POLYOXO ALKOXIDES OF VANADIUM - THE STRUCTURES OF THE DECANUCLEAR VANADIUM(IV) CLUSTERS [V10O16(CH3CH2C(CH2O)3)4]4- AND [V10O13(CH3CH2C(CH2O)3)5]-

The hydrothermal reaction of a mixture of vanadium oxides with CH3CH2C(CH2OH)3 in the presence of NH4Cl yields (NH4)4[V10O16{CH3CH2C(CH2O)3}4].4H2O (I). In contrast, the reaction of vanadium oxides with the same ligand, using Et4NCl as mineralizer, yields (Et4N)[V10O13{CH3CH2C(CH2O)3}5] (II). Both I and II exhibit structures based on the decavanadium core, {V10O28}. While 12 doubly and triply bridging oxo groups of the [V10O28]6- prototype are replaced by alkoxy oxygens of the ligands in I, 15 doubly and triply bridging oxo groups are replaced in II. In addition to the incorporation of alkoxy ligands into the {V10O28} core, I and II are unusual in that the vanadium sites exhibit the V(IV) oxidation state rather than V(V) as observed for the parent core. The relatively small structural distortions associated with this reduction of the core are noteworthy. Crystal data for (NH4)4[V10O16{CH3CH2C(CH2O)3}4].4H2O (I): space group, C2/c; a = 17.320 (2) angstrom; b = 24.904 (3) angstrom; c = 12.430 (2) angstrom; beta = 106.32 (1)-degrees; V = 5146 (3) angstrom 3; Z = 2; D(calc) = 1.840 g/cm3; structure solution and refinement based on 4053 reflections, R = 0.042. Crystal data for (Et4N)[V10O13{CH3CH2C(CH2O)3}5] (II): space group, P2(1)/c; a = 12.290 (2) angstrom; b = 19.115 (2) angstrom; c = 23.701 (4) angstrom; beta = 98.80 (1)-degrees; V = 5502 (2) angstrom 3; Z = 4; D(calc) = 1.815 g/cm3; 4436 reflections, R = 0.079. An analogous compound to II, (Me4N)2/3(Et4N)1/3[V10O13{CH3C(CH2O)3}5].0.69H2O (III) was prepared in a similar fashion. Crystal data for (Me4N)2/3(Et4N)1/3[V10O13{CH3C(CH2O)3}5].0.69H2O (III): space group, P2(1)/n; a = 12.235 (2) angstrom; b = 22.484 (6) angstrom; c = 53.439 (13) angstrom; beta = 92.61 (2)-degrees; V = 14685 (6) angstrom 3; Z = 12; D(calc) = 1.913 g/cm3; 11 994 reflections, R = 0.0851.