Copper pyrazole directed crystallization of decavanadates: synthesis and characterization of {Cu(pz)}4[{Cu(pz)3}2V10O28] and (Hpz)2[{Cu(pz)4}2V10O28]·2H2O

Abstract

Crystal engineering of two new fully oxidized decavanadate based 1-D solid {Cu(pz)₄}[{Cu(pz)₃}₂V₁₀O₂₈], 1 and a 2-D inorganic–organic hybrid solid (Hpz)₂[{Cu(pz)₄}₂V₁₀O₂₈]·2H₂O, 2 have been effected under self-assembly condition. 1 contains 1-D anionic chains of the composition [{Cu(pz)₃}₂V₁₀O₂₈] intercalated with {Cu(pz)₄}²⁺ as counter cations. 2 contains 2-D anionic sheets of the composition [{Cu(pz)₄}₂V₁₀O₂₈] 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) Å, b = 11.976(1) Å, c = 12.900(1) Å, α = 100.226(2)°, β = 105.549(3)°, γ = 118.571(2)°, Z = 1; 2, triclinic, space group P-1, a = 11.582(2) Å, b = 11.659(1) Å, c = 12.451(1) Å, α = 114.660(3)°, β = 107.439(2)°, γ = 91.639(3)°, Z = 2.