Study On The Metal Complexes Constructed By 2-phenylimidazo[4, 5-f]1, 10-phenanthroline Ligand

In this paper,14 rare earth complexes containing benzoic acid and 2-phenyl-imidazo[4,5-f]1,10-phenanthroline (PIP) were prepared and characterized by chemical and elemental analysis, infrared spectroscopy and X-ray diffraction technique on the compositions and structures. Thermal stabilities of these solid complexes were studied by using TG-DTG Their thermal decomposition mechanisms were explored. The beginning decomposition temperatures of 14 kinds of complexes are between 608 K and 628 K. It is indicated that these complexes have better thermal stabilities. With the use of automated data processing RBC-II rotating bomb calorimeter measurement system, the constant-volume combustion energies of all the complexes were determined at 298.15 K. The standard molar enthalpies of combustion and standard molar enthalpies of formation at 298.15 K were derived.In addition, based on the PIP ligand, CdCl2·2.5H2O and Zn(Ac)2·2H2O, two complexes [Cd(PIP)2Cl2]-2CH3OH and [Zn(PIP)3]2·9H2O were successfully synthesized by hydrothermal method in alcohol-water system, respectively. The compositions and structures of the obtained complexes were analyzed by elemental analysis, IR and single-crystal X-ray diffraction. The results of the crystal structure analysis show that Cdn central ion is coordinated by two PIP ligands and two chloride ions, and the two PIP ligands present the shape of letter "V". While ZnⅡcentral ion is formed coordinate bonds just with three PIP ligands, it is interesting that the same three ligands arranged around the central ion shaped like the three laminas of the fan. This kind of coordinated pattern has not been reported in the related literatures. Fluorescence emission spectrum of the two complexes were obtained at room temperature, as a result, it is shown that the two complexes have strong fluorescence intensities. They are expected to be applied as good blue or green fluorescent materials.By use of dicarboxylic acids, PIP and transition metals ions (Mn" and CdⅡ) were constructed to another two new complexes. Thereinto, the coordination polymer [Cd(succ)PIP]n was gained from the Cd" ions, succinate anion (succ) completely lost two protons and PIP ligand. Similarly, their compositions and structures were better studied with elemental analysis, IR spectrum and single-crystal X-ray diffraction. At room temperature, the fluorescence properties of the two complexes were investigated and found that the solid complex [Mn(1,2-bdc)(PIP)2]-H2O (1,2-bdc is phthalic anion), is almost no fluorescence, but the coordination polymer[Cd(succ)PIP]n prensents strong fluorescence atλem=493 nm under the UV excitation wavelengthλex=298 nm, which is clearly demonstrated that this new coordination polymer may be the candidate of blue fluorescent material.