Have a look at our recent paper entitled “Syntheses, Structures, and Catalytic Investigation of Dicationic Ruthenium(II)-CNC Pincer Complexes with Multiple NHCs Donor Ligands” published in J. Organomet. Chem.
Abstract
We report the reactivity of cationic Ru(II) pincer complexes [Ru(CNCMe)(CNMe)I]PF6 (1a), [Ru(CNCi-Pr)(CNMe)I]PF6 (1b) and [Ru(CNCCy)(CNMe)I]PF6 (1c) with CH3CN and PPh3 ligands and afforded dicationic Ru(II)-CNC pincer complexes namely, [Ru(CNCMe)(CNMe)CH3CN]2PF6 (2a), [Ru(CNCi-Pr)(CNMe)CH3CN]2PF6 (2b), [Ru(CNCCy)(CNMe)CH3CN]2PF6 (2c), [Ru(CNCMe)(CNMe)PPh3]2PF6 (3a), [Ru(CNCi-Pr)(CNMe)PPh3]2PF6 (3b) and [Ru(CNCCy)(CNMe)PPh3]2PF6 (3c). All the new complexes were characterized spectroscopically by multinuclear NMR and HRMS, and molecular structures of complexes 2a and 3a have been determined by the single-crystal X-ray diffraction technique. The structures and electronic properties of all complexes are probed through UV–vis and electrochemical investigations for a comparison of ancillary ligand effects. Investigation of the catalytic activity of new complexes towards nitrile hydration reveals that the reaction proceeds through a common Ru-OH intermediate generated by removal of the I−, CH3CN, or PPh3 ligands, and I− based catalysts (1a–c) are more active than those with CH3CN (2a–c) and PPh3 (3a–c) ligands.