The First Unambiguous Characterization of a Neutral Phosphorus Ylide–Lithium Complex: Isolation, Structure, and Ab Initio Investigations of [(PhCH2)2NLi · CH2PPh3]2

Abstract

A four‐membered ring of two lithium and two nitrogen atoms is in the central unit of the dimer in the title (1), a complex between an alkali metal and a neutral phosphorus ylide. Surprisingly, this is the first time that such a model complex for the generation of ylides from phosphonium salts and alkali metal bases has been characterized in the solid state. The structure in solution was also determined, and the complexation energies for this and other model complexes were estimated by ab initio calculations. equation image