[Structural and spectral study of a novel rare-earth and 3-bi-pyridine acid polymer]

A novel zero-dimension coordination polymer Gd2 (In)6 (H2O)4 (1) (In = 3-bipyridine acid) was synthesized under hydrothermal condition. By the analysis of single-crystal X-ray diffraction, the structure of the compound is that two Gd atoms connect with zero-dimension bi- nucleus cluster by the bridged carboxylate of four Ins. Based on the determination of the structure, the 2D correlation FTIR spectra with the perturbations of magnetism and thermal was applied. Under the perturbations of temperature, the vibration of the carboxylate has the very strong response, which is related with the strong coordinating ability of the carboxylate. At the same time, due to the different coordinated mode of the carboxylate with Gd, the response of Gd--O bonds is different under the temperature perturbations. Under the perturbations of magnetism, the vibration of the carboxylate has also the very strong response, which may be related with one-negetive charge of the carboxylate. The 2D correlation ultraviolet spectral with the perturbation of magnetism were investigated. Compared with one-dimension ultraviolet spectral, the transition of the pi electrons in bi-pyridine ring and the charge transition from ligand to the metal have the very strong response. At the same time, the fluorescence spectral and TGA were studied.