以芳香族多羧酸为配体的Ni(Ⅱ)配位超分子的研制及光诱导下的表面电子行为

Preparation and Light-Induced Surface Electron Behavior of Ni(Ⅱ) Based on Aromatic Polycarboxyl Acids

采用水热方法合成了2个Ni(Ⅱ)配合物[Ni3(btc)2(H2O)14]·4H2O(1)和[Ni2(btec)(bipy)2(H2O)6]·2H2O(2),(H3btc=1,3,5-benzenetricarboxylic acid,H4btec=1,2,4,5-benzenetetracarboxylic acid,bipy=2,2′-bipyridyl).通过X射线单晶衍射(XRD)、红外光谱(IR)、紫外-可见-近红外吸收光谱(UV-Vis-NIR)对化合物进行了表征.结果表明,化合物(1)是由2个均苯三甲酸根桥连的三核Ni(Ⅱ)离子的化合物,而化合物(2)是由1个均苯四甲酸根桥连的双核化合物,分子中bipy分子作为端基配体.分子中大量的水分子和羧酸根的存在使2个化合物分别被连成具有三维(3D)和二维(2D)结构的配位超分子化合物.着重研究了化合物的表面光电压光谱(SPS),并将其与UV-Vis-NIR吸收光谱进行了分析和对比,发现SPS中表面光伏响应带与UV-Vis-NIR吸收光谱的吸收峰在数量和位置上都是一一对应的.此外,对比2个化合物的表面光电压光谱可以看出,配合物的结构及中心金属的配位微环境对其表面光伏响应带的强度、位置和形状均有一定影响.

Two nickel coordination complexes [Ni3（btc）2（H2O）14]·4H2O（1）, [Ni2（btec）（bipy）2（H2O）6]·2H2O（2）,（H3btc=1,3,5-benzenetricarboxylic acid,H4btec=1,2,4,5-benzenetetracarboxylic acid,bipy=2,2′-bipyridyl） were synthesized hydrothermally and characterized by single crystal X-ray diffraction （XRD）, infrared （IR） and Ultravialet- Visible-Near Infrared （UV-Vis-NIR） spectra. Result indicate that complex （1） is a trinuclear complex bridged by btc groups and complex （2） is a binuclear complex connected by btec groups. The existence of hydrogen bonds allows complexes （1） and （2） to become coordination supramolecules with three dimensional （3D） and two dimensional （2D） infinite structures, respectively. Surface photovoltage spectrum （SPS） of these complexes exhibits positive surface photovoltage responses from 300--800 nm. However, the intensity, position and shape of these response bands are obviously different. This distinction might be responsible for the structures and coordination environments of nickel ions in these complexes. By contrasting SPS with UV-Vis-NIR spectra we find that these response bands in SPS are consistent with absorption peaks in the UV-Vis-NIR spectra.