1,3-二(4-吡啶基)-丙烷与邻苯二甲酸构筑的过渡金属配合物的合成、结构和荧光性质

以1,3-二(4-吡啶基)-丙烷(bpp)和邻苯二甲酸(1,2-H2bdc)为配体,通过水热法合成了过渡金属配合物M2(1,2-bdc)2(bpp)2·2H2OM=Co(1),Ni(2)]和Cd(1,2-bdc)(bpp)·H2O(3).配合物1和2属单斜晶系P21空间群,具有相似的三维骨架结构.配合物中存在2种配位环境相似的金属中心,每个金属中心采取六配位的畸变八面体构型,与来自2个1,2-bdc配体的3个氧原子和2个bpp配体的2个氮原子以及1个水分子配位.1,2-bdc配体采取单齿/双齿螯合的配位模式将金属离子连接成M1-(1,2-bdc)-M2右手螺旋链.bpp配体采取Trans-Gauche(TG)构型,连接相邻的金属离子形成M1-(bpp)-M1链和M2-(bpp)-M2链.这3种链交织在一起构筑成具有{65.8}拓扑的三维结构.配合物3属单斜晶系P21/c空间群,具有单节点的双层二维结构.Cd(Ⅱ)离子采取七配位的畸变五角双锥体构型,与来自2个1,2-bdc配体的4个氧原子,2个bpp配体的2个氮原子和1个水分子配位.1,2-bdc配体采取双齿螯合/双齿螯合的配位模式将Cd(Ⅱ)离子连接成Cd-(1,2-bdc)-Cd链.bpp配体采取TG构型,连接相邻的Cd(Ⅱ)离子,形成Cd-(bpp)-Cd链.这2种链通过共享Cd(Ⅱ)离子交错排列构筑成二维结构.配合物3显示出强的荧光,最大发射位于408 nm处,对应于配体的π*-π跃迁.不同有机小分子对配合物3的荧光强度有不同程度的影响,苯胺对其有显著的猝灭作用,基于荧光猝灭机理,配合物3可用于选择性检测苯胺分子.

Synthesis,Structure and Luminescence Property of Transition Metal Complexes with 1,3-Di(4-pyridyl)-propane and 1,2-Benzenedicarboxylic Acid

Taking 1,3-di(4-pyridyl)-propane(bpp) and 1,2-benzenedicarboxylic acid(1,2-H2bdc) as ligands,three new transition metal complexes,M2(1,2-bdc)2(bpp)2·2H2OM(Ⅱ)=Co(1),Ni(2)] and Cd(1,2-bdc)(bpp)·H2O(3),were obtained.Complexes 1 and 2 crystallize in monoclinic crystal system with space group P21 and show 3D structures with 6558 topology.There are two M(Ⅱ) centers with the similar coordination environments in complexes 1 and 2.Each M(Ⅱ) center is six-coordinated to three oxygen atoms from two 1,2-bdc ligands,two nitrogen atoms from bpp ligands and one water molecule in a distorted octahedral arrangement.The 1,2-bdc ligand adopts monodentate bridging/bidentate chelating mode to link two metal centers to form M1-(bpp)-M1 right-handed-helical chain.The bpp ligand adopts Trans-Gauche(TG) conformation and connects adjacent M(Ⅱ) centers to form M1-(bpp)-M1 and M2-(bpp)-M2 chains.These three kinds of chains are woven together to form a 3D framework.Complex 3 crystallizes in monoclinic crystal system with space group P21/c and shows a 2D structure.The Cd(Ⅱ) is in distorted pentagonal bipyramidal polyhedron with four oxygen atoms of two 1,2-bdc ligands,two nitrogen atoms of bpp ligand and one water molecule.The 1,2-bdc ligand adopts bi(bidentate chelating) mode to link Cd(Ⅱ) centers to form Cd-(1,2-bdc)-Cd chain.The bpp ligand adopts TG conformation and connects Cd(Ⅱ) centers to form Cd-(bpp)-Cd chain.The two kinds of chains with shared Cd(Ⅱ) are alternately arranged to form a 2D structure.Complex 3 shows strong ligand-based fluorescence with maximum emission at 408 nm,which is attributed to π*-π transition of the ligands.Different organic small molecules have different effects on the fluorescence intensity of complex 3,and aniline has a significant quenching effect,thus complex 3 can be used for the selective detection of aniline through fluorescence quenching mechanism.