Electron Density and Bonding at Inverted Carbon Atoms: An Experimental Study of a [1.1.1]Propellane Derivative

Synchrotron radiation was required for high-resolution diffraction experiments to determine the electron density and analyze the topology of a new [1.1.1]propellane derivative. A bond path with a bond critical point of significant electron density was found between the “inverted” bridgehead atoms C4⋅⋅⋅C4a (see picture), which is characteristic for a covalent bond; however, no charge accumulation at the bond critical point was seen.