Tripodal “click” ligands for copper‐catalyzed ATRP

Abstract

A series of tris(R-methyltriazolylmethyl)amines [R ¼ C 6 H 5 (1), 4-FC 6 H 4 (2), 4-MeOC 6 H 4 (3), Fc (4)] were prepared and used as ligands for catalytic ATRP of methyl methacrylate (MMA). Despite a lower activity, the CuBr/4 catalyst promoted relatively well controlled polymerization compared to CuBr/1, as evidenced by narrower polydispersity indices. Meanwhile, no polymerization activity was observed with CuBr/2 and CuBr/3 under the catalytic conditions investigated. The CV measurements of CuBr 2 complexes supported 1 and 4 in DMSO showed E 1/2 values of -0.206 and -0.224 V, respectively, confirming the more electron-rich nature of CuBr/4. Although both CuBr/1 and CuBr/4 catalysts were only partially soluble in several organic solvents used, kinetic studies revealed a pseudo first order linear plot of ln[M] 0 /[M] t versus time. Addition of CuBr 2 into the polymerization systems led to a decrease in polymer polydispersities and the observed rate constants (k obs ).

Unsymmetrical PEG-substituted tris(triazolyl)amines as bi-functional surfactants for copper-catalyzed aerobic oxidation of alcohols in water

“…Given that amine-triazole moieties have been efficiently used in various metal-promoted catalyses, 27,28 the triazole-based a Determined by fluorescence spectroscopy using pyrene as an organic probe. b Determined by dynamic light scattering (DLS) using 5.0 mM concentration of NBBT-500 and NBBT-2000.…”

Trimethylsilyl‐substituted triazole‐based ligand for copper‐mediated single‐electron transfer living radical polymerization of methyl methacrylate

“…Despite the well‐established chemistry of copper‐catalysed azide–alkyne cycloadditon (CuAAC), applications of its 1,2,3‐triazole products as ligands in catalysis are relatively limited . Although previous studies have employed CuAAC in polymer synthesis, only a few examples of copper catalysts supported by 1,2,3‐triazole ligands in radical polymer synthesis are known . In SET‐LRP, ligands are expected to influence the disproportionation equilibrium of Cu I X/L and stabilize the colloidal Cu 0 activator .…”

“…Since the substituents at the triazole ring can be conveniently varied depending on the organic azides and terminal alkynes used, solubility and redox properties of the copper complexes can be systematically tuned and, as a result, polymer properties can be manipulated. Our group has recently reported the use of the tripodal triazole‐based ligands tris(4‐R‐1,2,3‐triazolylmethyl)amine (R = CH 2 Ph (TBTA), CH 2 Fc (TFcTA)) for copper‐catalysed normal ATRP . However, a major drawback of the Cu I Br/TBTA and Cu I Br/TFcTA catalysts is their low solubility in organic solvents, resulting in broad M w / M n values of the resulting polymers.…”

“…30 -36 Although previous studies have employed CuAAC in polymer synthesis, 37 only a few examples of copper catalysts supported by 1,2,3-triazole ligands in radical polymer synthesis are known. 38,39 In SET-LRP, ligands are expected to influence the disproportionation equilibrium of Cu I X/L and stabilize the colloidal Cu 0 activator. 5 Despite these crucial roles, not many N-ligand types have so far been investigated.…”

“…Our group has recently reported the use of the tripodal triazole-based ligands tris(4-R-1,2,3-triazolylmethyl)amine (R = CH 2 Ph (TBTA), CH 2 Fc (TFcTA)) for copper-catalysed normal ATRP. 39 However, a major drawback of the Cu I Br/TBTA and Cu I Br/TFcTA catalysts is their low solubility in organic solvents, resulting in broad M w /M n values of the resulting polymers. To improve catalyst solubility in organic media and to increase the electron-donating ability, the more hydrophobic tripodal tris(4-trimethylsilylmethyl-1,2,3-triazolylmethyl)amine (TTTA) was prepared and evaluated as a support for Cu(II) deactivator in SET-LRP of methyl methacrylate (MMA).…”