Copper pyrazole directed crystallization of decavanadates: synthesis and characterization of {Cu(pz)}(4)[{Cu(pz)(3)}(2)V10O28] and (Hpz)(2)[{Cu(pz)(4)}(2)V10O28]center dot 2H(2)O

Crystal engineering of two new fully oxidized decavanadate based 1-D solid {Cu(pz)(4)}[{Cu(pz)(3)}(2)V10O28], 1 and a 2-D inorganic-organic hybrid solid (Hpz)(2)[{Cu(pz)(4)}(2)V10O28]center dot 2H(2)O, 2 have been effected under self-assembly condition. 1 contains 1-D anionic chains of the composition [{Cu(pz)(3)}(2)V10O28] intercalated with {Cu(pz)(4)}(2+) as counter cations. 2 contains 2-D anionic sheets of the composition [{Cu(pz)(4)}(2)V10O28] incorporating pyrazolium counter cations and water molecules. Self-assembly of 1 and 2 is interpreted in terms of molecular recognition between reasonable soluble molecular species in the supramolecular reaction along the mechanistic approach proposed by Ramanan and Whittingham for rationalising metal-organic framework structures. Low temperature magnetic measurements of 1 and 2 show copper in divalent state with Curie behaviour. Crystal data: 1, triclinic, space group P-1, a = 11.671(1) angstrom, b = 11.976(1) angstrom, c = 12.900(1) angstrom, alpha = 100.226(2)degrees, beta = 105.549(3)degrees, gamma = 118.571(2)degrees, Z = 1; 2, triclinic, space group P-1, a = 11.582(2) angstrom, b = 11.659(1) angstrom, c 12.451(1) angstrom, alpha = 114.660(3)degrees, beta = 107.439(2)degrees, gamma = 91.639(3)degrees, Z = 2.