Synthesis of long-chained oligo-α-aminopyridines by tandem Pd-catalyzed cross-coupling aminations and their helical dinuclear complexes

Three novel multidentate long-chained oligo-α-aminopyridine ligands, nonapyridyloctaamine (1, npoa), decapyridylnonaamine (2, dpna), and undecapyridyldecaamine (3, upda) were synthesized successfully by tandem Pd-catalyzed cross-coupling aminations. The helical structures of protonated ligand npoa {4, [H4·npoa](SO3CF3)4} and the related dinuclear complexes 5–10 were synthesized and characterized by X-ray diffractions.