Treatment of 1,1,3,3-tetraphenylallene with lithium at low temperature in ethereal solvents leads to a dilithium allenide which apparently consists of two equilibrating 2-lithioallyllithium structures 6a. Reduction with sodium leads to an analogous, though less stable, species 6b. Reduction with potassium does not allow detection of the analogous dipotassium allenide 6c. Rather, protonation by solvent yields 1,1,3,3-tetraphenylallylpotassium (2c) which, in the presence of excess potassium, is further reduced to the corresponding trianion 1. The use of 13C-enriched material and 13C-13C coupling constants allows a determination of the structure of the hydrocarbon framework. Even in the trianion, substantial residual π-bond order is evident.
ASJC Scopus subject areas
- Colloid and Surface Chemistry