吡啶-2,6-二甲酸铅配位聚合物的绿色合成与表征

Green Synthesis and Characterization of Lead(Ⅱ)Coordination Polymer of Pyridine-2,6-Dicarboxylate

以吡啶-2,6-二甲酸(H_(2)pda)和乙酸铅为原料,用室温固相法合成配位聚合物[Pb(μ-pda)]_(n)(1),用元素分析、X射线粉末衍射和单晶衍射、红外光谱对聚合物1的组成和结构进行了表征,并研究其热稳定性和荧光性能。单晶结构显示,1属于单斜晶系,P2_(1)/n空间群,晶胞参数为a=0.98084(11)nm,b=0.55473(7)nm,c=1.43362(16)nm,β=105.093(3)°。1的分子结构由2个Pb^(2+)和2个pda^(2-)构成,含2个[Pb(μ-pda)]单元,每个Pb^(2+)与来自pda^(2-)的6个氧原子和1个氮原子配位,形成了七配位的单帽三角棱柱构型。热稳定性研究表明,1在氮气气氛中的热分解反应包括配位聚合物骨架的坍塌和配体的氧化分解,热解残余物为PbO。荧光性能测试结果表明,该配位聚合物具有荧光性,其荧光可能来自配体内部的π^(*)→π电荷跃迁。

The coordination polymer[Pb(μ-pda)]_(n)(1)was synthesized with pyridine-2,6-dicarboxylic acid(H_(2)pda)and lead acetate as raw materials by room temperature solid state reaction.The composition and structure of 1 were characterized by elemental analysis,X-ray powder diffraction,X-ray single crystal diffraction and infrared spectroscopy.Its thermal stability and fluorescence properties were also studied.The single crystal structure shows that 1 belongs to monoclinic system with space group P2_(1)/n,and the cell parameters are a=0.98084(11)nm,b=0.55473(7)nm,c=1.43362(16)nm andβ=105.093(3)°.The molecular structure of 1 is composed of two Pb^(2+) and two pda^(2-).It contains two[Pb(μ-pda)]units,each Pb^(2+) center is coordinated with six oxygen atoms and one nitrogen atom from pda^(2-) to form a seven coordinated single-cap triangular prism configuration.The thermal stability study shows that the thermal decomposition reaction of 1 in nitrogen atmosphere include the collapse of complex framework and the oxidative decomposition of ligand,and the final residue is PbO.The fluorescence property of 1 indicates that the coordination polymer has fluorescence,which may come from the fluorescence inside the ligandπ^(*)→πcharge transition.