Ruthenium(III) acyl thiourea complex: A catalyst for transfer hydrogenation of nitroarenes

Abstract

The complex of ruthenium (III) ([RuCl2(PPh3)2BTU], 1) was prepared by reacting the acylthiourea ligand with a ruthenium salt ([RuCl2(PPh3)3]), and has been thoroughly characterised using various analytical techniques such as elemental analysis, magnetic susceptibility, UV–Vis, 1H NMR and single-crystal X-ray diffraction. The crystal packing of 1 has been found to be stabilised by intramolecular and intermolecular hydrogen bonding interactions, as well as CH⋅⋅⋅π contacts, namely C9-H9A⋅⋅⋅Cg(5), C12-H12A⋅⋅⋅Cg(4) and C45-H45⋅⋅⋅Cg(3), which play a crucial role in determining the overall supramolecular crystal structure of the compound. Hirshfeld surface analysis and 2D fingerprint analysis of 1 revealed that the compound was stabilised by various intermolecular interactions, including CH⋯C and CH⋯Cl interactions, with intermolecular H⋅⋅⋅H (54.9 %), C⋅⋅⋅H/H⋅⋅⋅C (23.6 %) and Cl⋅⋅⋅H/H⋅⋅⋅Cl (19.0 %) interactions being more prominent than other types of interactions. Furthermore, the conversion of nitroarenes to their corresponding aniline compounds was studied at different time intervals in ethanol at 50 °C in the presence of NaBH4. Examination of different nitro substrates revealed that 1 was a remarkable catalyst for the catalytic reduction of nitroarenes (0.01 mol of catalyst, >99 yield).