The inverted bond in [1.1.1]propellane is a charge-shift bond.
Bonded or not bonded? An ab initio valence bond study of [1.1.1]propellane shows that the two bridgehead carbons are linked by a strong and direct sigma bond that is neither classically covalent nor classically ionic, but rather a charge-shift bond, in which the covalent-ionic resonance energy plays the major role. As such, the central bond of [1.1.1]propellane closely resembles the single bond of difluorine.
Wu
Wei
W
State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, P.R. China.
Gu
Junjing
J
Song
Jinshuai
J
Shaik
Sason
S
Hiberty
Philippe C
PC