Ruthenium(II) complex catalysts bearing a pyridyl-supported pyrazolyl-imine ligand for transfer hydrogenation of ketones

A new class of hemilabile unsymmetrical 2-(1-arylimino)-6-(pyzazol-1-yl)pyridine ligands and their ruthenium(II) and nickel(II) NNN complexes were synthesized. The Ru(II) complex catalysts have been fully characterized and exhibited good to excellent catalytic activity in the transfer hydrogenation (TH) of ketones in refluxing 2-propanol. These results have demonstrated rare examples of active ruthenium(II) NNN complex catalysts that do not feature a N–H functionality for TH of ketones.

Graphical abstractRuthenium(II) complexes bearing a unsymmetrical 2-(1-arylimino)-6-(pyzazol-1-yl)pyridine ligand exhibited good to excellent catalytic activity in the transfer hydrogenation of ketones in refluxing 2-propanol.Figure optionsDownload full-size imageDownload as PowerPoint slide