Design, Synthesis And Structure Of Coordination Polymers And Ploynuclear Complexes With Bridging Schiff Base Ligands

In recent years, the research of coordination polymers and polynuclear complexes have become one ofthe most active fields due to their favorable potential application in the fields of luminescent, electricity,adsorption, gas storage and catalysis et. al. Azide ion N^-3, thiocyanate ion SCN^-, dicyanamide ion [N（CN）₂]-not only have abundant bridging ligand mode, but also have the characteristics of effective transfermagnetic coupling, which are often used as a short bridge connection paramagnetic metal center to buildmolecular magnetic materials.In this paper, we have synthesized three asymmetric Schiff base ligands, through reacting with transitionmetal salt and rare earth metal salt reaction, using a variety of bridging ligands such as: halogen ion X-（Cl^-,Br^-）, azide ion N₃^-, thiocyanate ion SCN^-, dicyanamide ion [N（CN）₂]-. The12coordination polymers andpolynuclear complexes were synthesized. The main content as following:（1） Through condensing3-carboxysalicylidene and N, N-dimethyl ethylenediamine, one new Schiffbase H₂L1[H₂L1=（E）-3-（（2-（dimethylamino）ethylimino）methyl）-2-hydroxybenzoic acid], using theligand, we have synthesized three copper complexes [Cu₂（HL1）₂（N₃）₂]（1）,[Cu₄（L1）₂（N₃）₄]_n（2） and[Cu₄（L1）₂（N₃）₂（H₂O）₂]·4H₂O （3）, complex2is the1D chain coordination polymer. Their crystal structureswere characterized by IR, UV, TG-DTA analysis and X-ray diffraction.Use the same ligand H₂L1and cobalt（II） salt, under the right conditions to add some ancillary ligands byintroducing proper bridging ligand sodium azide, obtained the polynuclear complexes[Co₄（L1）₂（N₃）₄（H₂O）₄]·2H₂O （4）.Ligand H₂L1and Cu（II） salt, by introducing proper bridging ligands thiocyanate, got a1D chaincoordination polymer [Cu（HL1）（NCS）]_n（5） and a2D layer coordination polymer{[Cu₂（L1）（H₂O）（NCS）]₂·DMF}n（6）.Ligand H₂L1react with Cu（ClO4）₂·6H₂O, by introducing proper bridging ligand diamino sodium cyanide,got a1D chain coordination polymer [Cu（HL1）（dca）]_n（7）（dca-=dicyanamide）. The structures weredetermined and characterized by IR, UV-vis, X-ray single crystal diffraction and thermal analysis.（2） Through condensing3-carboxysalicylidene and N^-methyl^-1,3-propanediamine, we have prepared anew kind of asymmetric Schiff base ligand H₃L2[H₃L2=（E）-2-hydroxy-3-（（3-（methylamino）propylimino）methyl）benzoic acid], added some appropriate bridging ligands （NH₄SCN, Nadca） and Cu（II） salt, have synthesized three copper complexes [Cu₂（L2）₂Br₂]·H₂O （8）,[Cu₂（L2）（CH₃OH）₂（NCS）]_n（9）,[Cu₄（L2）₂（CH₃OH）₂（dca）₂]_n（10）, complex9is a1D chain coordinationpolymer, complex10is a2D layer coordination polymer. Their crystal structures were characterized byinfrared spectra, UV-vis spectra and X-ray single crystal diffraction.（3） Through condensing3-carboxysalicylidene and thiosemicarbazide, a new Schiff base ligand H₃L4[H₃L3=（E）-3-（（2-carbamothioylhydrazono）methyl）-2-hydroxybenzoic acid]. Using the ligand react withCu（CH₃COO）₂·4H₂O and NH₄SCN, through the molecular self-assembly method got a mononuclearcomplex [Cu（HL3）（NCS）]·2CH₃OH （11）. At the same time, using the ligand and Cu（NO₃）₂·3H₂O andDyCl3·6H₂O, got a transition-rare earth mixed different metal three-nuclear complexe[Cu₂Dy（L3）₂（DMF）₄（NO₃）] DMF （12）, the structures were determined through the X-ray single crystaldiffraction.