Amphiphilic polymeric nanoreactors containing Rh(i)–NHC complexes for the aqueous biphasic hydrogenation of alkenes

Abstract

A rhodium(i) complex bearing a monodentate N-heterocyclic carbene ligand has been confined into the core of amphiphilic core-crosslinked micelles (CCMs).

Polymeric nanoreactors for catalytic applications

“…), date back to 1970 [49]. Many additional investigations into the preparation, characterization and catalytical applications have followed [43,44,[49][50][51][52][53][54][55][56][57].…”

“…A convergent synthesis of polymeric nanoreactors containing polymerizable Rh I -NHC R complexes [53] was then developed (Scheme 8). TEM images of the resulting Rh-NHC R @CCM nanoreactors with R = Me (5a) and R = Mes (5b) (Figure 10) revealed formation of particles with a broad size distribution (diameter of 123.3 ± 19.2 nm).…”

“…Recycling study of Rh-NHC Mes @CCM 5b (number as in Scheme 8) catalyst in styrene hydrogenation (adapted from[53])…”

Phosphine-Functionalized Core-Crosslinked Micelles and Nanogels with an Anionic Poly(styrenesulfonate) Shell: Synthesis, Rhodium(I) Coordination and Aqueous Biphasic Hydrogenation Catalysis

“…Two different degrees of polymerizations (x = 50, 140) were targeted to probe the effect of the hydrophilic shell thickness on the latex stability. Indeed, while the best charged-shell particles were formed with a high degrees of polymerization (140) for the P(SS − Na + ) [34] and P(4VPMe + I − ) [31] homopolymer blocks, those with a P(MAA-co-PEOMA)-based neutral shell [21] only required a low degree of polymerization (30).…”

“…First generation CCM and NG polymers were built with a neutral hydrophilic shell based on linear chains of randomly copolymerized methacrylic acid (MAA) and poly(ethylene oxide) methyl ether methacrylate (PEOMA), where the PEO chains have an average degree of polymerization of 19, a functionalized polystyrene-based (PSt) core, and diethylene glycol dimethacrylate (DEGDMA) was used as a cross-linker [21][22][23][24][25][26][27][28]. The desired ligand was introduced by copolymerization of a suitably functionalized styrene in the second step, mostly 4-diphenylphosphinostyrene (DPPS), to yield PSt-anchored triphenylphosphine (TPP) functions [21,25], but nanoreactors with other PSt-anchored ligands such as bis(p-methoxyphenyl)phenylphosphine [23], nixantphos [29], and a Rh-coordinated N-heterocyclic carbene [30] have also been developed. After the coordination of suitable pre catalysts, these polymers proved efficient and recyclable in aqueous biphasic 1-octene hydroformylation [21][22][23]25] and in 1-octene and styrene hydrogenation [27].…”