New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations

• A series of ruthenium (II) carbonyl complexes were synthesized.
• The new complexes were characterized using elemental and spectral methods.
• Ru(II) complexes admirably catalyze the aldehydes to amide conversion.
• New complexes also effectively catalyze the N-alkylation of amines.
• Catalytic transfer hydrogenation was also done using the new complexes.

Schiff base disulfide ligands (H2L1−6) were synthesized from the condensation of cystamine with salicylaldehyde(H2L1), 5-chlorosalicylaldehyde(H2L2), o-vanillin(H2L3), 2-hydroxyacetophenone(H2L4), 3-methyl-2-hydroxyacetophenone(H2L5), and 2-hydroxy-1-naphthaldehyde(H2L6). H2L1−6 reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L1−6]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV–Vis, NMR (1H and 13C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed.

A series of new ruthenium(II) disulfide bearing Schiff base complexes based on cystamine and 2-hydroxybenzaldehydes/2-acetylbenzaldehydes were synthesized and characterized. The catalytic applications of the new complexes were studied towards the aldehyde to amide conversion, N-alkylation and transfer hydrogenation reactions.Figure optionsDownload as PowerPoint slide