KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Chemical Science Program
KAUST Catalysis Center (KCC)
Permanent link to this recordhttp://hdl.handle.net/10754/630494
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AbstractThe copolymerization of ethylene (E) with allyl ethyl ether (AEE) by [di(2-dianisyl)phosphine-2-yl]benzenesulfonato Pd(II) as a catalyst is investigated by DFT calculations and compared with the copolymerization of E with diallyl ether (DAE). For AEE, both 1,2- and 2,1-monomer insertions lead to a very stable O-Chelate product (a five-membered and a four-membered ring, respectively) that hinders any further ethylene insertion. As for DAE, a first 2,1-insertion (favored by 1.8 kcal mol vs the 1,2-insertion) leads to the four-membered O-Chelate product that easily evolves to the most stable intermediate with the second DAE C=C bond coordinated to the metal promoting the following 1,2-insertion. The 2,1 + 1,2 DAE insertion product, bearing a five-membered cyclic unit, is stabilized by a β-agostic interaction that easily opens in favor of E coordination and insertion. Based on the proposed copolymerization mechanism, the stereochemistry of the E/DAE copolymer is studied and the experimental microstructure explained. Finally, [di(2-anisyl)phosphine-2-yl]benzenesulfon(methyl)amido Pd(II) species showing a greater regioselectivity toward a first DAE 2,1-insertion (Δ ΔG of -3.6 kcal mol) are suggested to be a promising catalyst.
CitationWimmer FP, Caporaso L, Cavallo L, Mecking S, Falivene L (2018) Mechanism of Insertion Polymerization of Allyl Ethers. Macromolecules 51: 4525–4531. Available: http://dx.doi.org/10.1021/acs.macromol.8b00783.
SponsorsF.P.W. thanks the KAUST visiting student research program for funding of his internship at KAUST. Support by the DFG (Me 1388/10-2) is gratefully acknowledged.
PublisherAmerican Chemical Society (ACS)