辛酰丙氨酸稀土(Y,La,Eu)配合物的稀土原子配位近邻结构的EXAFS研究

EXAFS Studies of Neighbor Structure of Rare Earth Atom Ligand in Capryloyl Alaninate Rare Earth (Y,La,Eu) Complexes

由摩尔比为3∶1辛酰丙氨酸配体和稀土卤化物作为反应物,通过化学反应制备出三种稀土配合物。将配合物在有机溶液中进行净化处理,再经过加热（110℃）和冷却（25℃）处理后得到结晶态与非晶态性质的稀土配合物。元素分析、^13C-NMR和水分测定分析结果确定金属配合物的分子组成。XRD衍射曲线证实了这些金属配合物具有周期性长程有序/无序结构,并发现了稀土配合物易形成多样化状态物质。使用同步辐射扩展X射线吸收精细结构（EXAFS）方法对稀土配合物样品进行结构解析,通过数据最小二乘拟合给出样品中稀土原子周围近邻配位氧原子配位数、配位距离和Debye-Waller因子等结构参数。结果表明,钇及镧离子—O结合的配位数在一水和配合物中为接近7（6＋1）,二水和配合物中为接近8（6＋2）。全系配合物中铕离子—O结合的配位数全部系内几乎等于8（6＋2）。

Three kinds of rare earth complexes were prepared by chemical reaction from octanoylalanine ligand crystal and rare earth halide with mole ratio of 3 ∶ 1. The complexes were purified in organic solution and then heated to 110℃ and cooled to 25℃ before obtaining rare earth complexes with a nature of the crystalline and amorphous state. Elemental analysis,13 CNMR and moisture determination confirm the molecular composition of metal complexes. XRD diffraction data confirmes the periodic long range order/disorder structure of these metal complexes. It is also found that the diversified material is easily formed from rare earth complexes. By EXAFS analysis and the least squares fitting,the structure parameters of given samples were obtained,which are ligand oxygen coordination number of rare earth atoms surrounding neighbors,distance of ligand and Debye-Waller factor. Results show that the coordination number of yttrium and lanthanum ion-O combination is close to7（ 6＋1） in monohydrate complexes and 8（ 6 ＋ 2） in dihydrate complexs. The coordination number of Eu ion-O binding is almost equal to 8（ 6＋2） in all systems.