Isolation and Low-Temperature X-ray Analysis of Intramolecular Triarylmethane−Triarylmethylium Complex: Preference for a C−H-Bridged Unsymmetric Structure Exhibiting a Facile 1,5-Hydride Shift and Charge-Transfer Interaction

The intramolecular triarylmethane−methylium complex with an averaged C2v-symmetry was successfully generated by N-methylation of the acridine−acridan hybrid. Theoretical calculation and VT-NMR analyses in solution indicate the unsymmetric geometry for the three-center bond, which was finally confirmed crystallographically. Significant degree of CT interaction is induced through the very short C−H···C+ contact.