A Highly Efficient Salen‐Palladium Complex as a Homogeneous Catalyst for the Suzuki–Miyaura Coupling Reaction: DFT, Photoluminescence, and Electrochemical Properties

A Schiff base palladium complex displays an efficient Suzuki-Miyaura coupling reaction under the aerobic condition in an ethanol-water medium. The complex exhibits the blue light emission in the solution state, and the DFT and TD-DFT studies show a good correlation with spectral properties.

Abstract

A mononuclear palladium complex based on N, N -bis(3-ethoxysalicylidene)ethylenediamine(H₂L) ligand and complex were synthesised and characterised using ¹H-NMR, FT-IR and UV–visible spectroscopic techniques. ESI-Mass spectroscopy revels the stoichiometry of the complex as [PdL]. The Thermogravimetric analysis (TGA) indicates that the palladium complex is stable up to 375 °C. The Density Functional Theory (DFT) used to determine the quantum chemical parameters of the ligand and the complex. The HOMO-LUMO energy gap of the palladium complex is found to be 3.346 eV. The simulated UV–visible absorption spectra of ligand and the palladium complex using Time Dependent-Density Functional Theory (TD-DFT) shows close agreement with experimentally obtained absorption spectra. The cyclic voltammetry of the palladium complex displays a one-electron quasi-reversible peak (E_1/2 = −1.284 V) corresponding to Pd(II)/Pd(I) redox cycle. The complex exhibit photoluminescent behavior with blue emission at 485 nm. The palladium complex catalyzes Suzuki coupling reaction with 0.2 mol% catalyst loading in aqueous ethanol resulting in significant product yield of 86–99%.

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