Ability of strained C atoms to act as an electron donor.

There is a great deal of strain within the propellane and pyramidane hydrocarbon molecules. Quantum chemical calculations evaluate how this strain affects the ability of the bridgehead C atom to act as an electron donor in hydrogen, halogen, chalcogen, pnicogen, and tetrel bonds, despite the absence of a formal C lone pair or C[double bond, length as m-dash]C multiple bond. The strain induces the formation of a substantial region of negative electrostatic potential on this C atom which can attract the σ-hole of an electrophile.