DMSO, an interesting solvent for copper‐catalyzed living radical polymerization (LRP) mediated by disproportionation, does not exhibit the greatest disproportionation of Cu(I)X into Cu(0) and Cu(II)X2. Under suitable conditions, DMSO provides 100% conversion and absence of termination, facilitating the development of complex‐architecture methodologies by living and immortal polymerizations. The mechanism yielding this level of precision is being investigated. Here we compare Cu(0)‐wire‐catalyzed LRP of methyl acrylate mediated by disproportionating ligands tris(2‐dimethylaminoethyl)amine, Me6‐TREN, tris(2‐aminoethyl)amine, TREN, and Me6‐TREN/TREN = 1/1 in presence of eight disproportionating solvents, some more efficient than DMSO in disproportionation. Unexpectedly, we observed that all solvents increased the rate of polymerization when monomer concentration decreased. This reversed trend from that of conventional LRPs demonstrates catalytic effect for disproportionating solvents. Above a certain concentration, the classic concentration‐rate dependence was observed. The external order of reaction of the apparent rate constant of propagation,
Simple synthetic routes to regioselectively deuterated tris[2‐(dimethylamino)ethyl]amine (Me6TREN) variants are described. Imine formation with formaldehyde‐
- Award ID(s):
- 2000391
- NSF-PAR ID:
- 10394860
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemistrySelect
- Volume:
- 8
- Issue:
- 5
- ISSN:
- 2365-6549
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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For electrochemically mediated atom transfer radical polymerization (eATRP), novel mechanistic insights are formulated based on a two-compartment kinetic Monte Carlo model in which catalyst concentration gradients between a large “bulk” compartment away from the electrode and a very small compartment around the electrode are accounted for to reflect the concept of the Nernst diffusion layer. The mass transport of deactivator catalyst to the electrode and its electrochemical reduction at the electrode are treated separately to enable the model to explicitly distinguish between limitations of mass transport and limitations due to intrinsic chemical reactivity. The model is applied to eATRP of methyl acrylate at 298 K with Cu II Br 2 /Me 6 TREN (Me 6 TREN: tris((2-dimethylamino)ethyl)amine) and eATRP of n -butyl acrylate at 317 K with Cu II Br 2 /TPMA (TPMA: tris(2-pyridylmethyl)amine). Diffusional limitations on termination need to be accounted for to properly reflect the eATRP kinetics and the microstructural properties of the obtained polymers. In most cases, an eATRP with mixed chemical and mass transport control is obtained.more » « less
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