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Cationic Heterobimetallic Mg(Zn)/Al(Ga) Combinations for Cooperative C–F Bond Cleavage
Author(s) -
Friedrich Alexander,
Eyselein Jonathan,
Langer Jens,
Färber Christian,
Harder Sjoerd
Publication year - 2021
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.202103250
Subject(s) - chemistry , cationic polymerization , bond cleavage , cleavage (geology) , metal , covalent bond , lewis acids and bases , crystallography , solvent , medicinal chemistry , stereochemistry , polymer chemistry , organic chemistry , catalysis , materials science , composite material , fracture (geology)
Low‐valent ( Me BDI)Al and ( Me BDI)Ga and highly Lewis acidic cations in [( tBu BDI)M + ⋅C 6 H 6 ][(B(C 6 F 5 ) 4 − ] (M=Mg or Zn, Me BDI=HC[C(Me)N‐DIPP] 2 , tBu BDI=HC[C( t Bu)N‐DIPP] 2 , DIPP=2,6‐diisopropylphenyl) react to heterobimetallic cations [( tBu BDI)Mg–Al( Me BDI) + ], [( tBu BDI)Mg–Ga( Me BDI) + ] and [( tBu BDI)Zn–Ga( Me BDI) + ]. These cations feature long Mg–Al (or Ga) bonds while the Zn–Ga bond is short. The [( tBu BDI)Zn–Al( Me BDI) + ] cation was not formed. Combined AIM and charge calculations suggest that the metal–metal bonds to Zn are considerably more covalent, whereas those to Mg should be described as weak Al I (or Ga I )→Mg 2+ donor bonds. Failure to isolate the Zn–Al combination originates from cleavage of the C−F bond in the solvent fluorobenzene to give ( tBu BDI)ZnPh and ( Me BDI)AlF + which is extremely Lewis acidic and was not observed, but ( Me BDI)Al(F)‐(μ‐F)‐(F)Al( Me BDI) + was verified by X‐ray diffraction. DFT calculations show that the remarkably facile C–F bond cleavage follows a dearomatization/rearomatization route.