On the oxidation states of metal elements in MO-3(M=V,Nb,Ta,Db,Pr,Gd,Pa)anions  

作　　者：Jing Su Shuxian Hu Wei Huang Mingfei Zhou Jun Li 

机构地区：[1]Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education,Department of Chemistry,Tsinghua University,Beijing 100084,China [2]Collaborative Innovation Center of Chemistry for Energy Materials Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials,Department of Chemistry,Fudan University,Shanghai 200433,China

出　　处：《Science China Chemistry》2016年第4期442-451,共10页中国科学（化学英文版）

基　　金：supported by the National Basic Research Program of China(2013CB834603);the National Natural Science Foundation of China(21173053,21433005,91426302,21221062,21201106)

摘　　要：Relativistic quantum chemistry investigations are carried out to tackle the puzzling oxidation state problem in a series of MO3 trioxide anions of all d- and f-block elements with five valence electrons. We have shown here that while the oxidation states of V, Nb, Ta, Db, Pa are, as usual, all ＋V with divalent oxygen O（-II） in MO3- anions, the lanthanide elements Pr and Gd cannot adopt such high ＋V oxidation state in similar trioxide anions. Instead, lanthanide element Gd retains its usual ＋III oxi- dation state, while Pr retains a ＋IV oxidation state, thus forcing oxygen into a non-innocent ligand with an uncommon mono- valent radical （O＇） of oxidation state -I. A unique Pr＂- ＂（0）3 biradical with highly delocalized unpairing electron density on Pr（IV） and three O atoms is found to be responsible for stabilizing the monovalent-oxygen species in PRO3- ion, while GdO3 ion is in fact an OGd＋（O22-） complex with Gd（III）. These results show that a naive assignment of oxidation state of a chemical element without electronic structure analysis can lead to erroneous conclusions.Relativistic quantum chemistry investigations are carried out to tackle the puzzling oxidation state problem in a series of MO_3^- trioxide anions of all d- and f-block elements with five valence electrons. We have shown here that while the oxidation states of V, Nb, Ta, Db, Pa are, as usual, all +V with divalent oxygen O(-II) in MO_3^- anions, the lanthanide elements Pr and Gd cannot adopt such high +V oxidation state in similar trioxide anions. Instead, lanthanide element Gd retains its usual +III oxidation state, while Pr retains a +IV oxidation state, thus forcing oxygen into a non-innocent ligand with an uncommon monovalent radical(O~·) of oxidation state -I. A unique Pr·- ·(O)_3 biradical with highly delocalized unpairing electron density on Pr(IV) and three O atoms is found to be responsible for stabilizing the monovalent-oxygen species in PrO_3^- ion, while GdO_3^- ion is in fact an OGd^+(O_2^(2-)) complex with Gd(III). These results show that a na?ve assignment of oxidation state of a chemical element without electronic structure analysis can lead to erroneous conclusions.

关 键 词：oxidation state non-innocent ligand BIRADICAL LANTHANIDE trioxide anion 

分 类 号：O641.1[理学—物理化学]