Crystal and molecular structures of dichloro(oxo)-2,2′-bipyridylethoxyniobium(V) and tetraphenylarsonium oxopentathiocyanatoniobate(V)

Abstract

The crystal structures of dichloro(oxo)-2,2′-bipyridylethoxyniobium(V) and tetraphenylarsonium oxopentathiocyanatoniobate(V) have been determined by three-dimensional X-ray structure analysis. Both complexes contain octahedrally co-ordinated niobium atoms with an oxygen atom multiply bonded to niobium. In the case of [NbOCl₂(OEt)(bipy)] the niobium atom is surrounded by two nitrogen atoms from the bipyridyl ligand at 2·32 and 2·35 Å, one oxygen atom from the ethoxy-group at 1·87 Å, an oxo-oxygen atom at 1·71 Å, and two chlorine atoms at 2·43 and 2·46 Å, respectively. In the anion of [Ph₄As]₂[NbO(NCS)₅] the equatorial apices of the octahedron are occupied by four nitrogen atoms from four thiocyanates at the mean distance of 2·09 Å, the fifth position is occupied by the oxo-oxygen at 1·70 Å, while the sixth position (trans to the oxo-oxygen) at 2·27 Å belongs to the nitrogen atom from the fifth thiocyanato-group.