the form of OMF2 and OMF (M = Cr, Mo, W) were prepared via the reactions of laser-ablated metal atoms and OF2 in excess argon. Product identifications were performed by using infrared spectroscopy, (OF2)-O-18 samples, and electronic structure calculations. Reactions of group 6 metal atoms and OF2 resulted in the formation of ternary OCrF2, OMoF2, and OWF2 molecules with C-2v symmetry in which the tetravalent metal center is coordinated by one oxygen and two fluorine atoms. Both OCrF, and OMoF2 are computed to possess triplet ground states, and a closed shell singlet is the ground state for OWF2. Triatomic OCrF, OMoF, and OWF molecules were also observed during sample deposition. All three molecules were computed to have a bent geometry and quartet ground state. A bonding analysis showed that the OMF2 molecules have highly ionic M-F bonds. (OCrF2)-O-3 and (OMoF2)-O-3 have an M-O double bond composed of a sigma bond and a pi bond. (OWF2)-O-1 has an M-O triple bond consisting of a a bond, a pi bond, and a highly delocalized 0 lone pair forming the other pi bond. The M-O bonds in the OMF compounds have triple-bond character for all three metals.