Assembly of niobium-phosphate cluster and in situ transition-metal-containing derivatives

A novel phosphorus incorporated peroxopolyoxoniobate (CN3H6)(6)H-4[P4Nb6(O-2)(6)O-24]center dot 4H(2)O (1) has been successfully synthesized and characterized. Compound 1 possesses a cluster of [P4Nb6(O-2)(6)O-24](10-) and can be viewed as the fusion of two {P2Nb3(O-2)(3)O-14} subunits by corner-sharing of bridging oxygen atoms. Furthermore, by reacting transition metals with the polyanion [P4Nb6(O-2)(6)O-24](10-) formed in situ, we have discovered a series of transition-metal-containing niobium phosphate cluster derivatives, (CN3H6)(4)H-4[{Cd(H2O)(4)}{P4Nb6(O-2)(6)O-24}]center dot 7H(2)O (2), Cs3H3{[M(H2O)(4.5)]2[P4Nb6(O-2)(6)O-24]}center dot 5H(2)O [M = Co (3), Ni (4), Zn (5)] and Cs3H3({Cd(H2O)(4)}(2){P4Nb6(O-2)(6)O-24}]center dot 12H(2)O (6). Compounds 2-6 are based on the {P4Nb6(O-2)(6)O-24)(10-) cluster and 3, 4 and 5 show zero-dimensional constructions whereas 2 and 6 can form 1D chains attributed to the larger radius of Cd2+.