Three Zinc(Ⅱ) Complexes Based on 2-Carboxylic Acid-4-nitropyridine-1-oxide: Synthesis,Crystal Structure,and Fluorescence Properties

Three new metal-organic complexes, namely [Zn(POA)2(H2O)2](1), [Zn(POA)2(H2O)2]·2H2O(2) and [Zn(POA)2]n(3), have been synthesized by organic ligand 2-carboxylic acid-4-nitropyridine-1-oxide(POA) and zinc(Ⅱ) ions. The structures of complexes 1~3 are characterized by single-crystal X-ray analysis, XRD powder diffraction analysis, infrared spectroscopy and thermal stability analysis method. Complex 1 belongs to monoclinic system, space group C2/c with a = 22.8215(15), b = 7.5613(16), c = 10.048(3) ?, β = 109.47°, V = 1634.7(6) ?~3, Z = 4, F(000) = 944, Dc = 1.900 g/cm^3, C(12)H(10)N4O(12)Zn, Mr = 467.61 and μ = 1.584 mm^-1. The whole molecule presents "V" shape. Complex 2 is a centrosymmetric structure in triclinic system with space group P1: a = 7.4728(5), b = 7.6825(6), c = 8.5184(6) ?, α = 65.975(2), β = 79.87(2), γ = 89.855(2)°, V = 4384.1(5) ?~3, Z = 1, F(000) = 256, Dc = 1.908 g/cm^3, C(12)H(14)N4O(14)Zn, Mr = 503.64 and μ = 1.492 mm^-1. Complex 3 is a one-dimensional chain structure belonging to monoclinic system and space group P21/c with a = 4.9456(6), b = 12.5322(14), c = 11.2514(13) ?, β = 97.313(11)°, V = 6916.8(14) ?~3, Z = 2, F(000) = 432, Dc = 2.072 g/cm^3, C(12)H6N4O(10)Zn, Mr = 431.58, and μ = 1.852 mm^-1. In three complexes, six oxygen atoms from the surrounding coordination atoms form a ZnO6 distorted octahedral coordination geometry around the zinc ions. Meanwhile, fluorescent properties of the three complexes were investigated at room temperature. The fluorescence spectroscopic analysis demonstrated that the ligand POA shows red-shift after coordinating with the zinc(Ⅱ) ions.     

由醋酸根桥连构筑的零维六核镉(Ⅱ)格子型配合物和一维锌(Ⅱ)配位聚合物的合成、晶体结构及荧光性质

采用普通溶液法合成了配合物[Cd_6(Tppahz)_2(Ac)_2(H_2O)_6]5H_2O (1)和{[Zn_(1.5)(Tppahz)_(0.5)](Ac)_2}_n(2)(Tppahz=N,N′-二(吡啶-2′-甲缩)-2,6-吡啶二甲酰肼),并通过X射线单晶衍射分析、X射线粉末衍射分析、红外光谱分析和热重分析等对配合物的结构进行了测定。结果分析表明:配合物1是格子型结构,三斜晶系,■空间群,Cd(Ⅱ)离子与周围原子采用N_2O_5,N_3O_4两种不同的配位类型,形成扭曲的五角双锥构型;配位聚合物2是一维链状结构,单斜晶系,C2/c空间群,Zn(Ⅱ)离子与周围原子采用N_3O_2,N_2O_3两种不同的配位类型,形成畸变的四角锥配位构型。配位聚合物2通过π-π堆积作用形成了三维超分子结构。在室温下研究了2个配合物的荧光性质。荧光分析表明,配体Tppahz与d~(10)过渡金属离子配位后其荧光发生了红移。