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首次利用2-氟异烟酸为配体合成并表征了6例一维螺旋链稀土离子配位聚合物,分别为:{[Ln(FINA)3(H2O)2]·H2O}n(Ln=Pr(1),Nd(2),Eu(3),Gd(4)),{[Dy(FINA)3(H2O)2]}n(5)和{[Gd(FINA)2(phen)(OH)]}n(6)(HFINA=2-氟异烟酸,phen=1,10-邻菲罗啉),其中1~4为相同构型。由于镧系收缩效应的影响,配体在1~5中表现出不同的配位模式而稀土离子也呈现不同的配位构型。这些一维链通过分子间强的O-H…O/N氢键和芳环间的π…π作用以及C-H…F氢键等丰富的分子间力连接成三维超分子结构。有趣的是在化合物1~4中存在可以容纳一个水分子的一维溶剂分子孔道。荧光测试表明:配合物3表现出铕离子的特征红色荧光,荧光寿命为333.81μs;而4则表现出配体特征的荧光。变温磁化率测试表明在2~6中稀土离子间表现为弱的反铁磁相互作用。热重分析表明所合成的配合物均有较好的热稳定性。
For the first time, six 1-D helix chain rare earth ion coordination polymers were synthesized and characterized by using 2-fluoroisonicotinic acid as ligands, which are respectively as follows: {[Ln (FINA) 3 (H2O) 2] Pr (1), Nd (2), Eu (3), Gd (4), {[Dy (FINA) 3 (H2O) 2]} n (5) and {[Gd (FINA) 2 OH)]} n (6) (HFINA = 2-fluoroisonicotinic acid, phen = 1,10-phenanthroline), wherein 1 to 4 are the same configuration. Due to the effect of lanthanide shrinkage, the ligands show different coordination modes in 1 ~ 5 and rare earth ions show different coordination configurations. These one-dimensional chains are strongly linked to each other by the strong intermolecular O-H ... O / N hydrogen bonds and the π ... π interaction between the aromatic rings and the C-H ... F hydrogen bonds to form three-dimensional supramolecular structures. It is interesting to note that in compounds 1 to 4, one-dimensional solvent molecular channels exist that accommodate one water molecule. Fluorescence test showed that complex 3 showed the characteristic red fluorescence of europium ion, the fluorescence lifetime was 333.81μs, while the fluorescence spectrum of ligand 3 was shown by 4. Variable temperature magnetic susceptibility tests show that rare earth ions exhibit weak anti-ferromagnetic interactions in 2-6. Thermogravimetric analysis showed that the synthesized complexes have better thermal stability.