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机构地区:[1]武汉大学化学与分子科学学院,湖北武汉430072
出 处:《发光学报》2003年第5期485-488,共4页Chinese Journal of Luminescence
基 金:国家自然科学基金资助项目(29971024)
摘 要:通过将流变相反应制得的苯甲酸锌Zn(C6H5CO2)2热解得到了具有无限延伸三维结构的超分子化合物四核苯甲酸锌Zn4O(C6H5CO2)6,并对其发光性质、发光机理及其与结构的关系进行了初步探讨。X射线单晶衍射测定结果表明该化合物属于单斜晶系,Ia 3d空间群,它具有很大的晶胞,晶胞参数为:a=41 0063(18) ,V=68953(5) 3,Z=48。该化合物在紫外或可见光的激发下(λex=330,460nm),可以发出类似于Zn4O(CH3CO2)6的较强荧光(λem=530nm),该发射带属于pπ (L,O2-)→4sσ(Zn2+)的配体 金属的电荷迁移跃迁发射(LMCT)。分子中4个Zn原子与中心O原子及配体的相互作用,尤其是Zn4O四面体、OZn4O12八面体结构的存在对该发射带的产生起了重要作用,决定了该化合物的发光性质。Polynuclear complexes with d10 metals, which often possess unique structures and properties, have drawn a lot of attention. For the preparation of tetranuclear zinc carboxylate, four methods have been used: (a) by the reaction between zinc oxide and the carboxylic acid in the appropriate proportion; (b) by the thermal decomposition of the neutral carboxylate Zn(RCO2)2; (c) by the reaction of zinc oxide with the neutral carboxylate and (d) by the hydrolysis of the neutral zinc carboxylate. In the present work, a tetranuclear zinc benzoate Zn4O(C6H5CO2)6 was synthesized by the thermal decomposition of zinc benzoate Zn(C6H5CO2)2 in an inert atmosphere. Its electronic absorption, infrared, excitation and emission spectra were investigated. The nature of luminescence and the relationship between structure and luminescent property were discussed. Structure refinement showed that Zn4O(C6H5CO2)6 has a cubic structure, space group Ia3d, with great crystal cell: a=410063(18)?, V=68953(5)?3,Z=48. In the crystal all benzoates coordinate with zinc atoms in a bidentate bridging mode, four zinc atoms form a regular tetrahedron. Each Zn4O(C6H5CO2)6 molecule is in an octahedron geometry and every four adjacent molecules constitute a slightly distorted tetrahedron. The complex Zn4O(C6H5CO2)6 possesses an infinitely extended threedimensional supramolecular structure. It emits a green luminescence under the excitation of UV/blue light in solution or in the solid state. Its excitation and emission bands at 290~330 and 370nm are attributed to the ligandcentered transition. The excitation bands at about 460nm and the emission band at about 530nm are assigned to the LMCT (ligand to metal charge transfer) transition of pπ* (L,O2-)-4sσ(Zn2+). The luminescent property has relation with its particular structure. In the nature of its excitation and emission spectra,
关 键 词:四核配合物 发光机理 电荷迁移跃迁发射 晶体结构 测定 轨道能量 谱带偏移 四核苯甲酸锌配合物
分 类 号:TN383.1[电子电信—物理电子学] O482.31[理学—固体物理]
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