Micellar catalysis: Polymer bound palladium catalyst for carbon-carbon coupling reactions in water

Abstract

Metallosurfactants, defined here as hydrophobic metal-containing groups embedded in hydrophilic units when dispersed in water, emanate in the formation of metallomicelles. This approach continues to attract great interest for its ability to serve as micellar catalysts for various metal-mediated chemical transformations in water. Indeed, relevant to green chemistry, micellar catalysis plays a preeminent function as a replacement for organic solvents in a variety of chemical reactions. There are several methods for the interaction of metal complexes (catalysts or catalyst precursors) and surfactants for producing micellar aggregates. A very effective manner for achieving this involves the direct bonding of the metal center to the amphiphilic polymeric materials. Herein, we describe the synthesis of a metallosurfactant containing a palladium complex covalently incorporated into a CO 2 -based triblock polycarbonate derived using a dicarboxylic acid chain-transfer agent. This amphiphilic polycarbonate was shown to self-assemble in water to provide uniform and spherical micelles, where the catalytic metal center is located in the hydrophobic portion of the micelle. The resulting metallosurfactant was demonstrated to effectively catalyze carbon–carbon coupling reactions at very low catalyst loadings.

Facile synthesis of polycarbonates from biomass-based eugenol: catalyst optimization for selective copolymerization of CO2 and eugenol to achieve polycarbonates

“…Again, this study was undertaken to illustrate the use of these bio-based eugenol monomers as replacements for petroleum-based monomers in the preparation of amphiphilic polymers for applications in micellar catalysis and biomedicine. 42–46…”

“…Again, this study was undertaken to illustrate the use of these biobased eugenol monomers as replacements for petroleumbased monomers in the preparation of amphiphilic polymers for applications in micellar catalysis and biomedicine. [42][43][44][45][46] Conclusions Herein, we have described several closely related metal complexes as being highly reactive and selective catalysts in the presence of onium salts for the coupling of epoxide monomers derived from the natural product eugenol and carbon dioxide. Nevertheless, we acknowledge the fact that we have not at this stage designed a strategy for making this process truly sustainable by avoiding all petroleum-based reagents.…”

Post-polymerization functionalization of aliphatic polycarbonates using click chemistry

“…Other metallosurfactants which have been synthesized in an analogous manner contain a terpyridine ligand for the binding of various metals, as well as bipyridine palladium complexes for carbon–carbon bond forming processes (Scheme 4c). 48,49…”

“…Other metallosurfactants which have been synthesized in an analogous manner contain a terpyridine ligand for the binding of various metals, as well as bipyridine palladium complexes for carbon-carbon bond forming processes (Scheme 4c). 48,49 Derivatives of the commonly employed cyclohexene oxide (CHO) such as vinyl-cyclohexene oxide (VCHO), cyclohexadiene oxide (CHDO), and limonene oxide (LO) have been frequently used for the synthesis of functional polycarbonates. Parenthetically, it should be noted here that these alicyclic epoxides are very selective for copolymer formation from the coupling of CO 2 and epoxides.…”

Manipulation of Bowl-Shaped Nanoparticles Self-Assembled from a Bipyridine Pendant Containing Homopolymer

“…Bipyridine containing amphiphilic polymers can self-assemble into micelles, vesicles, and perform self-oscillation reactions . For instance, Yoshida et al synthesized a thermoresponsive diblock copolymer poly­(ethylene oxide)- block -poly­( N -isopropylacrylamide- random - N -aminopropylmethylacrylamide) [PEO- b -P­(NIPAAm- r -NAPMAm)] by reversible addition–fragmentation chain transfer (RAFT) polymerization.…”