Synthesis, Structural Characterization of Schiff Base Ligands and Their RuII-p-Cymene Complexes, and Catalytic Activity in the Transfer Hydrogenation of Ketones

In this study, two new Schiff base ligands, (E)-ethyl 2-(2-hydroxybenzylideneamino)-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate (L-1) and (E)-ethyl 2-(2-hydroxy-3-methoxybenzylideneamino)-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate (L-2), and their corresponding RuII complexes, [(LRu)-Ru-1(p-cymene)]Cl center dot 2.5H(2)O (1) and [(LRuCl)-Ru-2(p-cymene)]1.5H(2)O (2), were synthesized. The structures of Schiff bases and their Ru-II-p-cymene complexes were elucidated using microanalysis, magnetic susceptibility, molar conductivity, H-1-NMR, C-13-NMR, FT-IR, UV-Vis, LC-MS, and thermogravimetric analysis techniques. Octahedral structures for the obtained Ru-II-p-cymene complexes were proposed. The catalytic activities of the Ru-II-p-cymene complexes obtained after the characterization processes were investigated by using acetophenone derivatives in the transfer hydrogen reactions. The product conversions obtained as a result of catalytic studies were determined using GC-MS. When 4-bromoacetophenone was used as a substrate in the transfer hydrogen reactions, catalysts 1 and 2 showed good catalytic activity of 93% and 96%. [GRAPHICS] .

Automated summary

In this study, two new Schiff base ligands and their corresponding RuII complexes were synthesized and characterized. The obtained RuII complexes showed good catalytic activity in transfer hydrogen reactions. The structures of the compounds were elucidated using various analytical techniques.