Co-btec配合物的合成、结构及表面光电性能

采用水热以及微波合成方法得到了3 种Co(II)配合物: Na2Co(μ4-btec)(H2O)8]n(1)、Co2(μ2-btec)(bipy)2(H2O)6]·2H2O(2)和Co2(μ2-btec)(phen)2(H2O)6]·2H2O (3) (H4btec=1,2,4,5-苯四甲酸, bipy= 2,2'-联吡啶, phen=邻菲咯啉). X 射线单晶衍射结果表明, 配合物(1)属于单斜晶系, C2/m空间群, 晶胞参数为a=1.5690(2) nm, b=0.9550(6) nm, c=0.6102(2) nm, β=92.78(3)°. 配合物(2)也属于单斜晶系, P21/n 空间群,晶胞参数为a=1.2290(1) nm, b=0.7594(2) nm, c=1.7920(1) nm, β=100.07(2)°. 配合物(3)属于三斜晶系, P1空间群, 晶胞参数为a=0.7454(1) nm, b=1.1072(2) nm, c=1.2177(2) nm, α=108.41(3)°, β=101.94(3)°, γ=109.03(3)°. 3个配合物都是以均苯四甲酸根为桥, 形成三维(1)和双核(2、3)结构. 但在3种配合物中, 均苯四甲酸根的配位模式各不相同, 分别采用了μ4-η2η2η2η2、μ2-η1η1和μ2-η1η1配位模式.此外,分子间大量氢键又将配合物(2)和(3)分别网成了二维和三维无限结构. 通过红外光谱(IR)、紫外-可见-近红外(UV-Vis-NIR)光谱及表面光电压光谱(SPS)等方法对配合物进行了表征. 3个配合物的表面光电压谱研究表明, 它们在300-600 nm 范围内均有正的光伏响应. 但它们的SPS响应带的宽度、位置和数目存在一定差异, 这是由它们的结构和三者中Co 离子的配位微环境不同造成的. 将SPS与其电子吸收光谱进行关联, 发现它们基本上是一致的.

Syntheses, Structures, and Surface Photoelectric Properties of Co-btec Complexes

Three new mixed-ligand cobalt(II) complexes Na2Co(μ4-btec)(H2O)8]n (1), Co2(μ2-btec)(bipy)2(H2O)6]·2H2O (2), and Co2(μ2-btec)(phen)2(H2O)6]·2H2O (3) (H4btec = 1,2,4,5-benzenetetracarboxylic acid, bipy=2,2'-bipyridine, phen=1,10-phenanthroline) were synthesized using hydrothermal and microwave methods after which the products were characterized by single crystal X-ray diffraction. Complex (1) crystallizes in a monoclinic systemwith a C2/m space group, a=1.5690(2) nm, b=0.9550(1) nm, c=0.6102(2) nm, and β=92.78(3)°. Complex (2) belongs to a monoclinic systemand has a P21/n space group, a=1.2290(1) nm, b=0.7594(2) nm, c=1.7920(1) nm and β=100.07(2)°. Complex (3) belongs to a triclinic systemand has a P1 space group, a=0.7454(1) nm, b=1.1072(2) nm, c=1.2177(2) nm, α=108.41(3)°, β=101.94(3)°, and γ=109.03(3)°. All three complexes are bridged by the betc4- ligands to form 3 dimensional (D) (1) and binuclear (2and 3) structures. The betc4- ligands adopt μ4-η2η2η2η2, μ2-η1η1, and μ2-η1η1 coordinated modes in the three complexes, respectively. The hydrogen bonds allow complexes (2) and (3) to be further connected into 2D and 3D networks. The complexes were characterized by IR, UV-visible-near infrared (UV-Vis-NIR), and surface photovoltage spectroscopy (SPS). The SPS of the three complexes (1)-(3) indicate that they all exhibit positive surface photovoltage (SPV) responses from 300 to 600 nm. However, the intensity, position, and number of SPV responses are different, which may be attributed to the differences in their structures and coordination environment of the Co ions in the three complexes. The SPS results are consistent with associated UV-Vis-NIR spectrumresults.