Coordination of niobium and tantalum oxides by Ar, Xe and O 2: Matrix isolation infrared spectroscopic and theoretical study of NbO 2(Ng) 2 (Ng = Ar, Xe) and MO 4(X) (M = Nb, Ta; X = Ar, Xe, O 2) in solid argon

Abstract

The combination of matrix isolation infrared spectroscopic and quantum chemical calculation results indicate that the NbO 2 molecule is coordinated by two noble gas atoms in forming the NbO 2(Ng) 2 (Ng = Ar, Xe) complexes in solid noble gas matrixes. In contrast, the TaO 2 molecule is not able to form similar noble gas complex. The niobium and tantalum dioxides further react with dioxygen to form the side-on bonded superoxo-dioxide complexes MO 4 (M = Nb, Ta), which are coordinated by one argon atom in solid argon matrix. The coordinated Ar atom in MO 4(Ar) can be replaced by O 2 or Xe in forming the MO 6 and MO 4(Xe) complexes. The results indicate that the NbO 2, NbO 4 and TaO 4 molecules trapped in solid noble gas matrixes should be regarded as the NbO 2(Ng) 2 and MO 4(Ng) (Ng = Ar, Xe; M = Nb, Ta) complexes instead of “isolated” metal oxide species.