卤离子导向合成配位聚合物[Hg_2X_4(ppt)]_n(X=I和Br;ppt=1-(4-吡啶基)-吡啶铵-4-硫醇盐)及不同的一维链状结构和三阶非线性光学响应  

Halide-Directed Synthesis of Coordination Polymers [Hg_2X_4(ppt)]_n (X=I and Br, ppt=1-(4-Pyridyl)-pyridinium-4-thiolate) with Different One-Dimensional Chain Structures and Third-Order Nonlinear Optical Properties

作　　者：倪春燕[1,2] 陈阳[1] 李端秀[1] 任志刚[1] 李红喜[1] 孙真荣[3] 郎建平[1,2] 

机构地区：[1]苏州大学材料与化学化工学部,苏州215123 [2]中国科学院上海有机化学研究所金属有机化学国家重点实验室,上海200032 [3]华东师范大学物理系,上海200062

出　　处：《化学学报》2013年第6期906-912,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(No.21171124);上海有机化学研究所金属有机化学重点实验室开放基金(No.201201006)资助~~

摘　　要：通过HgX2(X=I,Br)与4,4'-二吡啶基二硫化物(dpds)在乙腈中的溶剂热反应,得到二个含1-(4-吡啶基)-吡啶铵-4-硫醇盐(ppt)的一维配位聚合物:[Hg2I4(ppt)]n(1)和[Hg2Br4(ppt)]n(2).在化合物1和2结构中ppt配体是由dpds在溶剂热反应条件下通过dpds的S—S键和S—C键切断然后进行重排在原位形成的.化合物1具有非中心对称的一维Z字型链状结构,化合物2则具有中心对称的一维Z字型链状结构.用飞秒简并四波混频法测定了1和2溶液的三阶非线性光学性质,化合物1具有较强的非线性光学响应,而化合物2却没有非线性光学响应,这种性质的差异可能由于碘离子是较溴离子更好的电子授体,化合物1有较小的HOMO-LUMO能级,更易发生电子在体系间跃迁,更有效使用三线激发态吸收.Solvothermal reactions of HgX2 （X=I, Br） with 4,4＇-dipyridyl disulfide （dpds） in acetonitrile gave rise to two one-dimensional polymers [Hg2X4（ppt）]n [ppt=1-（4-pyridyl）-pyridinium-4-thiolate; X=I （1）, Br （2）]. In the structures of 1 and 2, the ppt ligand was in situ generated from the Hg（II）-engaged cleavage of both S—S and S—C bonds of dpds and the subsequent rearrangement reactions under solvothermal conditions. Although compounds 1 and 2 have similar chemical formula, 1 crystallizes in the orthorhombic space group Ima2 and holds a 1D non-centrosymmetric zigzag chain while 2 crystallizes in the orthorhombic space group Pnma and has a 1D centrosymmetric zigzag chain. Such a difference in structural symmetry between 1 and 2 may be due to the fact that the radius of iodide is larger than that of bromide. The third-order nonlinear optical （NLO） behaviours of 1 and 2 in DMF were investigated by using femtosecond degenerate four-wave mixing technique. Compound 1 exhibited relatively strong NLO responses while compound 2 showed nothing. Such a remarkable difference in the NLO property may be due to the fact that iodide is a better electron donor than bromide, which allows more efficient spin-orbital coupling, and facilitates intersystem crossing and more efficient usage of triplet excited state absorption.

关 键 词：卤离子导向 配位聚合物 溶解热合成 结构 非线性光学 

分 类 号：O634[理学—高分子化学]