Crystallographic and solution NMR structural analyses of four hexacoordinated gallium(III) complexes based on ligands derived from 6-amino-perhydro-1,4-diazepine.

The crystal structures are reported of four gallium(III) complexes based on two pairs of 6-substituted-6-amino-perhydro-1,4-diazepine ligands, together with a study of their solution structures examined by (1)H and (71)Ga NMR spectroscopy. In each case, the ligand adopts a twisted chair conformation that creates a facial array of the three ligand nitrogen atoms. The coordination geometry about each gallium(III) ion is a slightly distorted octahedron, with the 6-phenyl series being slightly more distorted than the 6-methyl analogues. Pulsed NMR experiments allow solution NMR structures to be assessed, revealing good agreement with the solid-state structures.