Hexaphenylethane is a hypothetical organic compound consisting of an ethane core with six phenyl substituents. As of 2022, 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 instead. A substituted derivative of hexaphenylethane, hexakis(3,5-di-t-butylphenyl)ethane, has however been prepared. It features a very long central C–C bond at 167 pm (compared to the typical bond length of 154 pm). Attractive London dispersion forces between the t-butyl substituents are believed to be responsible for the stability of this very hindered molecule.
See also Tetraphenylmethane
References
Literature Uchimura, Yasuto; Takeda, Takashi; Katoono, Ryo; Fujiwara, Kenshu; Suzuki, Takanori (2015). "Inside Back Cover: New Insights into the Hexaphenylethane Riddle: Formation of an α,o-Dimer". Angewandte Chemie International Edition. 54 (13): 4125. doi:10.1002/anie.201501649.