The Research On Synthesis,Structures And Properties Of Carboxylic Acid/Nitrogen Heterocyclic Coordination Polymers

In recent years,coordination polymers as a kind of compound by the self-assembly of metal ions and organic ligands,have attracted the scientists’interests,not only for their charming crystal structures and variety of topologies,but also because of their potential applications on luminescence,magnetism,catalysis and gas storage,etc.In this dissertation,different carboxylic acid/azacyclic organic ligands were selected and polyoxometalates（POMs）were used as inorganic ligands or template agents to self-assemble with metal ions.Through continuous improvement of reaction conditions,13 coordination polymers were obtained and characterized by infrared spectroscopy,X-ray single crystal diffraction,elemetal analysis,X-ray powder diffraction and thermogravimetric analysis.The magnetic and electrochemical properties of some complexes were measured by using a magnetic measurement system and an electrochemical workstation.1.Based on 1,4-naphthalenedicarboxylic acid（1,4-H₂ndc）ligand,two new CPs have been obtainedbysolvothermalandsolutionvolatilizationmethods,whichare[Mn₂（1,4-ndc）₂（OAc）]（C₅MIm）·0.5H₂O}_n（1）and{[Co₃（1,4-ndc）₄（H₂O）₄]（C₅MIm）₂·2H₂O}_n（2）.In compound 1,Mn（II）ions are bridged byμ₂-η¹:η¹ acetate radical and carboxyl groups of 1,4-ndc^2–ligands,froming a wave-like one-dimensional chain.The chains are further linked by theμ₄-η¹:η¹:η¹:η¹ 1,4-ndc^2-ligands,thus expanding into 3D structure.In compound 2,a linear[Co₃（H₂O）₂（CO₂）₄]SBU is fromed by the connection of syn,syn-μ₂-η¹:η¹ carboxyl groups and bridging water molecules,and then extend to a 3D network structure through the carboxyl groups bridging of 1,4-ndc^2-ligands withμ₄-η¹:η¹:η¹:η¹ andμ₂-η¹:η⁰:η¹:η⁰ coordination modes.Through topological analysis,compounds 1 and 2 can be simplified as lon and bcu topology,respectively.Magnetic tests show that both compounds exhibit antiferromagnetic behaviors with the best fit of the magnetic susceptibility data of 1 at 10-300 K:g=2.1 and J=-0.85 cm^-1.2.Based on 4’-（4-carboxyphenyl）-2,2’:6’,2’’-terpyridine（Hcptpy）ligand,four new CPs were obtained under the regulation of triazine:[CuCl（cptpy）·2H₂O]_n（3）,[Mn₂Cl₂（cptpy）₂（phdat）H₂O]_n（4）,[La（cptpy）₃]_n（5）,and[Pr（cptpy）₃]_n（6）.In compound 3,Cu（II）ions and cptpy^–ligands are alternately connected to form a 1D chain and further expand to 2D layer configuration byπ...πstacking interactions between chains.In compound 4,two kinds of 1D chains are formed through the connection of two different coordination modesμ₁-η¹:η¹ andμ₂-η²:η¹ cptpy^–ligands with Mn（II）ions,and the stacking structure of 3D is further formed by theπ...πstacking and hydrogen bonding interactions between cptpy^–and free triazine ligands.Compounds 5 and 6 are isomorphism,in which the La（III）/Pr（III）ions are alternately connected to the cptpy^–ligands to form a bow-shaped 1D chain and extend to 3D structure byπ...πstacking interaction.Electrochemical analysis shows that compound 4 has a good catalytic effect on H₂O₂ and NaNO₂.Magnetic analysis shows that compound 5 exhibits antiferromagnetic behavior.3.Based on 2,6-bis（1,2,4-triazol-1-yl）pyridine（btp）,1,4-bis（1-imidazolyl）benzene（bib）, 1,3,5-（1-Imidazolyl）benzene（tib）and 2,6-bis（1-imidazolyl）pyridine（bip）ligands,7 novel CPs were synthesizedwiththeparticipationofPOMs:[Co₂（btp）₄(W₁₀O₃₂)（H₂O）₂]_n（7）,[Cd₃（btp）(PW₁₂O₄₀)₂（H₂O）₆·6H₂O]_n（8）,[Ag₃（btp）₂(PMo₁₂O₄₀)·1.5H₂O]_n（9）,[Fe₂（btp）₃(SiW₁₂O₄₀)（H₂O）₆·3H₂O]_n（10）,[Cu（bip）₂(H₂PMo₁₂O₄₀)]_n（11）[Co₂（bib）₃(H₄W₁₂O₄₀)（H₂O）₂·7H₂O]_n（12）and[Zn₃（tib）₄(H₃ZnW₁₂O₄₀)₂（H₂O）₂·2H₂O]_n（13）.In compound 7,Co1 ions are bridged by btp ligands to form a 2D rhombic grid structure,which can be simplified as sql topology.While the Co2 ions expand to 3D network structure through the bridging of btp and W₁₀O₃₂^4-,which can be simplified as rob topology.Interestingly,the two configurations are interspersed with each other,and eventually form a rare 3D interpenetration structure.In compound 8,helical chains with opposite chirality exist simultaneously in three planes,and the 3D structure containing different sized cavities is further formed by staggered connection of helical chains,which can be simplified as a sqc type topology,and the PW₁₂O₄₀^3-are filled in the cavity by electrostatic interaction.In compound 9,the 2D zig-zag layered structure is constructed by the connection of two different coordination modes ligands with metal ions,and further expand to 3D network with the bridging of PMo₁₂O₄₀^3-.In compound 10,Fe（II）ions are bridged by btp ligands to form a 2D layered structure.Interestingly,in the layered structure,adjacent metal ions are connected end to end with the ligand to form a closed fan leaf shape.Its structure can be simplified as a rare 2-nodal（2,3）-connected hxl topology,and SiW₁₂O₄₀^4-are filled into 2D layers.Compound 11exhibits two-coordinated mononuclear unit and further extend to a 1D chain byπ...πstacking interaction.In compound 12,2D layer is fabricated by the connection between metal ions and H₄W₁₂O₄₀^4-,and further extend to a 3D network structure by the bridging of bib ligands,which can be simplified as two types of topology from different perspectives:one is a sqc type topology similar to a multi-layered graphene structure,and the other is a very rare topological type,whose point symbol is{3³³.4⁵⁷.6}.In compound 13,Two crystallographic independent Zn（II）ions form two different 2D layers（type A and type B）by bridging tib and H₃ZnW₁₂O₄₀^3-,respectively.These 2D layers are packed on each other by means of BAABAAB pattern.Compounds 9 and 11 exhibit good catalytic activity for H₂O₂ and NaNO₂,respectively.