1,3,5,7-adamantanetetrakis(alpha,alpha-diphenylmethyl)tetrayl tetracation: a stable tetrahedrally arrayed tetracation

Reaction between a fluorosulfuric acid and a tetraol precursor results in the formation of 1,3,5,7-adamantanetetrakis(alpha,alpha-diphenylmethyl)tetrayl tetracation. NMR spectra reveals that adamantane maintaineds its tetrahedral symmetry upon ionization. The tetracation, from -80 degree Celsius to -40 degrees Celsius, is stable. Delocalization of positive charge into the phenyl group is essential to compensate for additional charge-charge repulsion.