Abstract
A series of title carbocations was generated and isolated as stable salts. X-ray analyses revealed a preference for an unsymmetric structure in which the bridging hydrogen is localized on one of the two triarylmethane units. NMR spectroscopy showed a similar preference in solution. The bridging hydrogen fluctuates between the two chromophores in solution, and the energy barrier for the H shift is linearly correlated with the C⋯C+ separation determined by X-ray. According to an extrapolation, the energy barrier should decrease when the C⋯C+ separation is less than 2.7 Å, which suggests a new model for isolable pure organic species with a three-center-two-electron bond.
Original language | English |
---|---|
Pages (from-to) | 1033-1044 |
Number of pages | 12 |
Journal | Pure and Applied Chemistry |
Volume | 82 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2010 May 10 |
Externally published | Yes |
Keywords
- Carbocation
- Hydride shift
- Isotope effects
- Neighboring effects
- Three-center bond
- Triarylmethylium
- X-ray structure
ASJC Scopus subject areas
- Chemistry(all)
- Chemical Engineering(all)