Studies On The Mixed-ligand Metal Coordination Compounds Including Diacid And Diimine Ligand

Metal coordination polymers, especial diacid metal coordination polymers have received extensively attentions in recent years, not only due to their various intriguing topological structures but also their potential applications as new functional materials in host-guest chemistry, magnetic material, molecular sieve, molecular recognition, ion exchange, heterogeneous catalysis, non-linear optical and so on.Based on dicarboxylate ligand having richful type of coordination modes, the research topic of this paper is developing new diacid meatl coordination polymer. In this paper, 8 coordination compouds have been synthesized by means of conventional solution reaction, diffusion or hydro-thermal method, using dicarboxylate ions including oxalate(ox), succinate (suc), terephthalate (bdc) as the first ligand, and the bidentate chelating ligands 1, 10-phenanthroline (phen) or 2,2'- bipyridyl (2,2'-bipy) or bridging ligand 4,4'- bipyridyl (4,4'- bipy) as the second ligand. Six of these compounds are novel meatl coordination compounds. All the synthesized compounds were characterized by the IR and element analyses. The structures of these compounds have been determined by X-ray single crystal diffraction method. For partial compounds, the thermal properties were analyzed by thermo-gravimetric (TG) and differential thermal analysis (DSC), and the fluorescent properties in solid were also studied. The main contents and results in this paper are as follows:1. Four diacid and diimine mixed-ligand compounds and one terephthalic polymer were synthesized, they are: [Cu₂(phen)₂(ox)Cl₂] (1); [Cd₃(phen)₂(suc)₃]·4H₂O (2); [Zn(bdc)(H₂O)₂] (3); [Zn(phen) (bdc)] (4); [Zn(2, 2'- bipy)(bdc)(H₂O)]·H₂O (5). Except for 1, the left compounds are coordination macromolecule polymers.2. Three terephthalate coordionation pore polymers were isolated. They are : [Zn(bdc) (H₂O)]·(DMF) (6); [Ca (bdc)·(4, 4'-bipy)]·2H₂O (7) ; [Cd(2, 2'- bipy)(bdc)]·( 2, 2'-bipy) (8).3. All these polymers are stable in room temperature. The TG analysis of polymers 2, 4 - 8 reveals that the decomposition temperatures of these polymers all are over 170℃. And these polymers are more stable than their simple compositions.4. The polymers 2, 4 - 8 at the solid state show fluorescent emission bands around 462 nm, 506 nm, 506 nm, 465 nm, 476 nm and 462 nm, resectively, under 330～390 nm light excitation. The shapes of emission spectra are similary for the polymers with the similary ligands. Polymer's structure influence emission intensity. The results indicated that these compounds be possible fluorescent materials.