The preparation of new oxoniobium(V) complexes from hydrated Niobium(V) Oxide: the crystal and molecular structure of Oxotris(2-pyridinolato-N-oxide)niobium(V)

摘要

Three oxoniobium(V) complexes ONbL3 with HL = tropolone (1), 2-pyridinol-N-oxide (2) or, 3-hydroxy-1,2-dimethyl-4(1H)-pyridone (3) are obtained in good yield by one step reactions from commercially available hydrated niobium(V) oxide in aqueous media. The products are characterized by elemental analysis, FT-IR spectroscopy, NMR spectroscopy (1H- and 13C-) and thermogravimetry. The crystal structure of oxotris(2-pyridinolato-N-oxide)niobium(V) is determined by single crystal X-ray diffraction, showing discrete molecules with pentagonal bipyramidal coordinated niobium. The 1H-NMR spectra of CDCl3 solutions indicate a fluxional behaviour for the three complexes.