Reference of 33100-27-5, Children learn through play, and they learn more than adults might expect. Science experiments are a great way to spark their curiosity, get their minds active, and encourage them to do something that doesn’t involve a screen. 33100-27-5, C10H20O5. A document type is Article, introducing its new discovery.
The ligand (L) and halide effects of a series of iron complexes (FeX2 or FeX3, X = Cl, Br)/L supported by carbon (Cp2Fe2(I)(CO)4 > Cp2Fe > Fe(CO)5 > (Ph2PCp)2Fe), nitrogen (phthalocyanine ? bpy ? MeO-bpy ? PMDETA > phen), halide (FeXmY4-m/Bu4N, X, Y = Cl ? Br > I), oxygen (12-crown-4 ? 15-crown-5 ? dibenzo-18-crown-6) and phosphorous (P[Ph(2,4,6-OMe)3]3 > P(t-Bu)3 ? P(n-Bu)3, PPh3, P[Ph(4-CF3)]3, P(C6F5)3) ligands, as well as ligand-free FeX3, were evaluated in the normal, ICAR, and photo-ATRP of butadiene (BD) initiated from bromoesters, alpha,alpha-dichloro-p-xylene, or FeX3 in toluene at 110 C. Good polymerization control was observed in many cases, and two clear trends i.e. P[Ph(OMe)3]3 ? Bu4NX > crown ethers > amines > C-ligands and FeCl2, FeCl3 ? FeBr2, FeBr3 occur consistently across all polymerizations. These effects correlate with the higher stability of the allyl PBD-Cl vs. PBD-Br chain ends and with FeCl3 likely being a better deactivator than FeBr3. Conversely, while basic enough to reduce FeX3, P[Ph(2,4,6-OMe)3]3 is not nucleophilic enough to quaternize PBD-X in the apolar toluene and successfully enables a faster activation/deactivation equilibrium than all other ligands. As such, e.g. N-ATRP with [BD]/[R-Br]/[FeCl3]/P[Ph(2,4,6-OMe)3]3 = 100/1/2/3 affords a linear Mnvs. conversion profile with PDI as low as 1.15-1.2 and a halide chain end functionality (CEF) = 0.65 at up to 50% conversion. While controlled polymerizations occur in photo-ATRP even without ligand and initiator, photoirradiation of catalytic N-ATRP with BD/R-Br/FeCl3/P[Ph(2,4,6-OMe)3]3 = 100/1/0.05/0.15 significantly improves the rate (×10 vs. dark), conversion (up to 70%) and X-CEF (0.9) via the additional initiation afforded by FeX3 photolysis, albeit with a slight PDI increase to ?1.4. Thus, Fe-mediated BD-ATRP is achievable, and the rational selection of the polymerization variables enables minimization of side reactions and the successful synthesis of well-defined PBD with a wide range of molecular weights, narrow PDI and reasonably high X-CEF, suitable for the preparation of e.g. block copolymers.
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