| The rational design and synthesis of metal-organic coordination polymers with novel structures or desired functions are one of the most attractive fields in current coordination chemistry and crystal engineering.The aim of this thesis is to synthesize novel metal-organic coordination polymers which may exhibit well magnetic/photoluminescence properties or higher free void volume,on the basis of azoxybenzene-tetracarboxylic acid ligand,diverse N-donor ligands and transition metal salts by changing reaction condition,to further explore the principle of self-assembley as well as the relationships between structures and properties.In this thesis,we choose 3,3',5,5'-azoxybenzene-tetracarboxylic acid(H4aobtc)to react with different N-donor ligands in the presence of different metal ions.By trial and error,we successfully design and synthesize ten novel coordination frameworks.In addtion,their structures were characterized by elemental analyses,ICP analyses,IR spectra,single-crystal X-ray diffraction analyses and X-ray powder diffraction(PXRD),while the thermal stabilities(TG),magnetic and fluorescent properties of these compounds have also been studied.1.Two novel coordination compounds with highly connected frameworks based on polynuclear metal clusters as secondary building units have been hydrothermally synthesized by self-assembly of H4aobtc ligand(3,3',5,5'-azoxybenzenetetracarboxylic acid)and bpy ligand(4,4'-bipyridine)in the presence of transition metal salts,that are,[Co7(aobtc)3(bpy)2(?3-OH)2(?2-OH2)2(H20)4]·4H20(1)[Ni5(aobtc)2(bpy)2(?3-OH)2(H20)6]·4H20(2)Compound 1 is a 3D(4,4,14)-connected self-penetrating framework with(46)2(45·6)(430·526·631·74)topology based on hexanuclear clusters as 14-connected nodes.To our knowledge,Compound 1 represents the highest connected self-penetrating topology presently known in the entangled system.Compound 2 displays a trinodal(4,4,10)-connected network with(46)(45·5)(410·518·612·75)topology based on tetranuclear clusters as 10-connected nodes.Further more,the octahedral cage built from metal clusters and aobtc ligands in 1 and 2 were occupied by the[M(bpy)2]2+(M = Co(1)and Ni(2))fragment.2.Based on such a finding,six coordination polymers with similar frameworks,but different pore volumes,have been synthesized by trying to change the transition metal salts or N-donor ligands,that are,[Zn3(aobtc)2]·H2bpy·H2O(3)[Zn3(aobtc)2]·H2bpp·H2O(4)[Cd3(aobtc)2]·[Me2NH2]·3H20(5)[Co3(aobtc)2]· Himi·H30·3H20(6)[Co3(aobtc)2]·H2bpp·H20(7)[Mn3(aobtc)2]·H2bpy · 2H20(8)Compounds 3-8 exhibit(4,8)-connected flu(fluorite CaF2 net,point symbol of(46)2(412·612·84))nets based on trinIclear clusters as 8-connected nodes,and these six CPs show similar structures but different pore volumes mainly associated with the change of the species of guest molecules.As calculated by PLATON analysis,the effective free volume of 3-8 are all over 30%of the crystal volume after all guest molecules are removed.Structural analyses of 1-8 demonstrate that increasing the metal nuclearity is a practical method to obtain highly connected coordination networks based on metal cluster as nodes.That provides some examples for further exploring the principle of compounds' self-assembley.3.Additionally,when hydrothermal reactions was replaced by solvothermal method,and with the absence of N-donor ligands,two 2D coordination polymers were obtained,that are,[Co3(Haobtc)2(H20)4]·11H20(9)[Mn3(Haobtc)2(DMA)2(H20)2]· 2H20(10)Compounds 9 and 10 are all 2D(3,6)-connected kgd(the Schlafli symbol:(43)2(46·66·83))network based on trinuclear clusters as 6-connected nodes.However,the 2D network stack in different fashion into a 3D supermolecular architecture,then the free volume in 9 and 10 estimated by PLATON is 40.8%and 6%(all guest water molecules are removed). |
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