Organometallic ruthenium, rhodium and iridium complexes containing a P-bound thiophene-2-( N-diphenylphosphino)methylamine ligand: Synthesis, molecular structure and catalytic activity

Abstract

Reaction of Ph 2PNHCH 2-C 4H 3S with [Ru(η 6- p-cymene)(μ-Cl)Cl] 2, [Ru(η 6-benzene)(μ-Cl)Cl] 2, [Rh(μ-Cl)(cod)] 2 and [Ir(η 5-C 5Me 5)(μ-Cl)Cl] 2 yields complexes [Ru(Ph 2PNHCH 2-C 4H 3S)(η 6- p-cymene)Cl 2], 1, [Ru(Ph 2PNHCH 2-C 4H 3S)(η 6-benzene)Cl 2], 2, [Rh(Ph 2PNHCH 2-C 4H 3S)(cod)Cl], 3 and [Ir(Ph 2PNHCH 2-C 4H 3S)(η 5-C 5Me 5)Cl 2], 4, respectively. All complexes were isolated from the reaction solution and fully characterized by analytical and spectroscopic methods. The structure of [Ru(Ph 2PNHCH 2-C 4H 3S)(η 6-benzene)Cl 2], 2 was also determined by single crystal X-ray diffraction. 1– 4 are suitable precursors forming highly active catalyst in the transfer hydrogenation of a variety of simple ketones. Notably, the catalysts obtained by using the ruthenium complexes [Ru(Ph 2PNHCH 2-C 4H 3S)(η 6- p-cymene)Cl 2], 1 and [Ru(Ph 2PNHCH 2-C 4H 3S)(η 6-benzene)Cl 2], 2 are much more active in the transfer hydrogenation converting the carbonyls to the corresponding alcohols in 98–99% yields (TOF ≤ 200 h −1) in comparison to analogous rhodium and iridium complexes.