Magnetic nanoparticle-supported ferrocenylphosphine: a reusable catalyst for hydroformylation of alkene and Mizoroki–Heck olefination

Abstract

We present dopamine (dop) conjugated bis(diphenylphosphino)ferrocenylethylamine (BPPFA) functionalized magnetic nanoparticles (Fe₃O₄). A ferrocene ({η⁵-C₅H₄-PPh₂}Fe{η⁵-C₅H₃-1-PPh₂-2-CH(Me)NH-CH₂-CH₂-4Ph-1,2-OH}) ligand (dop-BPPF) has been prepared by reaction of (1-[1′,2-bis(diphenylphosphino)-ferrocenyl]ethyl acetate) and dopamine hydrochloride to form dop-BPPF, which was characterized by NMR, IR, FTIR, EA and FAB-MS. This ligand was anchored on ultrasmall (6–8 nm) magnetic nanoparticles (MNP) to yield Fe₃O₄@dop-BPPF. The resulting ferrocenylphosphine on magnetic nanoparticles was characterized by SEM, EDS, XRD, TEM, TGA, and VSM. The magnetic nature of the materials was investigated. Fe₃O₄@dop-BPPF exhibits very high catalytic activity for the Pd-catalyzed Mizoroki–Heck reaction and exceptionally high regioselectivity for the Rh-catalyzed hydroformylation reaction with branched aldehydes (up to > 99%). The potential of this Fe₃O₄@dop-BPPF as a reusable catalyst has been studied for the Mizoroki–Heck reaction, and this catalyst was robustly active even after eleven consecutive cycles.