High-Throughput Evaluation of Atom Transfer Radical Polymerization: Towards a Directed Design and Understanding of Optimal Catalytic Systems
-
Zhang, Huiqi; Marin, Veronica; Fijten, Martin W. M.; Schubert, Ulrich S.
- Abstract:
- High-throughput experimentation (HTE) was successfully applied in atom
transfer radical polymerization (ATRP) of methyl methacrylate (MMA) for the rapid
screening and optimization of different reaction conditions. A library of 108 different
reactions was designed for this purpose, which used four different initiators [ethyl
2-bromoisobutyrate, methyl 2-bromopropionate, (1-bromoethyl)benzene, and p-toluenesulfonyl
chloride], five metal salts (CuBr, CuCl, CuSCN, FeBr2, and FeCl2), and nine
ligands (2,2-bipyridine and its derivatives). The optimal reaction conditions for Cu(I)
halide, CuSCN, and Fe(II) halide-mediated ATRP systems with 2,2-bipyridine and its
4,4-dialkyl-substituted derivatives as ligands were determined. Cu(I)-mediated systems
were better controlled than Fe(II)-mediated ones under the examined conditions.
A bipyridine-type ligand with a critical length of the substituted alkyl group (i.e.,
4,4-dihexyl 2,2-bipyridine) exhibited the best performance in Cu(I)-mediated systems,
and p-toluenesulfonyl chloride and ethyl 2-bromoisobutyrate could effectively initiate
Cu(I)-mediated ATRP of MMA, resulting in polymers with low polydispersities in most
cases. Besides, Cu(I) halide-mediated ATRP with 4,5-dimethyl 2,2-bipyridine as the
ligand and p-toluenesulfonyl chloride as the initiator proved to be better controlled than
those with 4,4-dimethyl 2,2-bipyridine as the ligand, and polymers with much lower
polydispersities were obtained in the former cases. This successful HTE example opens
up a way to significantly accelerate the development of new catalytic systems for ATRP
and to improve the understanding of structure–property relationships of the reaction
systems.
- Year:
- 2004
- Type of Publication:
- Article
- Keywords:
- atom transfer radical polymerization ATRP; high throughput experimentation HTE; catalysis; methyl methacrylate; bipyridine derivatives; structureproperty relation
- Journal:
- Journal of Polymer Science: Part A: Polymer Chemistry
- Volume:
- 42
- Pages:
- 1876 - 1885