bm9b01282_si_001.pdf (6.62 MB)
Replacing Cu(II)Br2 with Me6‑TREN in Biphasic Cu(0)/TREN Catalyzed SET-LRP Reveals the Mixed-Ligand Effect
journal contribution
posted on 2019-10-11, 14:49 authored by Xiaojing Feng, Devendra S. Maurya, Nabil Bensabeh, Adrian Moreno, Takahiro Oh, Yuqing Luo, Ja̅nis Lejnieks, Marina Galià, Yoshiko Miura, Michael J. Monteiro, Gerard Lligadas, Virgil PercecThe
mixed-ligand system consisting of tris(2-aminoethyl)amine (TREN)
and tris(2-dimethylaminoethyl)amine (Me6-TREN) during the
Cu(0) wire-catalyzed single electron transfer-living radical polymerization
(SET-LRP) of methyl acrylate (MA) in “programmed” biphasic
mixtures of the dipolar aprotic solvents NMP, DMF, and DMAc with H2O is reported. Kinetic and chain end analysis studies by NMR
and MALDI-TOF before and after thio-bromo “click” reaction
demonstrated that Me6-TREN complements and makes the less
expensive TREN a very efficient ligand in the absence of externally
added Cu(II)Br2. Statistical analysis of the kinetic data
together with control experiments demonstrated that this mixed-ligand
effect enhanced the apparent rate constant of propagation, monomer
conversion, and molecular weight control. The most efficient effect
was observed at a 1/1 molar ratio between these two ligands, suggesting
that in addition to a fast exchange between the two ligands, a new
single dynamic ligand generated by hydrogen bonding may be responsible
for the mixed ligand observed.