An infrared spectroscopic and density functional investigation of dinitrogen activation by group IV metal atoms

Reactions of laser-ablated Ti, Zr, and Hf atoms with N-2 in excess argon an d excess dinitrogen have produced the MN and (N-2)(x)MN molecules in additi on to M(mu-N)(2)M with no dinitrogen bond. Evidence is presented for simple eta(1)-N-2 and higher complexes for each metal. The observation of cyclic Ti(N-2) and Zr(N-2) molecules with N-N stretching frequencies at 1125.9 and 1022.8 cm(-1), respectively, indicate significant activation of the dinitr ogen bond. The identification of product molecules is based on isotopic sub stitution and the results of density functional theory frequency calculatio ns. (C) 1999 American Institute of Physics. [S0021-9606(99)00518-8].