Synthesis and characterization of 4,7-dimethyl-1,4,7,10,15,18-hexaazabicyclo[8.5.5]octane. Crystal structures of the cryptate and of the first small azacage complexes with six-coordinate lithium geometry

The synthesis and characterization of 4,7-dimethyl-4,7,10,11,15, 18-hexaazabicy-clo[8.5.5]octane () is described. The ligation properties of the macrobicyclic ligand towards alkaline metal cations are considered. The crystalline structures of the ligand and of the first small azacage complexes with six-coordinate lithium geometry, [Li]+[BPh4]−and [Li]+[ClO4]−, are presented.