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Exploring Electronic and Steric Effects on the Insertion and Polymerization Reactivity of Phosphinesulfonato Pd<sup>II</sup> Catalysts

Exploring Electronic and Steric Effects on the Insertion and Polymerization Reactivity of Phosphinesulfonato PdII Catalysts

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NEUWALD, Boris, Laura FALIVENE, Lucia CAPORASO, Luigi CAVALLO, Stefan MECKING, 2013. Exploring Electronic and Steric Effects on the Insertion and Polymerization Reactivity of Phosphinesulfonato PdII Catalysts. In: Chemistry - A European Journal. 19(52), pp. 17773-17788. ISSN 0947-6539. eISSN 1521-3765

@article{Neuwald2013-12-23Explo-26593, title={Exploring Electronic and Steric Effects on the Insertion and Polymerization Reactivity of Phosphinesulfonato PdII Catalysts}, year={2013}, doi={10.1002/chem.201301365}, number={52}, volume={19}, issn={0947-6539}, journal={Chemistry - A European Journal}, pages={17773--17788}, author={Neuwald, Boris and Falivene, Laura and Caporaso, Lucia and Cavallo, Luigi and Mecking, Stefan} }

deposit-license Chemistry - A European Journal ; 19 (2013), 52. - S. 17773–17788 eng Caporaso, Lucia Caporaso, Lucia Neuwald, Boris 2014-02-26T10:42:22Z Neuwald, Boris Cavallo, Luigi Falivene, Laura Exploring Electronic and Steric Effects on the Insertion and Polymerization Reactivity of Phosphinesulfonato Pd<sup>II</sup> Catalysts Thirteen different symmetric and asymmetric phosphinesulfonato palladium complexes ([{(X1-Cl)-μ-M}n], M=Na, Li, 1=X(P^O)PdMe) were prepared (see Figure 1). The solid-state structures of the corresponding pyridine or lutidine complexes were determined for (MeO)21-py, (iPrO)21-lut, (MeO,Me2)1-lut, (MeO)31-lut, CF31-lut, and Ph1-lut. The reactivities of the catalysts X1, obtained after chloride abstraction with AgBF4, toward methyl acrylate (MA) were quantified through determination of the rate constants for the first and the consecutive MA insertion and the analysis of β-H and other decomposition products through NMR spectroscopy. Differences in the homo- and copolymerization of ethylene and MA regarding catalyst activity and stability over time, polymer molecular weight, and polar co-monomer incorporation were investigated. DFT calculations were performed on the main insertion steps for both monomers to rationalize the effect of the ligand substitution patterns on the polymerization behaviors of the complexes. Full analysis of the data revealed that: 1) electron-deficient catalysts polymerize with higher activity, but fast deactivation is also observed; 2) the double ortho-substituted catalysts (MeO)21 and (MeO)31 allow very high degrees of MA incorporation at low MA concentrations in the copolymerization; and 3) steric shielding leads to a pronounced increase in polymer molecular weight in the copolymerization. The catalyst properties induced by a given P-aryl (alkyl) moiety were combined effectively in catalysts with two different non-chelating aryl moieties, such as cHexO/(MeO)21, which led to copolymers with significantly increased molecular weights compared to the prototypical MeO1. Mecking, Stefan Falivene, Laura 2014-02-26T10:42:22Z 2013-12-23 Cavallo, Luigi Mecking, Stefan

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