Studies of the oxovanadium(IV)-oxalate system: Syntheses and crystal structures of binuclear (Ph(4)P)(2)[(VO)(2)(H2O)(2)(C2O4)(3)]center dot 4H(2)O and of the one-dimensional chain material, (Ph(4)P)[VOCl(C2O4)]

The hydrothermal reactions of (Ph(4)P)[VO2Cl2] and H2C2O4 at 150 and 125 degrees C yield (Ph(4)P)(2)[V2O2(H2O)(2)(C2O4)(3)]. 4H(2)O (1) and (Ph(4)P) [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 Ph(4)P(+) cations occupying regions between {[VOCl(C2O4)](-)}(infinity) spiral chains. The structure of the one-dimensional anionic chain exhibits V(IV) octahedra bridged by bisbidentate oxalate groups. Crystal data: 1 . 4H(2)O, monoclinic P2(1)/n, a=12.694(3), b=12.531(3), c=17.17(3) Angstrom, beta=106.32(2)degrees, V=2621.3(13) Angstrom(3), Z=2, D-calc=1.501 g cm(-3), structure solution and refinement converged at a conventional residual of 0.0518; 2, tetragonal P4(3), a=12.145(2), c=15.991(3) Angstrom, V=2358.7(12) Angstrom(3), Z=4, R=0.0452.