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Triphenylphosphine‐Functionalized Core‐Cross‐Linked Micelles and Nanogels with a Polycationic Outer Shell: Synthesis and Application in Rhodium‐Catalyzed Biphasic Hydrogenations
Author(s) -
Wang Hui,
Vendrame Lorenzo,
Fliedel Christophe,
Chen Si,
Gayet Florence,
D'Agosto Franck,
Lansalot Muriel,
Manoury Eric,
Poli Rinaldo
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202004689
Subject(s) - polymer chemistry , comonomer , chemistry , copolymer , styrene , micelle , polystyrene , polymerization , monomer , catalysis , chain transfer , ethylene glycol , solvent , polymer , aqueous solution , organic chemistry , radical polymerization
Abstract Unimolecular amphiphilic nanoreactors with a poly(4‐vinyl‐ N ‐methylpyridinium iodide) (P4VPMe + I − ) polycationic outer shell and two different architectures (core‐cross‐linked micelles, CCM, and nanogels, NG), with narrow size distributions around 130–150 nm in diameter, were synthesized by RAFT polymerization from an R 0 ‐4VPMe + I − 140 ‐ b ‐S 50 ‐SC(S)SPr macroRAFT agent by either chain extension with a long (300 monomer units) hydrophobic polystyrene‐based block followed by cross‐linking with diethylene glycol dimethacrylate (DEGDMA) for the CCM particles, or by simultaneous chain extension and cross‐linking for the NG particles. A core‐anchored triphenylphosphine (TPP) ligand functionality was introduced by using 4‐diphenylphosphinostyrene (DPPS) as a comonomer (5–20 % mol mol −1 ) in the chain extension (for CCM) or chain extension/cross‐linking (for NG) step. The products were directly obtained as stable colloidal dispersions in water (latexes). After loading with [RhCl(COD)] 2 to yield [RhCl(COD)(TPP@CCM)] or [RhCl(COD)(TPP@NG)], respectively, the polymers were used as polymeric nanoreactors in Rh‐catalyzed aqueous biphasic hydrogenation of the model substrates styrene and 1‐octene, either neat (for styrene) or in an organic solvent (toluene or 1‐nonanol). All hydrogenations were rapid (TOF up to 300 h −1 ) at 25 °C and 20 bar of H 2 pressure, the biphasic mixture rapidly decanted at the end of the reaction (<2 min), the Rh loss was negligible (<0.1 ppm in the recovered organic phase), and the catalyst phase could be recycled 10 times without significant loss of catalytic activity.