Complexation of anthyridine-based ligand L with [(η 6cymene)RuCl 2 ] 2 , [Cp*RhCl 2 ] 2 , and [Cp*IrCl 2 ] 2 yielded a mononuclear complex: [(N,N-L)Ru(η 6 -cymene)Cl]Cl (1), [(N,N-L)Rh(Cp*)Cl]Cl (2), and [(N,N-L)Ir(Cp*)Cl]Cl (3), respectively [L = 5-phenyl-2,8-di-2pyridinylanthyridine]. Upon treatment with (CH 3 CN)PdCl 2 , complexes 1−3 underwent o-metalation to yield heterobimetallic complexes Ru−Pd, Rh−Pd, and Ir−Pd, respectively.Complexes were all characterized by spectroscopic method, and some are further confirmed by X-ray crystallography. Complex Ru−Pd exhibits catalytic activities for the tandem reactions of Suzuki−Miyaura coupling/transfer hydrogenation of pbromoacetophenone with phenylboronic acid in isopropanol, whereas Ir− Pd shows a moderate activity. However, complex Rh−Pd does not behave the same way. Furthermore, catalytic activity of these heterobimetallic complexes toward debromination/transfer hydrogenation of p-bromoacetophenonewas also investigated. The catalytic pathways of these processes were studied and discussed. This study reveals the base used in the reactions plays an important role in the reaction pathway.

Complexation of L [L = 5-phenyl-2,8-di-2-pyridinyl-anthyridine] with [Pd(CH 3 CN) 4 ](BF 4 ) 2 and [Pd(CH 3 CN) 3 Cl](BF 4 ) in a molar ratio of 1:2 rendered the corresponding dinuclear complexes [Pd 2 L (CH 3 CN) 4 ](BF 4 ) 4 (1) and [Pd 2 L (CH 3 CN) 2 Cl 2 ](BF 4 ) 2 ( 2), respectively. However, treatment of L with (COD)PdCl 2 followed by anion exchange yielded a tetranuclear complex [Pd 4 L 3 Cl 4 ](PF 6 ) 4 (4a). Structures of these complexes are characterized by both spectroscopy and X-ray crystallography. Interconversion of these three complexes was studied via the manipulation of stoichiometric ratio of ligand to metal precursor. The catalytic activity of these complexes for carbonylative Suzuki− Miyaura cross-coupling was investigated. Complex 2 shows an excellent catalytic activity on the reaction of aryl iodide with arylboronic acid in the presence of atmospheric pressure of CO to give the corresponding benzophenones.

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