Formation and Possible Reactions of Organometallic Intermediates with Active Copper(I) Catalysts in ATRP

Kristin Schröder (1) , Dominik Konkolewicz (1) , Rinaldo Poli (2, 3) , Krzysztof Matyjaszewski (1)

1 CMU - Carnegie Mellon University [Pittsburgh]
2 LCC - Laboratoire de chimie de coordination
3 IUF - Institut universitaire de France

The CuI complex obtained in situ from CuI and tris((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)amine (TPMA*) is currently the most reducing and the most active catalyst for atom transfer radical polymerizations (ATRP). The complex has a high affinity for alkyl halides (ATRP pathway) but also has sufficient affinity toward organic radicals to potentially participate in organometallic-mediated radical polymerization (OMRP). Thus, the radical polymerization of n-butyl acrylate initiated by AIBN (azobisisobutyronitrile) was significantly retarded, and the molecular weights decreased in the presence of the CuI/TPMA* complex. These results suggest the presence of a Cu-mediated termination processes, even after the amount of radicals generated from AIBN exceeded the initial amount of CuI/TPMA*. Nevertheless, in the presence of alkyl bromides, which act as ATRP initiators for acrylates, control was gained through metal-mediated halogen atom transfer, i.e., ATRP, not OMRP.

Mots clés: Catalysts; Alkyls; Radical polymerization; Polymerization; Polymers; Controlled Radical Polymerization; ATRP; Organometallic mediated radical polymerization (OMRP); Catalytic Chain Transfer (CCT); Catalytic Radical Termination (CRT); TPMA

Domaines: Chimie de coordination; Catalyse; Polymères

Kristin Schröder, Dominik Konkolewicz, Rinaldo Poli, Krzysztof Matyjaszewski. Formation and Possible Reactions of Organometallic Intermediates with Active Copper(I) Catalysts in ATRP. Organometallics, 2012, 31 (22), pp.7994-7999. ⟨10.1021/om3006883⟩. ⟨hal-03157764⟩