在4,4’-联吡啶的两端引入芳香羧酸合成得到一种两性离子型紫精衍生物配体-二氯化-1,1’-二(4-羧基-苯亚甲基)-4,4’-联吡啶(H2BpybcCl2),作为一种多功能配体,紫精羧酸既具有紫精特殊的功能团,又含有羧基配位基团,因此逐渐成为构建金属-有机框架的一种理想配体.紫精羧酸与硫氰化铜形成的配位聚合物还未见报道.采用溶液扩散法将H2BpybcCl2配体与Cu2+离子和SCN-离子组装得到一个新颖紫精羧酸铜的配合物:［Cu(SCN)2(Bpybc)］(Ⅰ),并通过X-射线单晶衍射、XRD、元素分析、红外光谱(FTIR)、热重(TGA)分析、液态荧光光谱、UV-Vis DRS光谱等手段对其结构及光谱学性质进行了研究.单晶结构分析显示化合物Ⅰ属单斜晶系,C2/c空间群,晶体数据为:a=19.508(4) ,b=9.474(2) ,c=16.963(3) ,α=90°,β=124.92(3)°,γ=90°.在化合物Ⅰ的结构中,两个SCN-离子与Cu2+离子配位组成结构单元［Cu(SCN)2］,梯形的配体Bpybc桥连结构单元［Cu(SCN)2］ 沿着［203］方向形成一维“之”字链.这些链之间通过吡啶环和苯环的π—π作用堆积,拓展为三维超分子网络.固体紫外-可见漫反射光谱出现Bpybc配体π—π*跃迁吸收峰和Cu2+离子d→d跃迁吸收峰.液态荧光光谱测试显示化合物Ⅰ水溶液在360 nm光激发下,在533 nm处出现了强的蓝色荧光,该发射带是由紫精羧酸配体分子内电荷转移引起的.

A zwitterionic viologen derivative ligand,1,1’-bis(4-carboxybenzyl) -4,4’-bipyridinium dichloride(H2BpybcCl2) as a multifunctional ligand,has been synthesized incorporating a 4,4’-bipyridine core with two carboxylate groups as a building block,specifically designed for the rational construction of metal-organic frameworks.H2BpybcCl2 ligand is a multifunctional ligand that contains viologen’s specific functions and carboxylate coordination groups.The coordination polymers of viologen carboxylate with copper thiocyanate are not reported to date.A novel copper coordination polymer,［Cu(SCN)2(Bpybc)］(Ⅰ) was by solution diffusion method and characterized by single-crystal X-ray diffraction,XRD,elemental analyses,IR spectroscopy,UV-Vis DRS,TG analysis and liquid-state luminescent properties.Compound Ⅰ crystallized in the monoclinic system with C2/c space group.Crystal data for complex Ⅰ is as follow:a=19.508(4) ,b=9.474(2) ,c=16.963(3) ,α=90°,β=124.92(3)°,γ=90°.Two SCN- anions were coordinated to the Cu2+ cation forming a ［Cu(SCN)2］ unit.Complex Ⅰ was built up by ［Cu(SCN)2］ units bridged sequentially by ladder-shaped Bpybc ligands to form one-dimensional zigzag chains running along the ［203］ direction.The chains were held together by π—π interaction between the pyridine rings and phenyl rings,thus yielding a 3-D extended supramolecular network.The UV-Visible absorption spectra show the absorption bands of π—π* transitions of Bpybc ligands and d→d transition of Cu2+.The liquid-state luminescent property of compound Ⅰ was investigated at room temperature.Attractively,the complex exhibits strong blue emission peak at 533 nm(λEx=360 nm) that can be assigned to intraligand transition of Bpybc ligand when it was excited at 360 nm.