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...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.展开更多
Single-electron oxidation of a diiron-sulfur complex [Cpπ＊Fe（μ-bdt）FeCp^＊] （1, Cp^＊=η^5-C5Me5; bdt = benzene-1,2-dithiolate） to [Cp^＊Fe（μ-bdt）FeCp^＊]]^＋ （2） has been experimentally conducted. The bdt...Single-electron oxidation of a diiron-sulfur complex [Cpπ＊Fe（μ-bdt）FeCp^＊] （1, Cp^＊=η^5-C5Me5; bdt = benzene-1,2-dithiolate） to [Cp^＊Fe（μ-bdt）FeCp^＊]]^＋ （2） has been experimentally conducted. The bdt ligand with redoxactive character has been computationally proposed to be a dianion （bdt62-） rather than previously proposed monoanion （bdt^-） radical in 1 though it has un-equidistant aromatic C-C bond lengths. The ground state of 1 is predicted to be two low-spin ferrous ions （SFe= 0） and 2 has a medium-spin ferric ion （SFe= 1/2） and a low-spin ferrous center （SFe=0）, and the oxidation of 1 to 2 is calculated to be a single-metal-based process. Both complexes have no significant antiferromagnetic coupling character.展开更多
基金supported by the National Basic Research Program of China(2013CB834603)the National Natural Science Foundation of China(21173053,21433005,91426302,21221062,21201106)
文摘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.
基金This work was partly supported by the National Natural Science Foundation of China （Nos. 21429201, 21231003, 21571026）. The authors also thank the Network and Information Center of the Dalian University of Technology for part of the computational resources.
文摘Single-electron oxidation of a diiron-sulfur complex [Cpπ＊Fe（μ-bdt）FeCp^＊] （1, Cp^＊=η^5-C5Me5; bdt = benzene-1,2-dithiolate） to [Cp^＊Fe（μ-bdt）FeCp^＊]]^＋ （2） has been experimentally conducted. The bdt ligand with redoxactive character has been computationally proposed to be a dianion （bdt62-） rather than previously proposed monoanion （bdt^-） radical in 1 though it has un-equidistant aromatic C-C bond lengths. The ground state of 1 is predicted to be two low-spin ferrous ions （SFe= 0） and 2 has a medium-spin ferric ion （SFe= 1/2） and a low-spin ferrous center （SFe=0）, and the oxidation of 1 to 2 is calculated to be a single-metal-based process. Both complexes have no significant antiferromagnetic coupling character.
