Hydrothermal Syntheses And Crystal Structures Of Transitional-metal-complex-modified Polyoxomolybdate

The organic–inorganic hybrid compounds, which are expected to be endowed with enhanced or combined functionalization of both organic and inorganic substructures has been focused on the richness of their structures and special properties in the fields of catalysis and materials science as well as in biology, magnetism, nonlinear optics and medicine. Although the polymolybdate and metal complex has recieved considerable attention, it still remains a challenge to synthesize new compounds and investigate the potential properties further. In this paper,three novel polyoxometalate-based organic–inorganic hybrid compound, [Co(bipy)₃]₂[Mo₆O₁₉] [β-(H₂Mo₈O₂₆)] ·4H₂O 1, [Ni(phen)₃][Mo₆O₁₉] 2 and [(CuO₃ bipy)₂(SeO₃)₂(Mo₄O₁₃)(Mo₂O₅)]₃ have been hydrothermally synthesized through modifying synthetic conditions and starting material. Structures of the three complexes have been determined by single crystal X-ray diffraction and the influencing factors on polyoxometalate-based organic-inorganic hybrid compound Mo-O framework have been discussed. Other characterizations for these three complexes by elemental analysis, IR, XPS and thermal analysis have also been described. Both compound 1 and 2 are bimetallic cluster complexes. Compound 1 represents the first example that racemic complexes coexisting with two kinds of polyoxomolybdate anions in the same crystal architecture, which should be of rare chance that four kinds of complexes crystallizes into a compound. Compound 2 contains centrosymmetric [Mo₆O₁₉]^2- hexamolybdate anions, which are built up from distorted MoO₆ units by edge-sharing. The nickel atom in the [Ni(phen)₃]²⁺ cation adopts distorted octahedral coordination with three N, N ′ -bidentate 1,10-phenanthroline (phen) ligands. The crystal packing is stabilized by some weak π–π stacking interactions between neighboring phen ligands and C—H … O interactions. The Ni atom occupies a special position with twofold symmetry. 3-D heteropolymolybdate compound 3 with capping selenite through Ï€-Ï€ stacking hydrogen bond.