Hexaphenylethane
Hexaphenylethane is a hypothetical organic compound consisting of an ethane core with six phenyl substituents. All attempts at its synthesis have been unsuccessful. The trityl free radical, Ph3C, was originally thought to dimerize to form hexaphenylethane. However, an inspection of the NMR spectrum of this dimer reveals that it is in fact a non-symmetrical species, Gomberg's dimer, rather than hexaphenylethane, due to the severe steric repulsions that hexaphenylethane would experience.
However, a substituted derivative of hexaphenylethane, hexakisethane, has been prepared and features a very long central C–C bond at 167 pm. Attractive London dispersion forces between the t-butyl substituents are believed to be responsible for the stability of this very hindered molecule.Literature
