Coordination chemistry of di-2-pyridylamine-based bridging heterocyclic ligands: A structural study of coordination polymers and discrete dinuclear complexes

Four new bridging ligands containing two di-2-pyridylamine subunits have been synthesised. The coordination chemistry of these, along with one previously reported ligand, has been investigated through reactions with various silver(I), copper(II) and palladium(II) reactants. Typically, reaction of these ligands with silver(I) salts gave 1-D coordination polymers, within which the ligands act as divergent bridging units, while reaction with copper(II) and palladium(II) precursors provided discrete dinuclear complexes with chelating bidentate subunits. The complexes were characterised by a combination of elemental analysis, NMR spectroscopy and X-ray crystallography. The silver coordination polymers displayed interesting variations in supramolecular architecture, attributed to weak secondary interactions, such as Ag⋯π-bonding.