Synthesis and Crystal Structure of Potassium Triethylenetetraaminehexaacetatodi [Oxo-vanadium(Ⅳ)] Hexahydrate, K_2[V_2O_2(ttha)]·6(H_2O)

1 INTRODUCTION Interest in vanadium in the physiology and biochemistry has promoted enormously in recent years. Vanadium is known to exist in alternative nitrogenase metalloenzyme systems fixing nitrogen. It is also found to participate in biological processes exhibiting mitogenic behavior and enzyme inhi- bition[1]. Up to date, several crystal structures have been reported about vanadium with carboxylic or polycarboxylic acid[2, 3]. However, very few struc- tures of vanadium complexes …

Synthesis and Crystal Structure of Potassium Triethylenetetraaminehexaacetatodi [Oxo- vanadium(Ⅳ)] Hexahydrate, K2[V2O2(ttha)]·6(H2O)

The title complex, potassium triethylenetetraaminehexaacetatodi [oxo-vanadium (Ⅳ)] hexahydrate K2[V2O2(ttha)](6(H2O), was synthesized in aqueous solution and its crystal structure has been determined by X-ray diffraction. The complex belongs to a triclinic system, space group Pī with a = 6.645(1), b = 9.870(2), c = 13.263(3)(A。), α = 70.68(3), β = 76.27(3), γ = 71.66(3)°, V = 770.5(3)(A。)3, Mr = 808.58, Dc = 1.743 g/cm3, Z = 1, μ = 0.968 mm－1, λ(MoKα) = 0.71073 (A。) and F(000) = 416. The final R = 0.0465 and wR = 0.1091 for 2974 observed diffractions with I ≥ 2σ(I). In the complex, the V atom is octahedrally coordinated to the oxo ligand, two N and three O atoms of the triethylenetetraaminehexaacetic (TTHA) ligand. All of the ten chelating sites are coordinated to the two vanadium atoms, and the coordination octahedron is distorted. Each [V2O2(ttha)]2－ ion is further connected by the K+ ions through carboxyl groups of TTHA6－ ion, forming a two dimensional network structure.