Ligand reactivity in iron( II ) complexes of 4′-(4‴-pyridyl)-2,2′ : 6′,2″-terpyridine

The ligand 4′-(4‴-pyridyl)-2,2′ : 6′,2″-terpyridine (pyterpy) acts as a tridentate ligand in which the 4-pyridyl ring is not co-ordinated in the complex cation [Fe(pyterpy)2]2+; the non-co-ordinated ring reacts with electrophiles to give species in which the charge perturbations are localised to a ‘4,4′-bipyridyl’ fragment.