Synthesis And Properties Of Functional Coordination Polymers Controlled By Ligand

Coordination Polymers(CPs),are a new class of materials,which is composed of metal ions(clusters)and organic bridging ligands through coordination covalent self-assembly.The specific component determines the materials have high frame adjustable and diverse structure and other characteristics,making it show distinctive application prospects in the selective catalysis,chiral separation,fluorescence,magnetic,sensor,drug delivery,gas adsorption and separation,which has attracted more and more attention to the frame material workers.However,because of being influenced by many factors which determine the synthetic action sites and functional effects of self-assembly process,it is still a hot spot in the field of research on how to synthesize the framework materials with specific structure and function,and to explore the relationship between structure and property and to expand the application domain.In this paper,we choose a series of transition metal and three kinds of organic ligands to design and synthesis thirteen kinds of novel frame materials under solvothermal/hydrothermal conditions from the regulation of ligand,then characterized by X-ray single crystal diffraction,thermal gravimetric(TGA),X-ray powder diffraction(PXRD),magnetic,fluorescence and gas adsorption.This paper focuses on the analysis of the effect of organic ligands on the structure of the framework and the influence of the functional groups on the structure and function.The main work of this paper is divided into the following three aspects:(1)Synthesis,structure and properties of MOFs based on the ligand of cyclotriphosphazene derivatives.Using three kinds of flexible six-membered ligand based on cyclotriphosphazene,hexakis(4-carboxylato-phenoxy)cyclotriphosphazene(H6L1),hexakis(3-carboxylato-phenoxy)cyclotriphosphazene(H6L2),hexakis(4-tetrazol-phenoxy)cyclotriphosphazene(H6L3)and the auxiliary ligand of 4,4'-bipyridine with a series of transition metal under hydrothermal conditions,we obtained eight novel coordination polymers:?[Zn11O(L1)4(H2O)6]·xGuest}n(1),[Mn6(L1)2(H2O)5]n(2),[Ni3(Ll)(4,4'-bpy)(H2O)2]n(3),{[Cd3(Ll)(H20)5]}n(4),{[Cd4(L2)2(H2O)8]?n(5),{[Cd2(L3)2(H2O)2]·(H20)}n(6),[Cu6(L1)2(H2O)6]n(7),[Cu3(Ll)(4,4'-bpy)2(H20)6]n(8).Compound 1 exhibits a novel anionic metal-organic framework based on an octa-nuclear zinc cluster,showing the variable luminescent properties controlled by different guest cations,especially for the magnesium ions;compound 2 is a robust 3D homochiral porous MOF,constructed based on 1D helical Mn?-chains,which leaves 1D helical channel in the structure and exhibits specific responsive behavior to ketone molecules;compound 3 exhibits 2D interpenetrate structure with magnetic properties;compounds 4,5,6 have been successfully synthesized under solvothermal conditions,which are based on cadmium ions and three kinds of ligands,respectively.However,Variable metal-nodes(trinuclear,binuclear and tetranuclear for 4,5 and 6,respectively)had been stabilized in the final structures,which are related to the coordination ability of corresponding ligands.In addition,the luminescent properties of these three complexes were studied,and the effect of ligand on the synthesis of coordination polymers was discussed;Although 7 and 8 are 3D framework materials with 1D channels,the structure of 8 make change through introduction of the auxiliary ligand of 4,4'-bipyridine.(2)Template controlled synthesis and properties of cluster-based porous coordination polymers.Two distinct template mediated coordination polymers,[Co3(ina)4(N3)2(CH3OH)2](9)with tri-nuclear nodes and[Co8(OH)(ina)8(N3)8.X](10)with dual tetra-nuclear cobalt nodes,have been synthesized under hydrothermal conditions by utilizing the template agent of pentaerythritol.Compound 9 shows a 2D layer comprised of linear tri-nuclear Co?clusters,in which the central cobalt ion is inter-linked with two terminal ones via mixed bridges as syn-syn carboxylates and end-on azide ions.In contrast,compound 10 exhibits a three-dimensional framework based on two kinds of six-connected tetra-nuclear cobalt clusters:square-planar node and cuboidal node.Both 9 and 10 might exhibit spin-canted magnetism.In addition,the activated sample of 10 exhibits the sorption ability of H2 and CO2 molecules.(3)Synthesis,structure and properties of MOFs based on mixed ligand.Three new MOFs with a novel bifunctional ligand 6-(1H-tetrazol-5-yl)-2-naphthoic acid(L4),namely,Zn(L4)]n(11),[Cd(L4)(H2O)]n(12)and[Cu4.5(L4)5(H2O)]n(13)have been synthesized under solvothermal conditions and structurally characterized,which reveal that the three constructed CPs exhibit three dimensional structures.These CPs consist of a 1D Zn-tetrazole chain,a 2D Cd-tetrazole and a novel hepta-nuclear copper cluster with 1D channel structures,respectively.The result of gas adsorption of 13 shows that it is a mesoporous material.In addition,a gradient in the fluorescence spectra of the free ligand,11 and 12 was present at room temperature.Through variable-temperature luminescent and careful quantum calculations,the blue-shift of the peak from the ligand and 11 and 12 is assigned to the different configurations and conjugation degrees of the ligand,which are caused by the different coordination environments of the metal ions.All the obtained results are very helpful to understand the fluorescent mechanism of CPs,and to some extent guide,the rational synthesis of functional materials in the future.