Synthesis and characterization of new ruthenium(III) complexes derived from fluoreneamine-based Schiff base ligands and their catalytic activity in transfer hydrogenation of ketones

Abstract

An easy and convenient synthesis of a new series of octahedral ruthenium(III) complexes bearing Schiff base ligands of general formula [RuCl₂(EPh₃)₂(L)] (where E = P, As and L = O,N-donor Schiff bases) has been reported. The composition of all complexes has been unequivocally characterized by spectral (IR, UV-vis, EPR) and ESI-MS techniques. The substituted Schiff base ligands behave as bidentate O,N-donors and coordinate to ruthenium via the phenolic oxygen, the azomethine nitrogen. Complexes 1–6 have been proven to catalyze the transfer hydrogenation of linear, cyclic and aromatic ketones to their corresponding secondary alcohols in the presence of i-PrOH/KOH at 80 °C with conversion up to 99%. The effect of other variables on the transfer hydrogenation reaction such as solvent, base, and catalyst loading is also reported.

Graphical Abstract

Keywords:

• Ruthenium(III)
• Schiff base ligands
• Synthesis
• Characterization
• Transfer hydrogenation

Disclosure statement

No potential conflict of interest was reported by the author(s).