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Superelectrophilic Behavior of an Anion Demonstrated by the Spontaneous Binding of Noble Gases to [B 12 Cl 11 ] −
Author(s) -
Rohdenburg Markus,
Mayer Martin,
Grellmann Max,
Jenne Carsten,
Borrmann Tobias,
Kleemiss Florian,
Azov Vladimir A.,
Asmis Knut R.,
Grabowsky Simon,
Warneke Jonas
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201702237
Subject(s) - electrophile , chemistry , adduct , nucleophile , reactivity (psychology) , ion , covalent bond , molecule , chemical polarity , dipole , xenon , computational chemistry , photochemistry , organic chemistry , medicine , alternative medicine , pathology , catalysis
It is common and chemically intuitive to assign cations electrophilic and anions nucleophilic reactivity, respectively. Herein, we demonstrate a striking violation of this concept: The anion [B 12 Cl 11 ] − spontaneously binds to the noble gases (Ngs) xenon and krypton at room temperature in a reaction that is typical of “superelectrophilic” dications. [B 12 Cl 11 Ng] − adducts, with Ng binding energies of 80 to 100 kJ mol −1 , contain B−Ng bonds with a substantial degree of covalent interaction. The electrophilic nature of the [B 12 Cl 11 ] − anion is confirmed spectroscopically by the observation of a blue shift of the CO stretching mode in the IR spectrum of [B 12 Cl 11 CO] − and theoretically by investigation of its electronic structure. The orientation of the electric field at the reactive site of [B 12 Cl 11 ] − results in an energy barrier for the approach of polar molecules and facilitates the formation of Ng adducts that are not detected with reactive cations such as [C 6 H 5 ] + . This introduces the new chemical concept of “dipole‐discriminating electrophilic anions.”