Formation of Metal Oxyfluorides from Specific Metal Reactions with Oxygen Difluoride: Infrared Spectroscopic and Theoretical Investigations of the OScF 2 Radical and OScF with Terminal Single and Triple ScO Bonds

The scandium oxydifluoride free radical, OScF 2 , is produced by the spontaneous, specific reaction of laser ablated Sc atoms with OF 2 in solid argon and characterized by using matrix infrared spectroscopy and theoretical calculations. The OScF 2 molecule is predicted to have C 2 v symmetry and a 2 B 2 ground state with an unpaired electron located primarily on the terminal oxygen atom, which makes it a scandium difluoride molecule coordinated by a neutral oxygen atom radical in forming the ScO single bond. The closed shell singlet OScF molecule with an obtuse bent geometry has a much shorter ScO bond of 1.682 Å than that of the OScF 2 radical (1.938 Å) on the basis of B3LYP calculations. The ScO bond in OScF consists of two covalent bonds and a dative bond in which the oxygen 2p π lone pair donates electron density into an empty Sc 3d orbital thus forming a triple oxo bond. Density functional calculations suggest it is highly exothermic for fluorine transfer from OF 2 to scandium, which favors the formation of the OScF 2 radical species as well as the OScF molecule after fluorine loss.