Preparation And Properties Of Coordination Polymers Based On In Situ Ligand Formation Reaction

The study is based on two kinds of in situ ligand synthesis reaction-the in situ acylation reaction between the organic aromatic polycarboxylic acids and N2H4·H2O as well as the in situ cyclizative condensation reaction between o-phenylenediamine and oxalic acid.In this article,we synthesized thirteen coordination polymers as well as two acylhydrazide molecules based on the above two reactions via the hydro(solve)thermal self-assemblies between metal salts and organic ligands.We also discussed the influence of different synthesis conditions,such as,pH and temperature and so on.Furthermore,the single-crystal structure analysis,elemental analysis,infrared,thermogravimetric,magnetic and fluorescence properties of the synthesized coordination polymers were characterized.In the third chapter,we synthesized three new coordination polymers constructed from monoacylhydrazidate molecules based on the in situ acylation reaction between 2,3-quinolinedicarboxylic acid and N2H4·H2O by the solvothermal self-assemblies synthesis method.Molecular formula:Mn(QLPTH)2(H2O)2(1),M(QLPTH)(H2O)2Cl(M = Mn(2)or Mg(3)).Among them,compound 1 is a mononuclear structure,2 and 3 are isomorphous binuclear structures,and the coordination units of the three compounds pass through intermolecular hydrogen bonds,respectively.And π…π stacking links coordination units into a three-dimensional supermolecular network structure.Compounds 1 and 3 have green emission and 2 has violet emission.In order to further understand the luminescence mechanism,quantum chemical calculations were carried out on both the ground and the excited states of compounds 1,2 and 3.The calculated results revealed that the luminescences of the three compounds are caused by the electron transfer between the ligands.At the same time,the magnetic properties of compounds 2 and 3 were studied.The results of temperature-variation magnetic susceptibility data fitting and Curie-Weiss fitting illustrated that there are weak antiferromagnetic interactions in the two compounds.In the fourth chapter,we synthesized three new diacylhydrazidate-coordination polymers as well as one acylhydrazide molecule based on the in situ acylation reaction between 4,4’-oxydiphthalic acid or 4,4’-benzophenone tetracarboxylic acid with N2H4·H2O by the solvothermal self-assemblies synthesis method.Molecular formula:M(ODPTH)(H2O)3(M = Fe(4),Co(5),Ni(6)),[DPTH](7).The result of the single crystal structure shows that the three compounds are isomorphous.Among them,the coordination polymers 4-6 have one-dimensional double-stranded structures,all of which were constructed by 4,4’-oxydiphthaloylhydrazone(ODPTH).And then the three-dimensional supramolecular network structures were further created through the hydrogen bonds between chains andπ…π stacking action.The results of varying temperature magnetic susceptibility and the fitted of the Curie-Weiss law indicated that there are antiferromagnetic coupling effects among metal ions in this three compounds.In the fifth chapter,we synthesized two novel monoacylhydrazidate-coordination polymers and one acylhydrazide molecule based on the in situ acylation reaction between 5,6-benzimidazole dicarboxylic acid with N2H4·H2O by the solvothermal self-assemblies synthesis method.Moreover,we also synthesized four coordination complexes by the solvothermal self-assemblies between metal salts and 2-propyl-5,6-imidazole dicarboxylic acid(H4pimdc).Molecular Formula:[M(BMPTH)](H2bpy)0.5(M =Zn(8)or Co(9)),[BMPTH](10),M(H2pimdc)2(phen)(M = Co(11),Fe(12),Ni(13),Mn(14)).The single-crystal structure analysis shows that compounds 8 and 9 have three dimensional structures.H4pimdc does not undergo acylation and directly coordinates with metal ions.The magnetic properties study found that compound 9 had a spin-flop magnetic phase transition at 2-3 K and compounds 11 and 12 had antiferromagnetic interactions,and the magnetic susceptibility of compound 11 exhibited magnetic relaxation,indicating that there existed field induced single ion magnet behavior in compound 11.In the sixth chapter,we also synthesized one coordination complex based on the in situ cyclizative condensation reaction between o-phenylenediamine(o-phen)and oxalic acid(H2ox)by the solvothermal self-assemblies synthesis method.Molecular Formula:[Co(H2bbim)3]Cl2(H2O)2(15).The single-crystal structure analysis shows that compound 15 is a mononuclear coordination complex constructed from 2,2’-bibenzimidazole,and the coordination unit is further built into a three-dimensional supramolecular structure by hydrogen bonding between molecules.The dc magnetic susceptibility results show that there are antiferromagnetic interactions in the compound 15.Interestingly,the results of alternating temperature magnetic susceptibility exhibited magnetic relaxation phenomena,indicating that compound 15 has the property of field-induced single-ion magnets.The work during the Master’s degree was summarized and analyzed.The synthesis conditions of in situ acylation reaction and in situ cyclization condensation reaction and the preliminary relationship between the structure and properties of the coordination polymer materials were discussed.It provided an effective strategy for semi directional and directional synthetic functional coordination polymers.