Coordination chemistry of a terpyridine-tris(pyrazolyl) ditopic ligand

Abstract

A new ditopic ligand, 4′-(4-(2,2,2-tris(1H-pyrazol-1-ido)ethoxymethyl)phenyl)-2,2′:6′,2″-terpyridine (pzt), has been prepared and its coordination chemistry studied. Metal ions with a preference for octahedral geometry form ML₂ complexes that are readily isolated and characterised, with the metal ion being bound to the terpyridine sites of both ligands. Other metal ions bind to the terpyridine site of just one ligand. In the case of silver(I), a dinuclear M₂L₂ complex has been isolated in which each silver ion is coordinated to the terpyridine site of one ligand and to a single pyrazolyl donor group from the second ligand. Evidence for binding of metal ions to the tris(pyrazolyl) binding site was obtained by electrospray mass spectrometry and NMR techniques. The free ligand and three metal complexes, including the disilver complex, have been characterised by X-ray crystallographic techniques.