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C−F Bond Activation by a Saturated N‐Heterocyclic Carbene: Mesoionic Compound Formation and Adduct Formation with B(C 6 F 5 ) 3
Author(s) -
Pait Moumita,
Kundu Gargi,
Tothadi Srinu,
Karak Suvendu,
Jain Shailja,
Vanka Kumar,
Sen Sakya S.
Publication year - 2019
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.201814616
Subject(s) - mesoionic , carbene , chemistry , moiety , adduct , deprotonation , medicinal chemistry , stereochemistry , lewis acids and bases , crystallography , ion , catalysis , organic chemistry
The reaction of SIPr, [1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene] ( 1 ), with C 6 F 6 led to the formation of an unprecedented mesoionic compound ( 2 ). The formation of 2 is made accessible by deprotonation of the SIPr backbone with simultaneous elimination of HF. The C−F bond para to the imidazolium ring in 2 is only of 1.258(4) Å, which is the one of the shortest structurally authenticated C−F bonds known to date. The liberation of HF during the reaction is unequivocally proved by the addition of one more equivalent of SIPr, which leads to the imidazolium salt with the HF 2 − anion. To functionalize 2 , the latter reacted with B(C 6 F 5 ) 3 to give an unusual donor–acceptor compound, where the fluoride atom from the C 6 F 5 moiety coordinates to B(C 6 F 5 ) 3 and the carbanion moiety remains unaffected. Such coordination susceptibility of the fluoride atom of a nonmetallic system to a main‐group Lewis acid (F non‐metal →BR 3 ) is quite unprecedented.