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Studies of the oxovanadium(IV)—oxalate system: syntheses and crystal structures of binuclear (Ph4P)2[(VO)2(H2O)2(C2O4)3]·4H2O and of the one-dimensional chain material, (Ph4P)[VOCl(C2O4)]

1996; Elsevier BV; Volume: 250; Issue: 1-2 Linguagem: Inglês

10.1016/s0020-1693(96)05239-5

1873-3255

José Salta, Charles J. O’Connor, Sichu Li, Jon Zubieta,

Vanadium and Halogenation Chemistry

The hydrothermal reactions of (Ph4P)[VO2Cl2] and H2C2O4 at 150 and 125°C yield (Ph4P)2[V2O2(H2O)2(C2O4)3]·4H2O (1) and (Ph4P)[VOCl(C2O4)] (2), respectively. The structure of the molecular anion of 1 consists of a binuclear unit of oxovanadium(IV) octahedra bridged by a bisbidentate oxalate group. The VO6 coordination geometry at each vanadium site is defined by a terminal oxo group, an aquo ligand, and four oxygen donors — two from the bisbidentate bridging oxalate and two from the terminal bidentate oxalate. The structure of 2 consists of discrete Ph4P+ cations occupying regions between [VOCl(C2O4)]−∞ spiral chains. The structure of the one-dimensional anionic chain exhibits V(IV) octahedra bridged by bisbidentate oxalate groups. Crystal data: 1·4H2O, monoclinic P21/n, a = 12.694(3), b = 12.531(3), c = 17.17(3) Å, β = 106.32(2)°, V = 2621.3(13) Å3, Z = 2, Dcalc = 1.501 g cm−3, structure solution and refinement converged at a conventional residual of 0.0518; 2, tetragonal P43, a = 12.145(2), c = 15.991(3) Å, V = 2358.7(12) Å3, Z = 4, R = 0.0452.