Assembly of [V15Sb6O42(H2O)]6− cluster shells into higher dimensional aggregates via weak Sb⋯N/Sb⋯O intercluster interactions and a new polyoxovanadate with a discrete [V16Sb4O42(H2O)]8− cluster shell

Abstract

Systematic variation of reaction parameters such as reaction temperature and concentration of the amine under solvothermal conditions using NH4VO3, Sb2O3, CoCl2·6H2O and tris(2-amino)ethylamine (tren) led to the formation of three new antimonato polyoxovanadates: {Co(tren)(H2O)}3[V15Sb6O42(H2O)]·H2O (1), {Co2(tren)3}2{Co(tren)(en)}[{V15Sb6O42(H2O)(Co(tren)2)}V15Sb6O42(H2O)]·xH2O (x ≈ 11) (2) and {Co(tren)(trenH2)}2[V16Sb4O42(H2O)]·6H2O (3). The structures of 1 and 2 are composed of [V15Sb6O42(H2O)]6− cluster anions, which weakly interact with each other through relatively short Sb⋯O bonds. The transition metal complex {Co(tren)(H2O)}2+ acts as a counter ion in 1. In 2 charge neutrality is achieved by the two cations {Co2(tren)3}4+ and {Co(tren)(en)}2+ which are isolated and by {Co(tren)2}2+ being bound to one cluster anion. The main structural motifs in compound 3 are the [V16Sb4O42]8− cluster shell and isolated {Co(tren)(trenH2)}4+ cations. The structures of all three cluster anions can be derived from the {V18O42} archetype by replacing three VO5 moieties by three Sb2O3 units in 1 and 2 and by substituting two VO5 square pyramids by two Sb2O3 groups in 3.