Hypodentate ligands: systematic approaches to complexes containing didentate 2,2′:6′,2″-terpyridine (terpy) and the crystal and molecular structures of [Ru(bipy-N,N′) ₂ (terpy-N,N′)][PF ₆ ] ₂ and [Ru(bipy-N,N′) ₂ (bterpy-N,N′)][PF ₆ ] ₂ (bipy = 2,2′-bipyridine, bterpy = 6-bromo-2,2′:6′,2″-terpyridine)

A series of complexes containing hypodentate didentate 2,2′:6′,2″-terpyridine (terpy) ligands of general formula [Ru(L-N,N′)2(terpy-N,N′)]2+[L = 2,2′-bipyridine (bipy) or 1,10-phenanthroline] have been prepared. The complexes [Ru(bipy-N,N′)2(terpy-N,N′)][PF6]2 and [Ru(bipy-N,N′)2(bterpy-N,N′)][PF6]2(bterpy = 6-bromo-2,2′:6′,2″-terpyridine) have been structurally characterised and shown to contain the didentate terpy ligand in the solid state.