Half‐sandwich ruthenium‐based versatile catalyst for both alcohol oxidation and catalytic hydrogenation of carbonyl compounds in aqueous media

Abstract

A series of half‐sandwich ruthenium‐based catalysts for both alcohol oxidation and carbonyl compounds hydrogenation have been synthesized through metal‐induced C–H bond activation based on benzothiazole ligands. The neutral ruthenium complexes 1–4 were fully characterized by UV–vis, NMR, IR, and elemental analysis. Molecular structures of complexes 1 and 3 were further confirmed by X‐ray diffraction analysis. All complexes exhibited high activity for the catalytic oxidation of a variety of alcohols with tBuOOH as oxidants to give carbonyl compounds with high yields in water. Moreover, these half‐sandwich complexes also showed high efficiency for the catalytic hydrogenation of carbonyl compounds in a methanol–water mixture. The catalyst could be reused for at least five cycles without any loss of activity. The catalytic system also worked well for various kinds of substrates with either electron‐donating or electron‐withdrawing groups.

Half-Sandwich Ruthenium Complexes with Hydrazone Ligands: Preparation, Structure, and Catalytic Activity in Cyanosilylether Synthesis under an Air Atmosphere

“…The ruthenium metal center was combined with the N, O atoms of the aryl hydrazone ligands to form a five membered chelated ring with a bite angle of approximately 75.0° observed for O(1)–Ru(1)–N(2). The bond distances of Ru–N, Ru–O, and Ru-Cl were very similar in the two complexes and homologous to the average bond length in previously reported Ru­(II) complexes . The ruthenium atoms were π bonded to the p-cymene at an average Ru–C distance of 2.19 Å.…”

“…Half-sandwich transition metal complexes based on different types of ligands have been widely employed in organic transformations such as oxidative cross coupling, catalytic hydrogenation, hydrogen autotransfer, amidation, and nitrile hydration, due to their good stability and high and diverse catalytic activity. However, such kind of complex used for the cyanosilylation reaction is rare .…”

Half-sandwich iridium complexes with hydrazone ligands: preparation, structure, and catalytic synthesis of cyanosilylethers under air

“…The Ir–N (2.12 Å) and Ir–O (2.06 Å) bond lengths are located in the regular range in comparison with the reported analogous complexes. 29 The Ir–Cl bond distance of 2.41 Å is also comparable with that of the analogous complexes. 29 The five-membered chelate ring Ir(1)–N(2)–N(1)–C(1)–O(1) of the iridium complex 1 is almost planar with the dihedral angle of 5.6° between two planes of N(2)–N(1)–C(1)–O(1) and O(1)–Ir(1)–N(2).…”

“…Half-sandwich iridium complexes are a class of organometallic compounds that have been widely used in organic transformation, such as oxidative cross-coupling, catalytic hydrogenation, hydrogen autotransfer, amidation, and nitrile hydration, and play a very important role in metal–organic chemistry. 22–29 However, their application toward cyanosilylation reaction is in its infancy. 30 Acylhydrazone compounds have received tremendous attention in the past decades due to their excellent properties, such as easy synthesis and strong coordination ability of various metal ions.…”

A “one pot” mass spectrometry technique for characterizing solution- and gas-phase photochemical reactions by electrospray mass spectrometry

“…29,30 The use of metal carbonyls as CO-releasing molecules (CORMs) is also a promising area of research in medicinal chemistry. [31][32][33][34][35][36][37] Ruthenium half-sandwich complexes have found particular applications in transfer-hydrogenation and alcohol oxidation catalysis, [38][39][40] C-H bond functionalisation, 41 as well as in cancer phototherapy. 42,43 The CO-releasing properties of metal carbonyl complexes can be tuned to achieve maximum CO photorelease at the required wavelengths by applying the principles of rational design.…”