Matrix Infrared Spectroscopic and Theoretical Investigations of Uranium Atom and Methanol Reaction Products

Abstract

Reactions of laser-ablated uranium atoms and methanol are investigated in solid argon using matrix isolation and infrared spectroscopy. Four new product molecules are identified with the help of isotopically substituted methanol as well as density functional frequency calculations. Uranium atoms react spontaneously with methanol on annealing to form the U(II) insertion product CH(3)OUH, which has a quintet ground state with strong C-O and U-H stretching vibrations. Further sample annealing allows the reaction of CH(3)OUH and another methanol molecule to eliminate H(2) and give the U(OCH(3))(2) product. Near-UV-vis irradiation isomerizes the CH(3)OUH molecule to the 32 kcal/mol lower energy U(IV) CH(3)U(O)H isomer and the U(OCH(3))(2) molecule to the 28 kcal/mol lower energy CH(3)OU(O)CH(3) isomer. Both U(IV) products have triplet ground states, U═O double bonds, and pyramidal skeletal structures.