Geometry Constrained N-(5,6,7-Trihydroquinolin-8-ylidene)arylaminopalladium Dichloride Complexes: Catalytic Behavior toward Methyl Acrylate (MA), Methyl Acrylate-co-Norbornene (MA-co-NB) Polymerization and Heck Coupling

Yanning Zeng; Qaiser Mahmood; Tongling Liang; Wen-Hua Sun

doi:10.3390/molecules21121686

Geometry Constrained N-(5,6,7-Trihydroquinolin-8-ylidene)arylaminopalladium Dichloride Complexes: Catalytic Behavior toward Methyl Acrylate (MA), Methyl Acrylate-co-Norbornene (MA-co-NB) Polymerization and Heck Coupling

Molecules. 2016 Dec 7;21(12):1686. doi: 10.3390/molecules21121686.

Authors

Yanning Zeng^{1

2}, Qaiser Mahmood^{3

4}, Tongling Liang⁵, Wen-Hua Sun^{6

7

8}

Affiliations

¹ Key Laboratory of Engineering Plastics, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. [email protected].
² State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China. [email protected].
³ Key Laboratory of Engineering Plastics, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. [email protected].
⁴ International School, University of Chinese Academy of Sciences, Beijing 100049, China. [email protected].
⁵ Key Laboratory of Engineering Plastics, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. [email protected].
⁶ Key Laboratory of Engineering Plastics, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. [email protected].
⁷ State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China. [email protected].
⁸ International School, University of Chinese Academy of Sciences, Beijing 100049, China. [email protected].

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.

Keywords: Heck coupling; MA/NB copolymerization; constrained ligand framework; homopolymerization of MA; palladium complexes.

MeSH terms

Acrylates / chemistry*
Catalysis
Crystallography, X-Ray
Models, Molecular
Molecular Structure
Norbornanes / chemistry*
Palladium / chemistry*
Polymers / chemistry*
Stereoisomerism
X-Ray Diffraction

Substances

Acrylates
Norbornanes
Polymers
2-norbornene
Palladium
methyl acrylate