| As imine, a kind of common organic, are facility to synthesis and structural varieties, The imine complexes, using imine to coordinate with different metal ions, have attarcted so much attention that people have used them in so many fields. The kind of metal ions and structure of ligand decide the application of these complexes. Metals of IIB group usually enhance these comlexes’ s rigidity and coplanarity when they coordinated with various imine. Meanwhile the way of electron transition won’t change due to their full-outer electronic structure. The IIB group’s metals are usually used to synthesized complexes which was applied as vairious of fluorescent material. So it’s difficult to chose reasonable imine ligand that may exhibit fascinating fluorescent property after according to imine. Among the synthetic process, we have synthesized three ligands with the compound of 2-acetylpyridine, 2-quinolinecarboxaldhyde, o-methylaniline o-phenylenediamine and 1,2-cyclohexanediamine. The three ligands are 2-{1-[(2-methylphenyl)imino]-ethyl} pyridine(L0), N’-bis(2-quinolinecarboxaldhydin)-benzene-1,2-diamine(L1) and N1,N2-bis(quinolin-2-ylmethylene)cyclohexane-1,2-diamine. Then, the ligands were used to react with different IIB metal chloride and eight Schiff base complexes(Zn1~Zn2, Cd1~Cd3, Hg1~Hg2) are obtained. After synthises, we have used NMR, IR and elemental analysis, single crystal X-ray diffraction analysis to characterize the structure of these compounds, All compounds are obtained crystal structure. The results show that complexes Cd1~Cd3 have 1D chain structure, others are simple complexes. It’s interesting that the structure of ligand changed, when reacted with different metal chloride under various condition. The fluorescence emission spectrum, lifetime of ligand and complexes are obtained and we explained which lead to the difference among all the compouns.The fluorescent properties of the two complexes Cd1 and Cd2 were characterized in both solid state and in different polar solvents. The results show that complexes Cd1 and Cd2 exhibit blue fluorescence emission(ca. 390 ~ 433 nm) in CH3 OH, CH3 CN and CH2Cl2, indicating that the coordination polymers have weak solvent effect. The emission spectra of complexes Cd1 and Cd2 at 298 K are centered at 440 and 473 nm respectively in solid state. Comparing to the emission spectra in solutions, the emission spectra in solid-state undergo obvious red-shift. The lifetime of complexes Cd1 and Cd2 are relatively long(ca. 19.08 ~ 60.20 μs) at room temperature.Additionally, the fluorescent properties of the compounds L1, Zn1, Cd3, Hg1 and Hg2 were characterized in both solid state and different polar solvents. The results show that L1, Zn1, Cd3, Hg1 and Hg2 display different change low in both solid state and different polar solvents because of diverse structure. Compounds L1 and Zn1 show blue shift in emission spectra with increasing solvent polarity, Comparing that complexes Cd1, Hg1 and Hg2 are red shift as solvent polarity increases. Then, the emission spectra of complex Hg1 in water with different p H were characterized, considering that the structure of ligand of complex Hg1 is special. The resulting show that intensity of emission spectra increase in acid or base. Finally the lifetime of ligand L1, Zn1, Cd1~Cd3, Hg1 and Hg2 were characterized at the same condition.Eventually, the fluorescent properties of the compounds L2, Zn2 and Cd4 were characterized in CH2Cl2. After the ligand coordinate to metal ion, the complex show red shift in emission spectra. The lifetime of eleven compounds are short both in solid state and solutions, in the range of microsecond. And all compounds show various change rule. |
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