Spectroscopic Study Of Several Kinds Of Transition Metal-organic Coordination Complexes

Metal-organic coordination complexes as coordination chemistry and supramolecular chemistry of important cross-cutting research areas, it has brought to the domestic and foreign expert's attention in the new material's research, gradually. Metal-organic coordination complexes has a wide range of potential applications in gas adsorption, optics, catalysis, molecular recognition, molecular devices and other fields because of its special topological structure. At present, it has been the hot research fields in coordination chemistry, materials chemistry, structure chemistry, supramolecular chemistry, and analytical chemistry. At present, the study of the metal organic coordination materials focuses on their design, their preparation and the characterization of their crystal structure. In this paper, several kinds of metal-organic coordination compounds were synthesized. Fourier-transform infrared (FTIR), Raman and Ultraviolet-visible (UV-Vis) spectra of the ligand and its metal-organic coordination compounds were investigated, respectively. The major contributions of this work are as follows:1. Spectroscopic study of transition metal ions and 4, 4'-bipyridine complexes In this paper, FTIR, Raman and UV-Vis spectra of 4,4′-bipyridine (4,4′-BPy) and its metal-organic coordination compounds were investigated, respectively. As 4,4′-BPy molecule is coordinated to metal ion, a new M-N coordination bond is formed. Consequently, changes in some vibration frequencies of 4,4′-BPy occur in the complexes. For example, in FTIR the absorption band of the composite vibration band,ν(C-C) andν(C-N), for 4,4′-BPy at 1589 cm-1 blue-shifts to 1608, 1608 and 1612 cm-1 for the complexes, respectively. In the Raman spectra, the same change trend of the corresponding C-N, C=C, and C-C bond were observed.2. Spectroscopic study of transition metal ions and 4-mercaptopyridine complexesFTIR, Raman and UV-Vis spectra of 4-mercaptopyridine and its metal-organic coordination compounds were investigated, respectively. The sulfur atom in the ligand is coordinated to transition metal ions. In the FTIR spectra, the vibration band of ring breathing, for 4-mercaptopyridine at 991 cm-1 blue-shifts to 1007 cm-1 for the complexes. In the Raman spectra, the same changes were observed. Compare the UV-Vis spectrum of 4-mercaptopyridine with its five kinds of complexes(Co-MPY, Ni-MPY, Cu-MPY, Ag-MPY, Cd-MPY) when the same ligand was coordinated to different kinds of metal ions, the electronic absorption spectra of complexes varied greatly, due to the different extranuclear electron distribution of metal.3. Spectroscopic study of transition metal ions and 1, 2-trans-(4-pyridyl)ethene complexesFTIR, Raman and UV-Vis spectra of 1,2-trans-(4-pyridyl)ethene (DPE) and its metal-organic coordination compounds were investigated, respectively. As DPE molecule is coordinated to metal ion, the changes of spatial symmetry of DPE, a new M-N coordination bond is formed. Consequently, changes in the vibration frequencies of the C-N, C=C, C-C and C-H bonds occur in the complexes. In FTIR spectra the absorption band of the composite vibration band,ν(C-C) p,δ(C-N) p,δ(C-H), for 1,2-trans-(4-pyridyl)ethene at 1595 cm-1 blue-shifts to 1614, 1614 and 1605 cm-1 for the complexes. In the Raman spectra, the same change trend of the corresponding C-N, C-C, and C-H bond were observed.4. Spectroscopic study of transition metal ions and 4-aminothiophenol complexesFTIR, Raman and UV-Vis spectra of 4-Aminothiophenol (PATP) and its metal-organic coordination compounds were investigated, respectively. In FTIR spectra, for the complexes the most powerful spot appeared at 1384 cm-1. The vibration bandδ(S-H) andν(S-H), for PATP at 910 and 2553 cm-1, they are disappeared in three kinds of complexes. The sulfur atom in the ligand is coordinated to transition metal ions. Compare the Raman spectrum of 4-Aminothiophenol with its three kinds of complexes (Zn-PATP, Ag-PATP, Cd-PATP). The vibration band,ν(M-S), for three kinds of complexes at 213 cm-1, it is not found in PATP. This has proved that the sulfur atom in the ligand is coordinated to transition metal ions.