ABSTRACT
Silica nanoparticles (SiNPs) were chosen as a solid support material for the immobilization of a new Wilkinson's-type catalyst. In a first step, polymer molecules (poly(triphenylphosphine)ethylene (PTPPE); 4-diphenylphosphine styrene as monomer) were grafted onto the silica nanoparticles by surface-initiated photoinferter-mediated polymerization (SI-PIMP). The catalyst was then created by binding rhodium (Rh) to the polymer side chains, with RhCl3â x H2O as a precursor. The triphenylphosphine units and rhodium as Rh(I) provide an environment to form Wilkinson's catalyst-like structures. Employing multinuclear ((31)P, (29)Si, and (13)C) solid-state NMR spectroscopy (SSNMR), the structure of the catalyst bound to the polymer and the intermediates of the grafting reaction have been characterized. Finally, first applications of this catalyst in hydrogenation reactions employing para-enriched hydrogen gas (PHIP experiments) and an assessment of its leaching properties are presented.
Subject(s)
Rhodium/chemistry , Silicon Dioxide/chemistry , Catalysis , Ethylenes/chemistry , Hydrogenation , Magnetic Resonance Spectroscopy , Organophosphorus Compounds/chemistry , Styrene/chemistryABSTRACT
The unsaturated side chain of l-propargylglycine (Pra) was used to study parahydrogen-induced polarization (PHIP) in synthetic oligopeptides. For the first time PHIP-induced NMR signal enhancement was demonstrated using model peptides bearing various functional side chains.
