The first trimetallic lithium-sodium-potassium complex: Synthesis and crystal structure of a twelve-vertex Li2Na2K2N4O2 cage molecule containing an amide-alkoxide combination

Several molecular complexes containing a mixture of two alkali metals (e.g., lithium−sodium and lithium−potassium) have been characterised by X-ray crystallographic studies over the past decade.1 Here, in this paper, we break new ground in this important area of intermetallic chemistry by reporting the successful synthesis and X-ray crystallographic characterization of an unprecedented trimetallic (lithium−sodium−potassium) formulation. Furthermore, the new complex, [{[PhN(H)]2(t-BuO)LiNaK·(TMEDA)2}2], (1), is closely related to the cocompositions currently employed as “superbases”,2 reagents of boosted deprotonating ability, in organic synthesis. Two recently reported crystal structures regarded to be architectural models for superbases, a carbanion−alkoxide3a and a carbanion−amide3b combination, both contain their two anionic functionalities (C-/RO- and C-/R2N-, respectively) within one ligand. On the other hand, more realistically, 1 contains two distinct types of anionic ligand [amide−alkoxide (R2N-/RO-)]4 as is the case in superbase reagents.2