Abstract
A new pair of plladium complexes (Pd4 and Pd5) ligated with constrained N-(5,6,7-trihydroquinolin-8-ylidene)arylamine ligands have been prepared and well characterized by 1H-, 13C-NMR and FTIR spectroscopies as well as elemental analysis. The molecular structure of Pd4 and Pd5 in solid state have also been determined by X-ray diffraction, showing slightly distorted square planar geometry around the palladium metal center. All complexes Pd1–Pd5 are revealed highly efficient catalyst in methyl acrylate (MA) polymerization as well as methyl acrylate/norbornene (MA/NB) copolymerization. In the case of MA polymerization, as high as 98.4% conversion with high molecular weight up to 6282 kg·mol−1 was achieved. Likewise, Pd3 complex has good capability to incorporate about 18% NB content into MA polymer chains. Furthermore, low catalyst loadings (0.002 mol %) of Pd4 or Pd5 are able to efficiently mediate the coupling of haloarenes with styrene affording up to 98% conversion.
Highlights
In order to explore the catalytic potential of palladium complexes, a series of ligands L1–L5 and
In order to explorepalladium the catalytic potential of palladium a series Pd1–Pd3 of ligands
On the basis of these encouraging results, we extended thePd5 scope the reported Pd1–Pd3 complexes copolymerization of methyl acrylate (MA) and
Summary
The abundant chemistry of palladium-based complex catalysts has attracted considerable attention, in the field of C–C bond formation, C–H functionalization, hydrocarbon oxidation, as well as radical insertion and addition reaction in polymerization, indicating that palladium is one of the most catalytically versatile transition metals [1,2,3]. Recent progress in polymerization based on palladium catalysts allows the efficient properties on the resulting polymers: improved thermal stability, superior etch resistance, good copolymerization of polar and nonpolar monomers, the catalyst activity and second monomer insertion adhesion due to the ester groups and a hydrophobic character derived from the C–C backbone [31,32,33]. In view of the aforementioned perspectives and higher efficiency catalysts, many copolymerization of polar and non-polar monomers viz.targeting acrylate and norbornene (NB) is still a great newfangled ligand frameworks have been reported to provide subtle control over the palladium challenge. Instance; Nozaki et al developed newfangled ligand frameworks have been reported to provide subtle control over the palladium a highly efficient organic palladium catalyst framework for copolymerization of polar and nonpolar driven [44].
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