Using pyrazine-2-carboxylic acid (2-Hpzc), 3,5-pyridinedicarboxylic acid (3,5-H(2)PDA) and oxalic acid (H(2)ox) as ligands, nine Ag-Ln coordination polymers are synthesized by hydrothermal methods: {[LnAg(2-pzc)(2)(ox)]center dot H(2)ox} (Ln=Pr (1), Nd (2), Sm (3), Eu (4)), [LnAg(3,5-PDA)(ox)(H2O)](n), (Ln=Pr (5), Nd (6)), [LnAg(3,5-PDA)(3,5-HPDA)(ox)(0.5)(H2O)(2)](n) (Ln=Sm (7), Dy (8), Ho (9)). All of them possess the 3D network structure, i.e., coordination polymers 1 similar to 4 are isomorphic and connected by 2-pzc(-) and ox(2-), while coordination polymers 5 similar to 9 use 3,5-PDA(2-) and ox(2-) as bridging ligands. Photophysical properties of these coordination polymers are studied, and they show characteristic emissions of corresponding Ln(III) ions which should be attributed to the sensitization of the Agligand section (d-block). In addition, under the co-action of crystal field and 4d orbits of Ag(I) ion, the 4f orbits of Ln(III) ions are tuned and cause obvious shift of partial energy levels, which present shifts of the corresponding NIR emission bands and can be corroborated in their UV-Vis-NIR absorption spectra. CCDC: 1817276, 1; 1817247, 2; 1817248, 3; 1817249, 4; 1817251, 5; 1817255, 6; 1817269, 7; 1817280, 8; 1817285, 9.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Six Ln–Ag coordination polymers {[LnAg2(IN)4(H2O)5]·NO3·2H2O}n (Ln=Ho (1) and Tb (2), HIN=isonicotinic acid), {[PrAg2(IN)4(H2O)2]·NO3·H2O}n (3), [LnAg(pdc)2]n (Ln=Eu(4) and Pr (5), H2pdc=3,4-pyridine-dicarboxylic acid) and [NdAg(bidc)2(H2O)4]n (6) (H2bidc=benzimidazole-5,6-dicarboxylic acid) have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, elemental analysis, IR, UV–vis-NIR absorption spectra, fluorescence spectra and thermogravimetric analysis. Structural analyses reveal that the six polymers exhibit 0D (polymer (1)), 1D (polymer (2)), 2D (polymers (3) and (5)) and 3D (polymers (4) and (6)) infinite structures, respectively. Polymers (1)–(6) exhibit the Ln(III) characteristic emission in the near-infrared (NIR) region or in the visible region. Especially, the NIR emission bands of polymers 1, 5 and 6 evidently present shift or splitting due to formation of the Ln–Ag coordination polymers. This can be attributed to the tune of inner levels in Ln–Ag system caused by the interact and influence between the 4d orbital of the Ag(I) ion and the 4f orbital of the Ln(III) ion, which can be confirmed by the UV–vis-NIR absorption spectra of the polymers. In addition, the distortion of coordination geometry as well as difference of the coordination number around the Ag(I) ion affect the structure framework.
采用水热合成方法,以氨三乙酸为配体,合成了1种Tb(Ⅲ)的配位聚合物{[TbN(CH2CO2)3(H2O)2].H2O}n,通过单晶X射线衍射确定了该配合物的晶体结构.该配合物属正交晶系,Pbca空间群,晶胞参数为a=0.809 38(7)nm,b=1.298 43(11)nm,c=2.061 70(18)nm,V=2.166 7(3)nm3,R1=0.025 8,wR2=0.055 8.配合物的不对称单元为[TbN(CH2CO2)3(H2O)2].H2O,其中Tb(Ⅲ)离子为8配位.在晶体中,Tb(Ⅲ)离子之间通过氨三乙酸根的氮原子和羧基氧原子连接,最终在ab面上形成2D层状结构.在室温下,测定了该配合物晶体粉末的激发光谱、发射光谱、IR和UV-Vis,并对其进行了分析指认.发射光谱研究表明,该配合物固态粉末在室温紫外光的照射下可发射较强的绿光,并表现出较强的Tb(Ⅲ)的特征发射.