Synthesis and two-dimensional correlation infrared spectroscopy study of an organic-inorganic hybrid compound constructed by [Mo5P2O23] and Cu-imidazole components

A novel compound, (Himi)(H3O) [Cu(imi)2]2[P2Mo5O23]·H2O 1 (imi = imidazole), was synthesized by hydrothermal method and characterized by X-ray single analysis, ESR spectrum, one-dimensional (1D) infrared spectroscopy and two-dimensional (2D) correlation infrared spectroscopy under thermal and magnetism perturbation. Crystal data for the compound 1: orthorhombic system, space group Pnma, a = 14.580(3) Å, b = 21.073(4) Å, c = 16.664(3) Å, Z = 4. It consists of the Mo-Cu building-blocks [Cu(imi)4]2[P2Mo5O23]2−, protonated imidazole cations and water molecules. In the Mo-Cu building-blocks, [Mo5P2O23]6− clusters are linked by {Cu(imi)4}2+ group to form a two-dimension parallelogram griddling structure. From the 2D IR correlation spectroscopy analyses, it is discovered that the intensity changes of MoO and P-O band are sensitive to the temperature variation, whereas the Mo-O bond linking to Cu2+ can be remarkably affected by the magnetism variation. Furthermore, the intensity changes of P-O bands occur prior to that of the MoO band during the temperature elevation.