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Catechin mediated green synthesis of Au nanoparticles: Experimental and theoretical approaches to the determination HOMO-LUMO energy gap and reactivity indexes for the (+)-epicatechin (2S, 3S)

Ebrahimian, J ; Sharif University of Technology | 2022

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  1. Type of Document: Article
  2. DOI: 10.1016/j.arabjc.2022.103758
  3. Publisher: Elsevier B.V , 2022
  4. Abstract:
  5. This work suggests a green method for synthesizing Au nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The mechanism of green synthesized AuNPs was examined by molecular electrostatic potential (MEP) calculations. AuNPs were characterized with different techniques such as Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and Transmission electron microscopy (TEM). Electrochemical investigation of modified glassy carbon electrode using AuNPs (AuNPs/GCE) shows that the electronic transmission rate between the modified electrode and [Fe (CN)6]3−/4− increased. Process of oxidation, energy gap, and chemical reactivity indexes of the (+)-epicatechin (2S,3S) were investigated using electrochemical techniques (cyclic voltammetry (CV) and differential pulse voltammetry (DPV) as well as UV–Visible spectroscopy and compared with quantum mechanical calculations. DPV and CV were used to obtain HOMO energies of the (+)-epicatechin (2S,3S), an optical energy gap was obtained from the UV–Vis spectroscopy. Frontier molecular orbitals analysis (FMO) and reactivity indexes such as chemical hardness (ŋ), electrophilicity (ώ), electronic chemical potential (μ), electron acceptor power (ώ+), electron donor power (ώ−) were determined with functional theory (DFT) calculations. In summary, the HOMO energy obtained from the experimental analyses (EHOMO (from DPV) = -5.24 eV, and EHOMO (from CV) = -5.28 eV) has a relative agreement with the HOMO energy calculated by B3LYP/6–31 g (d, p) including the solvent effect (water) (EHOMO (from B3LYP) = -5.75 eV). Also, UV–Vis spectroscopy gives the bandgap energy equal to 4.31 eV, while the 4.13 eV is calculated by TD-DFT-b3lyp/6–31 + g(d). © 2022 The Author(s)
  6. Keywords:
  7. AuNPs ; DFT and TD-DFT calculations ; Electrochemical properties ; Salix aegyptiaca ; Chemical analysis ; Cyclic voltammetry ; Density functional theory ; Energy gap ; Flavonoids ; Fourier transform infrared spectroscopy ; High resolution transmission electron microscopy ; Molecular orbitals ; Phenols ; Solvents ; Synthesis (chemical) ; Au nanoparticle ; Catechin ; Determined with functional theory and TD-determined with functional theory calculation ; Differential pulse voltammetry ; Epicatechin ; Functional theory ; Green synthesis ; Salix aegyptiacum ; Theory calculation ; Gold nanoparticles
  8. Source: Arabian Journal of Chemistry ; Volume 15, Issue 5 , 2022 ; 18785352 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S1878535222000740