Titanium oxide complexes with dinitrogen. Formation and characterization of the side-on and end-on bonded titanium oxide-dinitrogen complexes in solid neon

摘要

The reactions of titanium oxide molecules with dinitrogen have been studied by matrix isolation infrared spectroscopy. The titanium monoxide molecule reacts with dinitrogen to form the TiO(N-2)_x (x = 1-4) complexes spontaneously on annealing in solid neon. The TiO(η~1- NN) complex is end-on bonded and was predicted to have a ~3A″ ground state arising from the ~3δ ground state of TiO. Argon doping experiments indicate that TiO(η~1-NN) is able to form complexes with one or more argon atoms. Argon atom coordination induces a large red-shift of the N-N stretching frequency. The TiO(η~2-N _2)_2 complex was characterized to have C_(2v) symmetry, in which both the N_2 ligands are side-on bonded to the titanium metal center. The tridinitrogen complex TiO(η~1-NN) _3 most likely has C_(3v) symmetry with three end-on bonded N_2 ligands. The TiO(η~1-NN)_4 complex was determined to have a C_(4v) structure with four equivalent end-on bonded N_2 ligands. In addition, evidence is also presented for the formation of the TiO_2(η~1-NN)_x (x = 1-4) complexes, which were predicted to be end-on bonded.