Halogen versus halide electronic structure

作     者：Willem-Jan van Zeist F.Matthias Bickelhaupt 

作者机构：Department of Theoretical Chemistry and Amsterdam Center for Multiscale ModelingScheikundig Laboratorium der Vrije UniversiteitDe Boelelaan 1083NL-1081 HV AmsterdamThe Netherlands 

出 版 物：《Science China Chemistry》 (中国科学（化学英文版）)

年 卷 期：2010年第53卷第1期

页      面：210-215页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：supported by the National Research School Combination-Catalysis (NRSC-C) the Netherlands Organization for Scientific Research (NWO-CW and NWO-NCF) 

主　　题：bond theory halogen hydrogen-atom affinity orbital energy proton affinity reactivity 

摘      要：Halide anions X-are known to show a decreasing proton affinity(PA),as X descends in the periodic table along series F,Cl,Br and *** it is also well-known that,along this series,the halogen atom X becomes less electronegative(or more electropositive).This corresponds to an increasing energy of the valence np atomic orbital(AO) which,somewhat contradictorily,suggests that the electron donor capability and thus the PA of the halides should increase along the series F,Cl,Br,*** reconcile these contradictory observations,we have carried out a detailed theoretical analysis of the electronic structure and bonding capability of the halide anions X-as well as the halogen radicals X-,using the molecular orbital(MO) models contained in Kohn-Sham density functional theory(DFT,at SAOP/TZ2P as well as OLYP/TZ2P levels) and ab initio theory(at the HF/TZ2P level).We also resolve an apparent intrinsic contradiction in Hartree-Fock theory between orbital-energy and PA *** results of our analyses are of direct relevance for understanding elementary organic reactions such as nucleophilic substitution(SN2) and base-induced elimination(E2) reactions.