Me₆-TREN/TREN Mixed-Ligand Effect During SET-LRP in the Catalytically Active DMSO Revitalizes TREN into an Excellent Ligand

Abstract

A mixed-ligand effect was observed for mixtures of tris(2-dimethylaminoethyl)amine (Me 6 -TREN) with tris(2aminoethyl)amine (TREN) ligands during Cu(0) wire-catalyzed, single-electron transfer-living radical polymerization (SET-LRP) of methyl acrylate (MA) initiated with bis(2-bromopropionyl)ethane (BPE) in DMSO. The external order of reaction of SET-LRP both in the presence of Me 6 -TREN, TREN and of the mixedligand Me 6 -TREN/TREN, in DMSO, demonstrated a catalytic activity for DMSO similar to that reported in the presence of Cu(0) powder. The catalytic activity of DMSO, with close to 100% chain-end functionality, facilitates the much less expensive TREN to act as a very efficient ligand that is competitive with Me 6 -TREN and with the mixed-ligand and revitalizes TREN into an excellent ligand. The highest activity of the mixed-ligand at 1/1 ratio between ligands suggests that in addition to a fast exchange between these two ligands, a new single dynamic ligand stabilized by hydrogen-bonding, may generate these results.

Unraveling the Mechanism and Kinetics of Binding of an LCI‐eGFP‐Polymer for Antifouling Coatings

“…We selected SET‐LRP because it accounts for very fast kinetics and control even for methacrylamide monomers in aqueous media with minimal bimolecular termination. [ 89,90,92 ] The latter is necessary to prevent dimer formation that would obscure the adsorption process, whereas the compatibility with water is necessary to maintain the integrity of the proteins. The polymerization was performed using a hydrazine‐activated copper wire as catalyst, [ 93 ] the LCI‐eGFP‐initiator, and the following ratios of [Monomer]:[CuBr 2 ]:[Me 6 TREN]:[LCI‐eGFP‐initiator] = [ X ]:[0.1]:[0.6]:[1], where X represents the molar ratio of monomer ranging from 300 to 800 (Table S1, Supporting Information).…”

“…[ 76 ] By means of the different amino acids, LCI is capable of exerting a multiplicity of weak interactions (H‐bonding, hydrophobic effect, ionic interactions) that drive its physisorption from aqueous dilute solutions onto highly diverse surfaces including cyclic olefin copolymer, polytetrafluoroethylene, titanium, hair, teeth, leaves, [ 75,77,78 ] as well as polystyrene, polypropylene, stainless steel, gold, and silicon wafer. [ 79–83 ] The antifouling block was based on a hydrophilic polymer (pHPMA) grafted via single electron transfer‐living radical polymerization (SET‐LRP) [ 84–90 ] directly from an initiator linked to a cysteine residue in the eGFP.…”

Toward an Efficient Process for the Cu(0)‐Mediated Synthesis and Chain Extension of Poly(methyl acrylate) Macroinitiator Using PMDETA as Ligand

“…The group of Percec has also recently demonstrated the efficacy of a mixed ligand system for Cu(0)‐mediated MA polymerization, reporting a synergetic promotion of reaction rate with an equimolar ratio of Me 6 TREN and tris(2‐aminoethyl)amine (TREN) while maintaining excellent control of chain growth. [ 20 ]…”

Precise and Accelerated Polymer Synthesis via Mixed-Ligand and Mixed-RAFT Agents

“…In this issue of Chem, 5 Anastasaki and co-workers used a mixed-RAFT agent system inspired, most probably, by the SET-LRP mixed-ligand system of the Percec lab 6,7 to control the polymerization kinetics. Here, the authors mixed one highly reactive RAFT agent (C tr > 10) and one low reactive agent (C tr < 10) at varying ratios to control both the M n and M w /M n for a wide variety of monomers (Figure 1).…”

“…But this is a simple and elegant first step toward this goal. This research, together with the brief discussion from this preview, takes mixed-ligand and now mixed-RAFT catalysis from crosscoupling 8-10 organic reactions to macromolecular synthesis [6][7][8] and most probably via other mixed-reagents, back to organic synthesis. Most remarkable, this closed circle between organic and macromolecular synthesis was accomplished by scientists who followed in Hermann Staudinger footsteps at the University of Freiburg 11 and also on the same university campus where Staudinger pioneered 100 years ago, the field of macromolecular chemistry.…”