Lewis Base Complexation, Aggregation, and Reactivity of σ-Organolithiums. Significance of Fractional Reaction Orders in RLi

摘要

On the basis of our results with 1—3, the following suppositions are proffered with regard to R_mLi_m·nLB systems: (1) smaller coordinatively saturated aggregates lose LB more easily, because they contain more LB able to provide assistance; (2) fractional reaction orders of RLi (also observed in LB-free systems) are indicative of aggregate—substrate complexes, those of the coordinatively saturated smaller aggregates reacting faster because of more extensive LB assistance; (3) predissociation of tetramer to dimer could be a prerequisite of complex formation for substrates that are weak donors like TPM, but may not be needed for strong donor substrates.