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
Understanding the reaction mechanism at the atomic and molecular level is a central task of chemistry.Within the Born-Oppenheimer approximation,a chemical reaction is envisioned as nuclear dynamics evolving from react...Understanding the reaction mechanism at the atomic and molecular level is a central task of chemistry.Within the Born-Oppenheimer approximation,a chemical reaction is envisioned as nuclear dynamics evolving from reactants to products on a potential energy surface(PES).To reveal the detailed mechanistic origin of such an old bond-breaking and new bond-forming process,a measurement of state-to-state differential cross-sections(DCSs)is essential.Its fine structure often serves as a fingerprint to identify quantum dynamics phenomena in a bimolecular reactive encounter.Observation of these fine structures is,however,difficult,because the interference feature may appear in the state-to-state DCSs only with very high angular resolution。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.
文摘Understanding the reaction mechanism at the atomic and molecular level is a central task of chemistry.Within the Born-Oppenheimer approximation,a chemical reaction is envisioned as nuclear dynamics evolving from reactants to products on a potential energy surface(PES).To reveal the detailed mechanistic origin of such an old bond-breaking and new bond-forming process,a measurement of state-to-state differential cross-sections(DCSs)is essential.Its fine structure often serves as a fingerprint to identify quantum dynamics phenomena in a bimolecular reactive encounter.Observation of these fine structures is,however,difficult,because the interference feature may appear in the state-to-state DCSs only with very high angular resolution。
