Alkali metal complexes of planar pentadentate macrocycles; a unique environment for lithium in the crystal and molecular structure of (LiL1][PF6]{L1= 1,6-dimethyl-1,2,5,6-tetra-aza-[6.0.0](2,6)pyridinophane-2,4-diene}

Abstract

Multinuclear n.m.r. and chemical studies indicate that the planar pentadentate macrocyclic ligands 1,6-dimethyl-1,2,5,6-tetra-aza-[6.0.0]pyridinophane-2,4-diene (L¹) and L²(L²= 17-phenyl-L¹) form complexes with remarkably high stability to aquation with alkali metal cations; the crystal and molecular structure of the complex [LiL¹][PF₆] has been determined, and the metal shown to be in a unique planar pentadentate environment.