Immortal SET–LRP mediated by Cu(0) wire

Abstract

Cu(0)-wire/Me 6 -TREN is a well established catalyst for living radical polymerization via SET-LRP. Here, it is demonstrated that this polymerization is not just living, but it is in fact the first example of immortal living radical polymerization. The immortality of SET-LRP mediated with Cu(0) wire was demonstrated by attempting, in an unsuccessful way, to irreversible interrupt multiple times the polymerization via exposure to O 2 from air. SET-LRP indeed stopped each time when the reaction mixture was exposed to air. However, the SET-LRP reaction, was restarted each time after resealing the reaction vessel and reestablishing the catalytic cycle with the same Cu(0) wire, to produce the same conversion as in the conventional uninterrupted SET-LRP process. Despite the interruption by O 2 , the reactivated SET-LRP had a good control of molecular weight, molecular weight evolution, and molecular weight distribution, with perfect retention of chain-end fidelity. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48:

Aqueous SET-LRP catalyzed with “in situ” generated Cu(0) demonstrates surface mediated activation and bimolecular termination

“…1,2,26,37,38,47 It is important to mention that from many LRP methods that provide polymers with narrow molecular weight distribution, only SET-LRP generates polymers with both narrow molecular weight distribution and quantitative or near quantitative chain-end functionality. 6,7,[48][49][50][51]57,[71][72][73][74][75][76][77] Narrow molecular weight distribution is an important feature of the polymers prepared by LRP but the most significant structural parameter of these polymers is the quantitative or near quantitative chain-end functionality combined with narrow molecular weight distribution. Chain-end functionality is the major parameter of a polymer that allows the construction of complex architectures such as multiple block copolymers, 64,73,[76][77][78][79] and dendrimers by iterative synthesis.…”

“…42 At the same time as these developments, the list of solvents used in SET-LRP was expanded to other solvents that in combination with aliphatic N-donor ligands, such as tris[(2-dimethylaminoethyl)] amine (Me 6 -TREN) 4,[43][44][45] and tris(2-amino)ethyl amine (TREN) 1,2,4,16,[43][44][45] mediate the disproportionation of Cu(I)X into Cu(II)X 2 and Cu(0). 46 This list includes but is not limited to H 2 O, 10,26,32,38,40,47 DMSO,6,7,12,21,23,40,[48][49][50][51] formamide (DMF), 46,47 dimethyl acetamide (DMAC), 46,47 alcohols, 22,48 fluorinated alcohols, [52][53][54] ethylene carbonate, 46,47 propylene carbonate, 46,47 and different mixtures of solvents with water, 46,47,55 mixtures of two solvents, 46,55 and even blood serum. …”

“…56 Most monomers used in SET-LRP can often mediate this disproportionation but do not always dissolve Cu(II)X 2 limiting its usefulness under certain conditions. 10,46,57 The catalyst most frequently employed in SET-LRP is Cu(0) in the form of powder 2,4,12,58 including powder generated by the disproportionation of Cu(I)X in a large diversity of solvents, 12 wire, 12,64,69 activated wire [59][60][61][62] and tubes. 63,64 Almost all initiators employed in other metal catalyzed LRP such as alkyl halides, 65,66 sulfonyl halides, 33,48,65,[67][68][69] N-halides 2,70 can be used as such or modified to become soluble for SET-LRP in various media including H 2 O.…”

“…3 Subsequently, SET-LRP was expanded to acrylates, [4][5][6][7][8][9][10][11][12][13][14][15][16][17] methacrylates, 8,[18][19][20][21][22][23][24][25] acrylamides, [26][27][28][29][30][31] methacrylamide, 32 acrylonitrile, 33,34 and monomers containing more complex water soluble side groups, such as sugars, 35,36 N-(2-hydroxypropyl) methacrylamide, 32 dimethylacrylamide, 26 N-isopropylacrylamide, 26,[37][38][39] oligo(ethylene oxide) methyl ether acrylate, 40 oligo(ethylene oxide) methyl ether methacrylate, 41 hydroxyethyl acrylate, 10 hydroxyethyl methacrylate 23 and acryloyl morpholine. 42 At the same time as these developments, the list of solvents used in SET-LRP was expanded to other solvents that in combination with aliphatic N-donor ligands, such as tris[(2-dimethylaminoethyl)...…”

Use of Gd powder as catalyst for single electron transfer‐living radical polymerization: Applications for synthesis of high molecular weight polymethyl methacrylate

“…[3][4][5][6][7][8][9][10][11][12][13][14][15] One of the most successful LRP techniques is single electron transfer-living radical polymerization (SET-LRP) which is an intensively developing area of synthetic polymer chemistry. [16][17][18][19][20][21][22][23][24] Recently, much interest has been devoted to SET-LRP as it provides ultrafast polymerization rate, greater monomer diversity, and less stringent reaction conditions. Moreover, This method provides a very simple way to synthesize dendritic macromolecules, 25 mechanophore-linked polymers, [26][27][28][29] core-shell micelles, and vesicles formed from linear and four-arms star diblock copolymers, 30 AB 2 -type amphiphilic block copolymers, 31 and has also been used in tandem with other reactions such as ''click'' reaction, radical addition fragmentation chain-transfer polymerization and nitroxide-radical-coupling.…”