| Carboxylate group has changeable coordination fashions and,therefore,the structures of the complexes derived from carboxylic acids are susceptible to condition.This promises a feasibility to obtain the complexes with different structures and properties from the reactions of the same metal ion and ligand.In particular,the polycaboxylic ligands,for the diversities of bridging segments in the rigidity and geometry,have been extensively used as bridging linkers for building the polymeric coordination compounds with intriguing structural topologies.In comparison with the flexible aliphatic acids,pyridine-dicarboxylatic acids possess not only the characters of dicarboxylate ligands,but also the rigidity based on pyridyl ring and the coordination of one-paired electrons provided by nitrogen,so they show the more prosperous coordination fashions and selectivity toward metal ions.Apparently,this favors control of the structures of coordination polymers.The dissertation,in the filed of molecule design and self-assembly of supramolecular chemistry,using aliphatic dicarboxylic acids and pyridinedicarboxylic acids as main ligands,and some other azo-donors as auxiliary ligands, presented the synthesis of a series of new coordination polymers by hydrothermal reactions.The structures of the products were determined by X-ray single crystal,powder diffractions,and infrared spectroscopy.Moreover,the photoluminsent properties of some coordination polymers have been investigated.We synthsized 20 products,which would be classified into four parts according to the reaction conditions for preparing these complexes.The first part reports four coordination polymers {[Ni(2,6-PDC)2][Ni(phen)2(H2O)2]·7 H2O}n(1),[Cu(2,6-PDC)(Imz)]n(2),[Cu(2,5-PDC)]n(3) and {[Cd(3-PYC) (1,4-BDC)0.5·2H2O]·2H2O}n(4),which were synthesized by hydrothermal reactions of pyridine-dicarboxylic acid,as main ligand,and some other ligands,as second ligand,with transition metal salts.X-Ray single crystal analysis revaled that the complexes are assembled in 0D(1-3) or 1D(4) and that in the crystal packing of 1-4 exist the rich hydrogen bonds and p-p interactions,which are dominative over the assembly of coordination polymers.In this part,we elucidate the function of these no-covalent interations on crystal packing and,meanwhile,probe the luminescence of the d10 Cd(Ⅱ) complex 4.In the second part,we systematically investigated the comformation coordination of alphatic diacid ligands and pyridinedicarboxylic acids.At first,for aliphatic dicarboxylic acids, we obtained three isomophic 3D rera earth metal-edipate complexes, {[Ln2(μ3-ADI)2(μ2-ADI)·(H2O)4]·H2O}n(Ln=Er,5;Tb,6;Eu,7),consisting of the inclined interpenetrated(4,4) coordination networks,in the presence of pyridine-2,3-dicarboxylic acids as template and a 3D complex,[Nd2(μ3-SEB)3·(H2O)2]n(8) in the absence of template.Immediately, we obtained another two complexes[Nb(2,5-PDC)(2,5-HPDC)]n(9) and ([Tb(2,5-PDC)(2,5-HPDC)]n(10),by the hydrothermal reactions without adding aliphatic acids and five structurally comparable mixligand complexes[Tb(2,5-PDC)(OX)0.5(H2O)2]n(11), {[Nd(2,5-PDC)(SUC)0.5(H2O)]H2O}n(12),[Nd(2,5-PDC)(ADI)0.5(H2O)]n(13), [Gd(2,5-PDC)(ADI)0.5(H2O)]n(14) and[Nd(2,5-PDC)(SUB)0.5(H2O)]n(15) with adding aliphatic acid ligands.As comparison,we used the 1,4-benzenedicarboxylic acid,as second ligands,in the place of aliphatic acids to react with H2PDC and rare earth metal,and consequently ontained the more complicated coordination polymers[Nd(2,5-PDC)(1,4-BDC)0.5·(H2O)]n(16), [Nd(2,5-PDC)(1,4-BDC)0.5·(H2O)]n(17) and[Nd3(2,6-PDC)2(1,4-BDC)2(μ3-OH)·(H2O)]n(18). Structural analysis on the solid structures of these products revealed that the second ligands have crucial influence on the construction of complexes,for example,we found that the rigid ligands are more dominative than the flexible ones.Finally,based on Lewis' hard-soft base-acid theory(HSBA),we took the advantage that the rare earth metal ions are harder than the common-valence transition metal to synthesize two mixligand bimetallic complexes,[NdZn(2,5-PDC)2Cl·(H2O)2]n(19) and [EuZn(2,5-PDC)2(1,4-BDC)0.5·(H2O)2]n(20).The isolation of 19 and 20 exeplifies a strategy of controlling the construction of coordination polymers in virtue of the chemical reactivity of ligand.In the mean time,it illustrate a way to prepare mixmetal complexes and so extends the applications of metal-organic framework compounds into a new scope. |
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