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Mono‐reduced Corannulene: To Couple and Not to Couple in One Crystal
Author(s) -
Rogachev Andrey Yu.,
Alkan Melisa,
Li Jingbai,
Liu Shuyang,
Spisak Sarah N.,
Filatov Alexander S.,
Petrukhina Marina A.
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902992
Subject(s) - diglyme , chemistry , crystallography , corannulene , dimer , molecule , ion , solvent , organic chemistry
One‐electron reduction of corannulene, C 20 H 10 , with Li metal in diglyme resulted in crystallization of [{Li + (diglyme) 2 } 4 (C 20 H 10 .− ) 2 (C 20 H 10 ‐C 20 H 10 ) 2− ] ( 1 ), as revealed by single‐crystal X‐ray diffraction. This hybrid product contains two corannulene monoanion‐radicals along with a dianionic dimer, crystallized with four Li + ions wrapped by diglyme molecules. The dimeric (C 20 H 10 ‐C 20 H 10 ) 2− anion provides the first crystallographically confirmed example of spontaneous radical dimerization for C 20 H 10 .− . The C−C bond length between the two C 20 H 10 .− bowls of 1.588(5) Å is consistent with the single σ‐bond character of the linker. The trans ‐disposition of two bowls in the centrosymmetric (C 20 H 10 ‐C 20 H 10 ) 2− dimer is observed with the torsion angle around the central C−C bond of 180°. Comprehensive theoretical analysis of formation/decomposition processes of the dimeric dianion has been carried out in order to evaluate the nature of bonding and energetics of the C 20 H 10 .− coupling. It is found that such σ‐bonded dimers are thermodynamically unstable due to large preparation energy and repulsive Pauli component of the bonding, but kinetically persistent due to a high energy barrier provided by the existing spin‐crossing point.