紫光化合物[Cd(bpdc)(phen)_2(H_2O)]·6H_2O的合成、结构及荧光光谱研究

A Purple-Emitting Luminescence Complex[Cd(bpdc)(phen)_2(H_2O)]·6H_2O:Synthesis,Structure and Spectral Properties

以2,4′-联苯二甲酸(H2bpdc)和1,10-邻菲罗啉(phen)为配体,采用水热法合成一例三维超分子网状镉(Ⅱ)配合物[Cd(bpdc)(phen)2(H2O)]·6H2O(1)。通过单晶X射线衍射分析,元素分析和红外光谱分析表征化合物1的结构。单晶X射线衍射分析结果表明,化合物1属于三斜晶系,P1空间群,中心金属Cd(Ⅱ)离子呈现六配位扭曲八面体构型,通过两种氢键作用和π—π堆积作用形成三维超分子结构。同时,对化合物1进行固态/溶液以及不同温度下的荧光性能测试。以350nm为激发波长进行激发,298K固态时,化合物1在390nm处有强发射峰,呈现紫色荧光;77K固态时,化合物1的荧光光谱具有两个发射谱带,分别位于380和520nm处,是因为在低温时化合物1表现出精细结构。298K时,化合物1在DMSO溶液和CH3OH溶液中分别在380和375nm有最大发射,相对于固态最大发射波长发生蓝移,呈现紫色荧光。这均是基于中心金属微扰配体中心的π*→π跃迁发射。研究了化合物1固态和溶液的荧光寿命,化合物1荧光衰减过程包含双组分。298K条件下,化合物1在DMSO溶液中的寿命(τ1=1.73μs和τ2=14.07μs)比CH3OH溶液中的荧光寿命(τ1=1.21μs和τ2=12.44μs)长。此外,77K固态时的荧光寿命(τ1=1.96μs和τ2=16.11μs)长于298K的固态荧光寿命(τ1=1.20μs和τ2=11.34μs),这是因为低温条件下降低分子内部的非辐射跃迁,从而延长固态荧光寿命。

A supramolecular Cd（Ⅱ） complex[Cd（bpdc）（phen）2 （H2O）]？6H2O （1） was synthesized with 2 ,4’-biphenyldicar-boxylic acid （H2 bpdc） and 1 ,10-phenanthroline （phen） under hydrothermal conditions and characterized by single-crystal X-ray diffraction elemental analysis ,and IR spectrum .Single-crystal X-ray analysis reveals complex 1 crystalizes in the triclinic P 1 space group ,the metal center Cd（Ⅱ ） ion is six-coordinated and exhibits a distorted octahedron geometry arrangement .3D su-pramolecular structure could be formed taking into account two kinds of hydrogen bonds and π—π interactions .At the same time ,we discussed the luminescent properties of complex 1 in the solid-state as well as in the solvents at different temperatures . When excited at 350 nm ,in the solid state at 298 K ,1 has purple luminescence with emission band at 390 nm ;in the solid state at 77 K ,1 displays two emission bands at 380 and 520 nm .Because the vibration structure is more defined at low temperature , at 298 K ,1 also has purple luminescence in DMSO and CH3OH solutions with emission bands at 380 and 375 nm ,which are blue-shifted compared with solid-state maximum emission band .These all can be attribute to theπ＊ →π transition based on the coordinate ligands .The fluorescence decay curves of complex 1 indicate that the processes of decay consist of two components . At 298 K ,the lifetime of 1 is longer in DMSO solution （τ1 =1.73μs andτ2 =14.07μs） than that in CH3 OH solution （τ1 =1.21μs and τ2 =12.44 μs） .Moreover ,the lifetime of 1 is longer at 77 K （τ1 =1.96 μs and τ2 = 16.11 μs） than that at 298 K in the solid state （τ1 =1.20μs andτ2 =11.34 μs） .The results might be caused by the increase in radiative rate and decrease in non-ra-diative rate at low temperature .