Immobilization of a Rhodium Carbene Complex to an Amphiphilic Block Copolymer for Hydroformylation of 1-Octene under Aqueous Two-Phase Conditions

Abstract

We present the first synthesis of an Nheterocyclic carbene (NHC) rhodium catalyst immobilized to an amphiphilic, water-soluble block copolymer support. The resulting macroligand was applied in the hydroformylation of 1-octene under aqueous two-phase conditions in four consecutive cycles and showed high activity up to 2360 h -1 (TOF).

Poly(2‐oxazoline)s based on fatty acids

“…Block copolymers functionalized with a catalytic ruthenium(II) complex were successfully applied for aqueous ring-closing metathesis [61] as well as for the formation of poly(acetylene) latex particles [62]. In addition, a rhodium functionalized block copolymer was prepared and subsequently applied for micellar catalysis of hydrogenation reactions [63], hydroamino-methylation reactions [64] as well as hydroformylations [65,66]. For the latter hydroformylation reactions triphenylphosphine decorated block copolymers were prepared that were subsequently applied for micellar catalysis in a biphasic system, i.e., the micellar catalysts are present in the aqueous phase while the substrate and product are present in the lipophilic phase as depicted in Figure 7.…”

Intramolecular Oxidation of the Alcohol Functionalities in Hydroxyalkyl‐N‐Heterocyclic Carbene Complexes of Iridium and Rhodium

“…The introduction of the alcohol functionality close to the active metal center might help produce the activation of the alcohol through a chelate-assisted process, and the transformed products are forced to remain attached to the metal, thus allowing for their complete characterization and facilitating the study of their reactivity through further subsequent reactions. Although most alcohol-functionalized imidazolium salts afford NHC-alkoxide chelate complexes, [15] some examples are known in which the alcohol functionalities remain untouched [16,17] and can undergo further reactions promoted by the metal center. [17] In this work we describe the reactivity of [{MCp*Cl 2 } 2 ] (M= Ir, Rh) with a series of alcohol-functionalized azolium salts, and the characterization of the reaction products that resulting from the coordination of the NHC ligands to the metal centers and the subsequent activation of the alcohol functionalities.…”

Ammonium‐Salt‐Tagged IMesAuCl Complexes and Their Application in Gold‐Catalyzed Cycloisomerization Reactions in Water

“…[5][6][7] Nevertheless, their application was limited to homogeneous catalysis in organic solvents for more than a decade. Since then, reports about their linkage to water-soluble polymers [8,9] or silica-based surfaces, [9] their introduction into carbohydrates, [10] and their functionalization with hydrophilic groups, such as carboxylate [11,12] or sulfonate, [12] have been reported. [13] The objective of these latter studies was an improved water solubility which would lead to an easier separation of product and catalyst, and ultimately even the opportunity of catalyst recycling.…”