Hydrothermal syntheses, crystal structures, and properties of two new organic-inorganic hybrid compounds based on polyoxometalates and pyridyl imidazole

Two new organic-inorganic hybrid compounds based on polyoxometalates (POMs) and pyridyl imidazole, [Co(pyim)(3)][HPW12O40] center dot 4H(2)O (1) and [Ni(pyim)(3)](2)[(PMoMo11O40)-Mo-V-O-VI] center dot 1.5H(2)O (2) (pyim = 2-(2-pyridyl)-imidazole), have been hydrothermally synthesized. The structures of 1 and 2 were determined by single-crystal XRD. Other characterizations were performed by thermogravimetric, infrared spectra, and ultraviolet excitation and emission spectra. Interestingly, (H2O)(4) clusters exist in the structure of 1, which connect organic ligands by hydrogen bonds to sheets, while connecting POMs to other sheets, thus forming the supramolecular sandwich structure by inorganic layer and organic layer spaced at intervals. In the structure of 2, two [(PMoMo11O40)-Mo-V-O-VI](4-) anions connect by the van der Waals force, then the dipolymers are further linked by [Ni(pyim)(3)](2+) by hydrogen bonds to form the supermolecular structure.