Coordination Polymers Based On5-carboxy-1-(4-carboxy-benzyl)-2-oxidopyridinium: Syntheses And Structures

Seven new coordination polymers which have never been reported, namely,[Zn（L）（biim-4）]·3H₂O （1）,[Co（L）（biim-4）_0.5]（2）,[Zn（L）（btpy）]·1.75H₂O·0.25EtOH（3）,[Co（L）（btpy）]（4）,[Cd₃（L）2（OH）2（btb）（H₂O）2]（5）, Cd（L）（phen）（H₂O）]·H₂O （6）,and [Pb（L）（H₂O）_0.5]（7）, where H₂L=5-carboxy-1-（4-carboxybenzyl）-2-oxidopyridinium, biim-4=1,1’-（1,4-butanediyl）bis（imidazole）, btb=1,2-bis（1,2,4-triazole-1-yl）ethane, phen=1,10-phenathroline, and btpy=2-（4-（4’-tert-butylphenyl）-6-（pyrindin-2-yl）pyri-din-2-yl） pyridine, have been compounded in the hydrothermalconditions. Compound1is an unusual2Dâ†'2D interdigitated double layer formedby π···π interactions. Compounds2shows a3D6-connected framework with the（43·611·8） topology. Compound3and6are isomorphous and exhibit the same1Dchains structure, which are extended to a2D supramolecular layer byhydrogen-bonding interactions and π···π interactions, respectively. Compound4shows a0D dimeric molecular structure, which is further linked by intermolecularhydrogen-bonding interactions to form a2D supramolecular layer. Compound5displays a2D wave-like layer, which is extended into different3D supramolecularframework by intermolecular hydrogen-bonding interactions. Compound7exhibits a2D undulated （4,4） network. The structural differences among these compounds showthat neutral ligands and central metals play crucial important roles in producing novelframeworks and topologies of the coordination polymers. The seven complexes werestructurally characterized by X-ray diffraction analyses and further characterized bythermogravimetric （TG） analyses, elemental analyses, powder X-ray diffraction（PXRD） and infrared spectra （IR）.