Syntheses and Reactions of Half-Sandwich Iridium, Rhodium, and Ruthenium Metallacycles Containing 4-Pyridyl Dithioether Ligands†Dedicated to Professor Kazuyuki Tatsumi on the occasion of his 60th birthday.

Metallacyclic complexes [Cp*4Ir4(μ-L′)2(μ-L)2](OTf)4 (2a, L′ = 6,11-dioxy-5,12-naphthacenedione (dhnq2−); L = 4-pyridyl dithioether), [Cp*2Rh2(μ-L′)(μ-L)](OTf)2 (3b), and [(p-cymene)2Ru2(μ- L′)(μ-L)](OTf)2 (3c) were obtained by the reactions of Cp*2M2(μ-L′)Cl2 (M = Ir (1a), Rh (1b)) or (p-cymene)2Ru2(μ-L′)Cl2 (1c) with a flexible bipyridine-based ligand (L) in the presence of AgOTf (OTf = CF3SO3). Treatments of tetranuclear complex 2a and binuclear complexes 3b and 3c with [Cp*IrCl]2(OTf)2 or [Cp*RhCl]2(OTf)2 gave the homotrinuclear complexes [Cp*3Ir3(μ-L′)(μ-L)Cl](OTf)3 (4a) and [Cp*3Rh3(μ-L′)(μ-L)Cl](OTf)3 (4b) and heterotrinuclear complexes [Cp*3Ir2Rh(μ-L′)(μ-L)Cl](OTf)3 (4c), [Cp*3Rh2Ir(μ-L′)(μ-L)Cl](OTf)3 (4d), [Cp*(p-cymene)2Ru2Ir(μ-L′)(μ-L)Cl](OTf)3 (4e), and [Cp*(p-cymene)2Ru2Rh(μ-L′)(μ-L)Cl](OTf)3 (4f), respectively. The flexible tetranuclear complex 2a exhibited different conformations with different guest solvents. The complexes were characterized by IR, 1H NMR spectroscopy, and elemental analysis. In addition, X-ray structure analyses were performed on ligand L and complexes 2a, 3c, 4a, and 4e.