Polyindole-ZnO Nanocomposite: Synthesis, Characterization and Heterogeneous Catalyst for the 3,4-Dihydropyrimidinone Synthesis under Solvent-free Conditions

Abstract

A Polyindole-ZnO nanocomposite particle was synthesized by using a chemical oxidative polymerization method. Synthesized nanocomposite was characterized by UV-Visible, FTIR, SEM, XRD, EDAX and electrical conductivity measurements. The band at ∼3400 cm⁻¹ and 735 cm⁻¹ in FTIR spectra confirmed the polyindole formation. XRD spectral studies exhibits major diffraction in between 30–40° (2θ) indicates the partial crystalline nature of the polyindole-ZnO nanocomposite. SEM image reveals agglomerated granular particulate nature with ZnO embedded in the polyindole matrix. The application of Polyindole-ZnO nanocomposite as a polymer-supported catalyst was studied for the synthesis of one pot multicomponent Biginelli condensation.

Keywords:

• Biginelli condensation
• Catalyst
• Nanocomposite
• Polyindole-ZnO
• Reusability

ACKNOWLEDGMENTS

We thank National Chemical Laboratory, Pune and C-MET for performing analysis like UV, FTIR, XRD, SEM, SAED, and TEM.

Notes

Reaction Conditions: aldehyde (1 mmol), ethylacetoacetate (1 mmol), urea (1.2 mmol), catalyst. Polyindole–ZnO (in solvent-free condition, 0.005 g).

Temp: Reactions carried out in a sonicator bath 45^°C.

Time: for completion of reaction.

Reaction conditions: Reaction conditions: benzaldehyde (1 mmol), ethylacetoacetate (1 mmol), urea (1.2 mmol) and temperature of sonicator bath 45°C,time was 30 min for all reaction cycles.

^a Reaction cycles: polyindole-ZnO catalyst is recovered and reused.

^b Isolated yield.

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