Hydrothermal syntheses and crystal structures of two transition metal complexes supported by vanadate {V4O12}: {[ M (dpa)2]2V4O12} ( M = Co, Ni. dpa = 2,2′-dipyridylamine)

Hydrothermal reactions have been exploited in the syntheses of two new metavanadates, {[Co(dpa)2]2V4O12} · H2O (1) and {[Ni(dpa)2]2V4O12} · H2O (2), which were characterized by X-ray diffraction, IR and thermogravimetric analysis. Crystal data: C40H38N12O13Co2V4 (1) monoclinic. P2(1), a = 10.126(2), b = 17.639(4), c = 12.930(3) A, α = 90°, β = 98.356(4)°, γ = 90°, Z = 2; C40H38N12O13Ni2V4 (2) monoclinic. P2(1), a = 10.1037(9), b = 17.6680(14), c = 12.8832(10) A, α = 90°, β = 98.423(2)°, γ = 90°, Z = 2. The two complexes are isomorphic and their structures consist of a [V4O12]4− cluster bound to two [M(dpa)2]2+ moieties through the terminal oxygen atoms in a trans-conformation; the [V4O12]4− cluster adopts a chair-like configuration.