6533b82ffe1ef96bd129491f
RESEARCH PRODUCT
How the interplay of different control mechanisms affects the initiator efficiency factor in controlled radical polymerization: An investigation using organometallic MoIII-based catalysts
Sébastien MariaPhilippe RichardRinaldo PoliRinaldo PoliFrançois Stoffelbachsubject
Nitroxide mediated radical polymerizationRadical polymerizationAtom transfer010402 general chemistryPhotochemistry01 natural sciencesBiochemistryOne-electron oxidative additionStyreneInorganic Chemistrychemistry.chemical_compoundLiving free-radical polymerizationPolymer chemistryMaterials ChemistryReversible addition−fragmentation chain-transfer polymerization[CHIM.COOR]Chemical Sciences/Coordination chemistryPhysical and Theoretical ChemistryMethyl acrylateControlled radical polymerizationMolybdenum010405 organic chemistryChemistryAtom-transfer radical-polymerizationOrganic Chemistry[CHIM.CATA]Chemical Sciences/Catalysis0104 chemical sciences[CHIM.POLY]Chemical Sciences/PolymersCobalt-mediated radical polymerizationInitiator efficiency factordescription
International audience; Compound CpMoI2(iPr2dad) (iPr2dad = iPrNdouble bondCHsingle bondCHdouble bondNiPr), obtained by halide exchange from CpMoCl2(iPr2dad) and NaI, has been isolated and characterized by EPR spectroscopy, cyclic voltammetry, and X-ray crystallography. Its action as a catalyst in atom transfer radical polymerization (ATRP) and as a spin trap in organometallic radical polymerization (OMRP) of styrene and methyl acrylate (MA) monomers has been investigated and compared with that of the dichloro analogue. Compound CpMoCl2(iPr2dad) catalyzes the ATRP of styrene and MA with low efficiency factors f (as low as 0.37 for MA and ethyl 2-chloropropionate as initiator), while it irreversibly traps the corresponding growing radical chains under OMRP conditions. On the other hand, compound CpMoI2(iPr2dad) has a greater ATRP catalytic activity than the dichloro analogue and yields f = 1 for MA and ethyl 2-iodopropionate as initiator. Under OMRP conditions, it does not irreversibly trap the growing radical chains. This comparison serves to illustrate the general principle that low initiator efficiency factors, sometimes observed in ATRP, may result from the interplay of the ATRP and OMRP mechanisms, when the latter ones involves an irreversible radical trapping process.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-07-01 |