一系列水合和非水合铀酰卤族(F,Cl,Br)配合物在水溶液中的结构和紫外吸收光谱性质的密度泛函理论研究  

A DFT Study on Properties of Geometries and UV-Vis Spectra of Hydrated and Non-hydrated Uranyl Halides(F,Cl,Br) in Aqueous Phase

作　　者：辜家芳[1] 满梅玲[1] 陆春海[2] 陈文凯[1] 

机构地区：[1]福州大学化学系,福州350116 [2]成都理工大学核技术与自动化工程学院,成都610059

出　　处：《无机化学学报》2012年第7期1324-1332,共9页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.10676007);福建省高等学校新世纪优秀人才计划(No.HX2006-103)资助项目

摘　　要：本文考虑相对论效应并应用密度泛函理论(DFT)研究水溶液中UO2Xn(H2O)5-n(X=F,Cl,Br;n=1～4)和UO2Xn(X=F,Cl,Br;n=1～6)一系列水合和非水合铀酰化合物的结构和紫外吸收光谱性质。将这一系列物质命名为Xnm(X为F,Cl,和Br;n为卤素配体个数,m为水分子配体的个数)。在水溶液中,溶剂化效应采用类导体屏蔽模型(COSMO)并采用SAS溶剂接触曲面构造空穴模拟水溶剂对配合物的作用。配合物的紫外光谱性质采用考虑旋-轨耦合相对论效应的含时密度泛函(SO-TD-DFT)进行计算。U=O键随着F配体数目的增加而明显伸长,然而随Cl和Br配体数目的增加变化较小。随X配体数目的增加和水分子参与配位,铀与X的结合能逐渐减弱。配合物的紫外光谱计算表明铀酰氟的各种配合物并不出现特征吸收峰,而铀酰氯和铀酰溴的各种配合物均有特征吸收光谱。通过分子轨道分析可以很好解释光谱所体现的特征。A systematic study of series of hydrated UO2Xn（H20）5-n （X=F, C1, Br; n=l-4） and non-hydrated UOEXn （X=F, C1, Br; n=1-6） of halides on properties of geometries and UV-Vis Spectra in aqueous phase has been carried out using relativistic density functional theory. Xnm forms are used to name the series of uranyl halides （X =F, C1, Br; n is the number of halogen ligand, and m is the number of water molecular ligaud in uranyl complexes）. Solvent effects estimated by the conductor-like screening model （COSMO） use the solvent accessible surface （SAS）. Time-dependent density functional theory includes spin-orbit coupling relativistic effects （SO-TD- DPF） is used to calculate UV-Vis absorption spectra. The increase of F ligand in structure elongate the U =O bond significantly, however the number of Cl and Br ligands make small changes in bond U--O. With the increasing in number of X ligand and water molecules participate in coordination, the binding energy of U and X ligand can be gradually reduced. The calculated UV-Vis absorption spectra indicate that uranyl fluoride complexes does not appear the characteristic absorption peak, and uranyl chloride and uranyl bromide complexes have various features in the absorption spectrum. And molecular orbital analysis can well explain the characteristics of spectrum.

关 键 词：铀酰离子 密度泛函理论 旋-轨耦合相对论效应 溶剂化 紫外吸收光谱 

分 类 号：O641[理学—物理化学]