Synthesis, structural characterization, electrochemistry and catalytic transfer hydrogenation of ruthenium(II) carbonyl complexes containing tridentate benzoylhydrazone ligands

Ruthenium(II) carbonyl complexes designed with arsine and PNO/PNS ligands as catalysts for N-alkylation of amines via hydrogen autotransfer process

“…This is an attractive feature for catalytic systems, as it allows for the systematic development of more active catalysts utilizing rational catalyst design. In this context, several donors such as O, N, C, S and P have been reported to functionalize hydrazones/thiosemicarbazones and showed great catalytic activities in CÀX (X¼ C and N) coupling [7], transfer hydrogenation [8] and aldehyde to amide conversion [9]. Nevertheless, the phosphine-functionalized hydrazone and thiosemicarbazone hybrid ligands are relatively not as much investigated.…”

Synthesis, structural characterization and catalytic transfer hydrogenation of ruthenium(II) carbonyl complexes bearing N,N,O pincer type benzoylhydrazone ligands

“…The interest in ruthenium complexes bearing Schiff bases remains unwavering due to their multi-electron transfer properties, ability to have a wide range of oxidation states and potential catalytic activity [1][2][3][4][5][6]. Aroylhydrazones are Schiff bases that have synthetic flexibility, exhibit amide-imidol tautomerism, have a large number of potential donor atoms and hence display versatility in metal coordination.…”

“…Aroylhydrazones are Schiff bases that have synthetic flexibility, exhibit amide-imidol tautomerism, have a large number of potential donor atoms and hence display versatility in metal coordination. They coordinate to a metal ion through the imine nitrogen atom of the hydrazone moiety and the protonated/deprotonated amide oxygen atom [3,4,7]. The binding capacity of the Schiff base is further increased by having an additional donor atom (usually N or O) in a suitable position for chelation, normally resulting in tricoordination [3,[7][8][9][10][11].…”

“…They coordinate to a metal ion through the imine nitrogen atom of the hydrazone moiety and the protonated/deprotonated amide oxygen atom [3,4,7]. The binding capacity of the Schiff base is further increased by having an additional donor atom (usually N or O) in a suitable position for chelation, normally resulting in tricoordination [3,[7][8][9][10][11]. The mode of coordination depends on the nature of the central metal atom, the type of ligand as well as on the presence of other species capable of competing for coordination sites.…”

“…Among the various metal complexes employed for transfer hydrogenation reactions, ruthenium complexes have a long pedigree as catalysts for homogeneous transfer hydrogenation reactions [15,16]. Ruthenium complexes containing cyclometallated and N-heterocyclic carbene ligands [17,18], pincer ligands [19,20], Schiff base ligands [3,21,22], tripodal ligands [23,24], arene ligands [25,26] and phosphine-or amine-based ligands [27,28] Triphenylphosphine, 2-acetylpyridine, benzoylhydrazide derivatives and the ketones used for the catalysis were obtained from Sigma-Aldrich and were used without further purification.…”