peri-Interaction between diarylmethyl and diarylmethylium units in 1,8-disubstituted naphthalenes: preference of localized structure for the C–H bridged carbocation

(8-Diarylmethyl-1-naphthyl)bis(4-dimethylaminophenyl)methyliums (aryl=C6H5, 4-IC6H4, and 4-MeOC6H4) were generated by hydride shift from (4-dimethylaminophenyl)methyl group to the diarylmethylium unit at peri-positions of naphthalene. Successful isolation and low-temperature X-ray analysis indicated that they are novel C–H bridged carbocations, which prefer the localized structure with a short contact of C–H⋯C+ rather than the delocalized one with a three-centered-two-electron bond of (C⋯H⋯C)+.