Micellar Transfer Hydrogenation Catalysis in Water\nwith Monocarbonyl Ruthenium(II)-poly(vinylphosphonate)-Containing\nPolymers: Achieving Reduction of Biomass-Derived Aldehydes

With the aim to build\na supramolecular organometallic catalyst\nfor transfer hydrogenation (TH) reactions of hydrophobic substrates,\nmicellar architectures of different sizes were obtained using amphiphilic\ndiblock copolymers (BCPs) tethered to a Ru(II) monocarbonyl complex.\nAn end-group functionalization strategy was employed to incorporate\na bipyridyl end-group, used to further coordinate the cationic ruthenium\nfragment, to amphiphilic poly(2-vinylpyridine)-<i>b</i>-poly(diethyl\nvinylphosphonate). Owing to their amphiphilic character, the polymers\nform spherical micelles in water, which were characterized by different\nspectroscopic and analytical methods at different pH values and temperatures.\nThe most suitable core–shell micellar system could level the\ncatalytic activity of the ruthenium complex toward hydrophobic and\nbiomass-derived aldehydes, which could be successfully reduced to\nthe corresponding alcohols in water using potassium formate as a hydride\nsource. Depending on the substrate’s hydrophobicity and concentration,\nthe catalytic activity varied significantly. In addition, the polymer’s\nproperties hardly changed during catalysis, facilitating effective\nrecycling until the third catalytic cycle.