C-H Activation of the 5-(Pyridine-3-yloxy)isophthalic Acid to Construct Iridium, Rhodium, and Ruthenium Binuclear Metallocyclophanes

Abstract

The multitopic ligand, 5-(pyridine-3-yloxy)isophthalic acid (m-POiPH2, 1), containing two different coordination sites of pyridine and isophthalic acid linked by the C–O–C bond, is prepared. The reaction of 1 with half sandwich complexes of [Cp*Rh(OAc)2] (Cp* = η5-C5Me5), [Cp*Ir(OAc)2], and [(p-cymene)Ru(OAc)2 afford the construction of binuclear metallocyclophanes [(Cp*Ir)2(m-POiP)2] (2), [(Cp*Rh)2(m-POiP)2 (3), and [((p-cymene)Ru)2(m-POiP)2] (4) in high yields. Crystal structures of 2, 3, and 4 illustrate binuclear metallocyclophanes constructed by cyclometallation by ortho-C–H activation and coordination of N-donor with metals which is confirmed by a single crystal X-ray diffraction (SC-XRD). Each metallocyclophanes shows unique packing structure by intermolecular hydrogen bonding; 2 and 3 shows 1D linear chain network, while the packing of 4 presents the 2D sheet.