Assembly of niobium-phosphate cluster and in situ transition-metal-containing derivativesElectronic supplementary information (ESI) available: X-ray crystallographic data, figures: solid-state FT-IR, XRD, TGA, 31P MAS NMR, and BVS calculation results. CCDC 1540342-1540347. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7ce00603a

A novel phosphorus incorporated peroxopolyoxoniobate (CN 3 H 6 ) 6 H 4 [P 4 Nb 6 (O 2 ) 6 O 24 ]·4H 2 O ( 1 ) has been successfully synthesized and characterized. Compound 1 possesses a cluster of [P 4 Nb 6 (O 2 ) 6 O 24 ] 10− and can be viewed as the fusion of two {P 2 Nb 3 (O 2 ) 3 O 14 } subunits by corner-sharing of bridging oxygen atoms. Furthermore, by reacting transition metals with the polyanion [P 4 Nb 6 (O 2 ) 6 O 24 ] 10− formed in situ , we have discovered a series of transition-metal-containing niobium phosphate cluster derivatives, (CN 3 H 6 ) 4 H 4 [{Cd(H 2 O) 4 }{P 4 Nb 6 (O 2 ) 6 O 24 }]·7H 2 O ( 2 ), Cs 3 H 3 {[M(H 2 O) 4.5 ] 2 [P 4 Nb 6 (O 2 ) 6 O 24 ]}·5H 2 O [M = Co ( 3 ), Ni ( 4 ), Zn ( 5 )] and Cs 3 H 3 [{Cd(H 2 O) 4 } 2 {P 4 Nb 6 (O 2 ) 6 O 24 }]·12H 2 O ( 6 ). Compounds 2-6 are based on the {P 4 Nb 6 (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 Cd 2+ . A new peroxoniobophosphate and its novel transition metal derivatives have been synthesized, representing the first examples of transition-metal-containing peroxoniobophosphates.