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在4-甲基咪唑/三氮唑存在下,利用四氟对苯二甲酸为配体、与Pb(NO3)2作用,得到了2种配位聚合物{[Pb(tfbdc)(H2tfbdc)0.5]·(4-MI)·(H2O)}n(1)和{[Pb(tfbdc)(H2O)2]}n(2)(H2tfbdc=四氟对苯二甲酸,4-MI=4-甲基咪唑),并用红外光谱、元素分析和X-单晶衍射对其进行了表征。化合物1属于单斜晶系,空间群为P21/n,化合物2属于三斜晶系,空间群为P1。配合物1中,铅离子依靠正常的Pb-O键和次级键Pb…O,与7个氧原子配位;tfbdc2-阴离子和H2tfbdc分别采用不同的配位方式桥联铅离子,导致1个具有孔道的三维结构的形成。而4-甲基咪唑和游离水分子通过氢键作用嵌在这三维结构的孔道中。π-π堆积作用的存在增强了1的稳定性。配合物2中,铅离子是位于8个氧原子的配位环境中,tfbdc2-阴离子以螯合和桥联的方式与铅离子作用,导致1个二维层状结构的形成。此外还考察了1和2的热稳定性和固体荧光性质。
Two kinds of coordination polymers {[Pb (tfbdc) (H2tfbdc) 0.5] were synthesized by the reaction of Pb (NO3) 2 with tetrafluoroterephthalic acid in the presence of 4-methylimidazole / (4-MI) · (H2O)} n (1) and {[Pb (tfbdc) (H2O) 2]} n (2) (H2tfbdc = tetrafluoroterephthalic acid, 4-MI = Imidazole) were synthesized and characterized by FTIR, elemental analysis and X-ray single crystal diffraction. Compound 1 belongs to monoclinic system with space group P21 / n, compound 2 belongs to triclinic system and space group P1. In complex 1, the lead ion relied on the normal Pb-O bond and the secondary bond Pb ... O to coordinate with seven oxygen atoms; tfbdc2- anion and H2tfbdc bridged the lead ions by different coordination methods respectively, resulting in one Formation of a three-dimensional structure with channels. However, 4-methylimidazole and free water molecules are embedded in the pores of this three-dimensional structure by hydrogen bonding. The presence of π-π stacking enhances the stability of 1. In complex 2, the lead ions are located in the coordinate environment of eight oxygen atoms. The tfbdc2- anion interacts with lead ions in a chelating and bridging manner, resulting in the formation of a two-dimensional layered structure. In addition, the thermal stability and solid fluorescence properties of 1 and 2 were investigated.