Bonding implications of interatomic distances and ligand orientations in the iminolithium hexamers [LiNC(Ph)But]6 and [LiNC(Ph)NMe2]6: a stacked-ring approach to these and related oligomeric organolithium systems

Abstract

The ligand orientations and Li–N distances in the title compounds show that their µ-₃-imino units NC(Ph)R (R = Bu^t or NMe₂) function as 3-electron ligands, forming one 2-centre LiN bond and one 3-centre Li₂N bond to isosceles triangles of bridged metal atoms, prompting treatment of each hexamer [LiNC(Ph)R]₆ as a pair of stacked cyclic trimers [LiNC(Ph)R]₃; extension of this ring-stacking principle allows many other structures to be rationalised in lithium chemistry and facilitates structural predictions.