2-Pyran-4-Ylidene Malononitrile Based Conjugated Microporous Polymers as Metal-Free Heterogeneous Photocatalysts for Organic Synthesis

Macromol Rapid Commun. 2024 Jun;45(12):e2400083. doi: 10.1002/marc.202400083. Epub 2024 Apr 4.

Abstract

Photoactive conjugated microporous polymers (CMPs) as heterogeneous photocatalysts provide a sustainable alternative to classical metal-based semiconductor photosensitizers. However, previously reported CMPs are typically synthesized through metal catalyzed coupling reactions, which bears product separation, but also increases the price of materials. Herein, a new type of sp2 carbon linked DCM-CMPs are successfully designed and synthesized by organic base catalyzed Knoevenagel reaction using 2,6-Dimethyl-4H-pyran-4-ylidene-malononitrile and aromatic polyaldehydes as monomers. The new polymers feature inherent porosity, excellent stability, and fully π-conjugated skeleton with broad visible-light absorption. They effectively induce the synthesis of benzimidazole compounds under light irradiation, and exhibit wide substrate adaptability with outstanding recyclability.

Keywords: benzimidazole; conjugated microporous polymers; heterogeneous catalysis; photocatalytic transformation.

MeSH terms

  • Benzimidazoles / chemistry
  • Catalysis
  • Light
  • Molecular Structure
  • Nitriles* / chemistry
  • Particle Size
  • Photochemical Processes*
  • Polymers* / chemical synthesis
  • Polymers* / chemistry
  • Porosity
  • Pyrans / chemical synthesis
  • Pyrans / chemistry
  • Surface Properties

Substances

  • Nitriles
  • Polymers
  • dicyanmethane
  • Pyrans
  • Benzimidazoles