Intramolecular Methylacridan-Methylacridinium Complexes with a Phenanthrene-4,5-diyl or Related Skeleton: Geometry-Property Relationships in Isolable CH Bridged Carbocations
Bridging the gap: Snapshots of 1,6‐H‐shift precursors indicate that a narrower CH⋅⋅⋅C+ separation (D in the ORTEP diagram) in the title complexes induces faster degenerate rearrangement of 1+. A contact distance of less than 2.7 Å is necessary to realize the organic three‐center two‐electron bond of [CHC]+, as indicated by extrapolation of the X‐ray data.