Rhodium-complexed hyperbranched poly(ethyleneimine) and polyamidoamine and their non-covalent immobilization on magnetic nanoparticles

• The preparation of new dendritic catalysts based on hyperbranched polymers is described.
• The dendritic catalysts are immobilized on magnetic nanoparticles via ionic interactions.
• The new catalysts show high activity and selectivity in hydroformylation reactions.

We describe a synthetic strategy for the synthesis and functionalization of hyperbranched poly(ethyleneimine) (H-PEI) and polyamidoamine (H-PAMAM) with phosphine ligands and their non-covalent immobilization on magnetic nanosupports. Treatment of these functionalized hyperbranched polymers with Rh(COD)2BF4 affords polymer-bound Rh(I) complexes that can be utilized in the hydroformylation of alkenes and in one pot hydroformylation-Knoevenagel-hydrogenation reactions. These functionalized hyperbranched polymers are linked to magnetic nanoparticles that are modified with carboxylic acid groups via ionic interactions resulting from the acid-base reactions, and are responsible for facilitating the separation of the polymeric catalysts. These magnetically retrievable polymeric catalysts can be reused for up to four cycles.

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