Coordination of niobium and tantalum oxides by Ar, Xe and O2:: Matrix isolation infrared spectroscopic and theoretical study of NbO2(Ng)2 (Ng = Ar, Xe) and MO4W (M = Nb, Ta; X = Ar, Xe, O2) in solid argon

The combination of matrix isolation infrared spectroscopic and quantum chemical calculation results indicate that the NbO2 molecule is coordinated by two noble gas atoms in forming the NbO2(Ng)(2) (Ng = Ar, Xe) complexes in solid noble gas matrixes. in contrast, the TaO2 molecule is not able to form similar noble gas complex. The niobiurn and tantalum dioxides further react with dioxygen to form the side-on bonded s uperoxo-d i oxide complexes MO4 (M = Nb, Ta), which are coordinated by one argon atom in solid argon matrix. The coordinated Ar atom in MO4(Ar) can be replaced by O-2 or Xe in forming the MO6 and MO4(Xe) complexes. The results indicate that the NbO2, NbO4 and TaO4 molecules trapped in solid noble gas matrixes should be regarded as the NbO2(Ng)(2) and MO4(Ng) (Ng = Ar, Xe; M = Nb, Ta) complexes instead of "isolated" metal oxide species. (c) 2008 Elsevier B.V. All rights reserved.