Synthesis and characterization of two {Mo 6 }-based/templated metal–organic frameworks

Here, we report two novel POM-based MOFs: a nano-caged hybrid compound [Ni2(BIMB)2(MoVI4MoV2O19)] (1), whose cages are based on [Mo6O19]4- units and a [Mo6O19]2--templated framework [Zn4(BIMB)4(PO4)2(Mo6O19)][middle dot]2H2O (2) (BIMB = 1,4-bis(1-imidazolyl)benzene). According to topological analysis, the first is a 3D (4,6)-connected self-penetrating framework with polycatenanes motif. In contrast, the second metal-organic framework has no interpenetration for the templated [Mo6O19]2- occupying the cavity. The UV-vis absorption spectrum of 1 was investigated to prove the existence of MoV atoms and the typical peak at 577 nm can be attributed to MoV [rightward arrow] MoVI charge transfer. Furthermore, the diffuse reflectivity spectrum shows that its band gap can be assessed as 3.06 eV, which can be regarded as a wide gap semiconductor. Additionally, cyclic voltammogram of compound 1 shows two redox peaks in the range of 0-800 mV in H2SO4 aqueous solution.