One-dimensional vanadium oxide chains containing covalently bound copper coordination complexes: Hydrothermal synthesis and characterization of Cu(H₂N(CH₂)₂NH₂)[V₂O ₆], Cu(C₁₀H₈N₂)[V₂O₆], and Cu(C₁₀H₈N₂)₂[V₂O ₆]

The hydrothermal reactions of CuCl₂ · 2H₂O, V₂O₅, and bidentate amines (2,2′-dipyridyl or ethylenediamine) gave the three new one-dimensional (1-D) vanadium oxide chain compounds, Cu(H₂N(CH₂)₂NH₂)[V₂O ₆], 1, Cu(C₁₀H₈N₂)[V₂O₆], 2, and Cu(C₁₀H₈N₂)₂[V₂O ₆], 3, which contain copper coordination complexes covalently bound to vanadium oxide chains. All were structurally characterized via single-crystal X-ray diffraction. Crystal data are as follows: 1, monoclinic, space group P2₁/n (No. 14) with a = 5.772(2) Å, b = 8.143(3) Å, c = 17.483(2) A, β = 90.43(2)°, Z = 4, p_calc = 2.599 g/cm₃, and R(R_w) = 0.029 (0.028); 2, triclinic, space group P1 (No. 2) with a = 10.114(2) Å, b = 10.839(3) Å, c = 5.810(3) Å, α = 94.75(3)°, β = 101.16(3)°, γ = 89.81(2)°, Z = 2, p_calc = 2.27 g/cm³, and R(R_W) = 0.035 (0.044); 3, monoclinic, space group P2₁/a (No. 14) with a = 10.478(2) Å, b = 13.779(2) Å, c = 14.513(3) Å, β = 100.39(1)°, Z = 4, and p_calc = 1.849 g/cm^-3 with R(R_w) = 0.033 (0.034). While compounds 1 and 2 contain almost identical 1-D metal oxide chains composed of corner-sharing VO₄ tetrahedra with one oxygen atom from each tetrahedron bound to the copper complex, complex 3 consists of 1-D chains with a Cu(C₁₀H₈N₂)₂ fragment bonded to every other VO₄. Temperature-dependent magnetic measurements of 1 exhibit a maximum at 20 K, while 2, which possesses well-separated Cu²⁺ centers, displays Curie-Weiss behavior from 5 to 300 K.