Exploratory syntheses and structural characterizations of three organic–inorganic hybrid polyoxomolybdate frameworks linked by M(II)-Lnunits (M = Ni, Co, Zn; L = 2,2′-biimidazole)

Three new polyoxomolybdate compounds, {[Ni(H2biim)2(H2O)](Mo3O10)} n (1), [Co(H2biim)2(Hbiim)]2(H2Mo8O26)](H2O)4 (2), and {[Zn(H2biim)2(H2O)][Mo8O28(MoO2(H2biim)2)2](H4biim) (3) (H2biim, 2,2′-biimidazole), were designed and synthesized under hydrothermal conditions. X-ray diffraction analysis reveals that 1 is a snake-shaped chain consisting of asymmetric blocks of {Mo3O10}, in which the ratio of the octahedra {MoO6} and square pyramids {MoO5} is 1 : 2. Compounds 2 and 3 exhibit different structures, although similar synthetic environments (including pH, temperature, and reaction time) were employed. In 2, the cluster of H2Mo8 is decorated by two fragments of Co(H2biim)2(Hbiim)+ via the organic bridge of Hbiim−. Compound 3 consists of one γ-Mo8 , capped by two fragments of {MoO2(H2biim)2)2}2+ via terminal oxygens.