大环化合物的合成、结构及其对镧(Ⅲ)离子的识别研究

Synthesis, Structures of Macrocyclic Compounds and Study on Recognition for La(Ⅲ) Ion

在Ba2+离子诱导作用下,采用前体二醛1[1,2-双(2'-甲酰苯氧基)乙烷]和前体二胺2[间苯二酚-双(4-胺基苯基)醚]进行缩合,得到[1+1]Schiff碱大环化合物3,进一步将大环3还原得大环4,用1H NMR,IR,质谱和元素分析等对其组成进行了表征.采用X射线衍射技术测定了大环3和相应的还原产物4的晶体结构.结构解析结果表明,大环3的分子呈折叠结构,4表现为扭曲的非叠结构.采用UV-vis光谱技术,对大环与系列稀土离子的键合作用进行了考察,结果表明,大环化合物3对镧(Ⅲ)离子具有选择性识别作用.进一步采用Job法确定了大环3与镧(Ⅲ)离子配位作用的键合比为1∶1,键合常数为7.59×103.

[1＋1] Schiff base macrocyclic compound 3 has been synthesized from precursor 1 [1,2-bis（2＇-formacylphenoxy）ethane] and precursor 2 [2-resorcinol-bis（4-aminophenyl）ether] via condensation and cyclization using Ba2＋ as template. The macrocycle 3 was further reduced giving macrocyclic compound 4, and the structures were characterized by tH NMR, IR, MS and elemental analysis, respectively. The X-ray single crystal analysis reveals that the maerocycle 3 has a folding structure, and 4 shows a twisted unfolding structure. The study for the reaction of the macrocyclic compound 3 or 4 with a series of the rare earth ions is performed by UV-Vis absorption spectra technique, and the results show that the macrocycle 3 displayed a selective recognition for La3＋ ion. Moreover, the JOB plot exhibited a 1 ：1 （host ： guest） stoichiometry between the host 3 and La3＋, and the binding constant （K） was determined using UV-vis titration method, K=7.59×10^3.