Sherborne G.J.,University of Leeds |
Chapman M.R.,University of Leeds |
Blacker A.J.,University of Leeds |
Bourne R.A.,University of Leeds |
And 11 more authors.
Journal of the American Chemical Society | Year: 2015
A highly robust immobilized [Cp*IrCl2]2 precatalyst on Wang resin for transfer hydrogenation, which can be recycled up to 30 times, was studied using a novel combination of X-ray absorption spectroscopy (XAS) at Ir L3-edge, Cl K-edge, and K K-edge. These culminate in in situ XAS experiments that link structural changes of the Ir complex with its catalytic activity and its deactivation. Mercury poisoning and "hot filtration" experiments ruled out leached Ir as the active catalyst. Spectroscopic evidence indicates the exchange of one chloride ligand with an alkoxide to generate the active precatalyst. The exchange of the second chloride ligand, however, leads to a potassium alkoxide-iridate species as the deactivated form of this immobilized catalyst. These findings could be widely applicable to the many homogeneous transfer hydrogenation catalysts with Cp*IrCl substructure. © 2015 American Chemical Society.
Lucas S.J.,University of Leeds |
Crossley B.D.,Yorkshire Process Technology Ltd |
Pettman A.J.,Pfizer |
Vassileiou A.D.,Pfizer |
And 3 more authors.
Chemical Communications | Year: 2013
This paper provides a viable, reproducible and robust method for immobilising hydroxyl tethered iridium-rhodium complexes. The materials have been shown to be both effective and recyclable in the process of catalytic transfer hydrogenation with minimal metal leaching. © 2013 The Royal Society of Chemistry.