三个低维Zn^Ⅱ-二膦酸配位聚合物的合成、结构及荧光性能研究

Syntheses, Structures and Fluorescent Properties of Three Low-Dimensional Zn~Ⅱ-Diphosphonate Coordination Polymers

通过引入第二配体2,2′-联吡啶（2,2′-bipyridine,bipy）,在水热条件下得到3个低维ZnⅡ-二膦酸配位聚合物：[Zn1.5（H2L）（bipy）（H2O）]·3H2O（1）,[Zn（H3L）（bipy）]2（2）,[Zn（H3L）（bipy）（H2O）]·H2O（3）（H5L=1-羟亚乙基-1,1-二膦酸,CH3C（OH）（PO3H2）2）。采用单晶X-射线衍射、粉末X-射线衍射（PXRD）、红外光谱（IR）、元素分析、热重（TG-DSC）等测试手段对产物的结构进行了表征。单晶X-射线衍射数据分析表明化合物1为一维梯形双链结构,结构中含有2个晶体学独立的锌离子,分别以四配位和六配位模式与配体连接。化合物2为O-P-O双桥连接三角双锥[ZnO3N2]而成的双核零维结构。化合物3为八面体[ZnO4N2]通过O-P-O单桥连接而成的一维链状结构。氢键和π-π堆积作用进一步将3个低维ZnⅡ-二膦酸化合物扩展为三维超分子。对化合物1~3进行荧光性能的研究,测试结果表明,3个化合物均发射出强度远大于配体bipy的荧光发射峰（λem=374nm（1）、388nm（2）、387nm（3）,λex=252nm）,该峰来源于第二配体bipy（λem=391nm,λex=252nm）分子内部的π＊-π电荷转移。电化学测试结果显示3个化合物均表现出一步单电子氧化还原过程,与自由配体相比给电子能力增强,未来可作为空穴传输材料在光电领域得到应用。

By introducing the second organic ligand 2,2′-bipy（bipy）, three low-dimensional examples of Zn（Ⅱ）-diphosphonate coordination polymers based on 1-hydroxyethylidenediphosphonic acid（H5L=CH3C（OH）（PO3H2）2）,[Zn1.5（H2L）（bipy）（H2O）]·3H2O（1）, [Zn（H3L）（bipy）]2（2）, [Zn（H3L）（bipy）（H2O）]·H2O（3）, have been hydrothermally obtained and characterized by powder X-ray diffraction（PXRD）, IR, elemental analysis, TG-DSC. The singlecrystal X-ray diffractions show that compound 1 possesses one-dimensional ladder-like double chain structure with two unique Zn（Ⅱ） ions in 4-and 6-coordinated modes, respectively. Compound 2 displays zero-dimensional structure built from binuclear unit [Zn O3N2]2by a double O-P-O bridge. Compound 3 also shows one-dimensional chain structure built from octahedron [Zn O4N2] by a single O-P-O bridge. Then H-bond or/and π-π interactions further expand the one-and zero-dimensional structures into the three-dimensional supramolecular frameworks.Fluorescent measurements reveal that the maximum emission peaks of 1~3 have a significant increase in intensity compared to that of the bipy ligand, centered at 374 nm for 1, 388 nm for 2 and 387 nm for 3, respectively.These peaks are mainly caused by intraligand π＊-π emission state of the bipy ligand（λem=391 nm, λex=252 nm）.All the three compounds indicate a one-electron oxidation process based on electrochemical measurements and the donor ability of 1~3 has gone up, compared with the H5 L and the bipy ligands. CCDC： 1001967, 1; 1001968,2; 1001969, 3.