乙异羟肟酸与U、Np、Pu配合物的结构和热力学性质的密度泛函理论研究

Density Functional Theoretical Analysis of Complexes of AHA and U,Np and Pu

采用密度泛函理论(DFT),在B3LYP/RECP/6-31G(d,p)水平对U(Ⅵ)、U(Ⅳ)、Np(Ⅳ)、Pu(Ⅳ)与乙异羟肟酸(AHA)摩尔比为1∶1和1∶2配合物的结构和热力学参数进行了研究。结构计算发现,M-O键键长随原子序数增加而减短,对配合物进行自然轨道分析(NBO)发现,M和AHA的摩尔比为1∶1的配合物中M-O键是明显的离子键,共价成分很少,在1∶2配合物中M-O键共价成分增加。对配位反应的热力学参数进行计算发现,金属离子与AHA配合物的稳定性依次为Pu(Ⅳ)>Np(Ⅳ)>U(Ⅳ)>U(Ⅵ),理论计算结果与实验测量得到的稳定常数顺序一致。

The geometry and thermodynamic properties of complexes of acetohydroxamic acid （AHA） and U, Np and Pu （1 ： 1 and 2 ： 1） were studied by using density functional theory （DFT） at B3LYP/RECP/6-31G（d,p） level. The structure studies show the shortening of M-O bond in complexes along with the inereasement of atomic number. NBO analysis show the M-O bonds in the complexes with the mole ratio 1-1 of M and AHA are representative ionic bonds. However, the M-O bonds in 1 ： 2 complexes are partial covalent bond compo- nents. Thermodynamic property studies reveal the order of the stability of metal AHA complexes is Pu（Ⅳ）〉Np（Ⅳ）〉U（Ⅳ）〉U（Ⅳ）. The experiment results are agreement with the theoretical studies.