Syntheses and structural characterizations of novel mono- and dinuclear iridium hydrido complexes with polydentate nitrogen donor ligands

New five mono- and dinuclear Ir hydrido complexes with polydentate nitrogen ligands, [Ir(H)2(PPh3)2(tptz)]PF6 (1), [Ir2(H)4(PPh3)4(tptz)](PF6)2 · 2H2O (2 · 2H2O), [Ir(H)2(PPh3)2(tppz)]BF4 (3), [Ir2(H)4(PPh3)4(tppz)](BF4)2 (4) and [Ir2(H)4(PPh3)4(bted)](BF4)2 · 6CHCl3 (5 · 6CHCl3), were systematically prepared by the reactions of the precursor Ir hydrido complex [Ir(H)2(PPh3)2(Me2CO)2]X (X=PF6 and BF4) with 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz) and 1,4-bis(2,2′:6′,2″-terpyridine-4′-yl)benzene (bted), and their structures and properties were characterized in the solid state and in solution. Each of the Ir hydrido complexes with polydentate nitrogen ligands crystallographically described a unique coordination mode. Their 1H NMR spectra demonstrated unusual 1H NMR chemical shifts of pyridyl rings that are likely induced by the ring current effect of neighboring ligands.