Unexpected neutral aza-macrocycle complexes of sodium.

Highly unusual Na(+) complexes with neutral tri- and tetra-amines are isolable in good yield from the reaction of NaBAr(F) with the amine in organic media. Structural characterisation reveals primary Na-N bonding, including an unusual sandwich cation [Na(Me3tacn)2](+), derived from homoleptic N6-coordination via two Me3-tacn ligands, and the distorted 5-coordinate [Na(thf)(Me4cyclam)](+).