Hexaniobate anions connected by [Ni(cyclam)](2+) complexes yield two interpenetrating three- dimensional networks

摘要

Syntheses were performed at room temperature using Ni(NO3)(2)center dot 6H(2)O, cyclam (cyclam = 1,4, 8,11-tetraazacyclotetradecane) and the precursors Li-8[Nb6O19]center dot approximate to 22H(2)O or Na-7[HNb6O19]center dot 15H(2)O in a DMSO-H2O mixture. Yellow crystals of the new compound {[Ni(cyclam)](2)H4Nb6O19}center dot 12H(2)O could be obtained after one week applying the Li+ or Na+ salt as starting materials. The crystal structure is unique in polyoxoniobate (PONb) chemistry and displays two interpenetrating three-dimensional (3D) networks. The [Nb6O19](8-) anion is expanded by four Ni2+ centered complexes via Ni-O bonds to terminal O2- anions of the hexaniobate anion. The 3D networks are generated by further Ni-0 bond formation between neighboring [Nb6O19](8-) anions. The remaining void space is occupied by H2O molecules which form a water cluster.