Tetradentate Palladium(II) Salophen Complexes: Synthesis, Characterization and Catalytic Activities in Copper-Free Sonogashira Coupling Reaction

Abstract

This paper reports the synthesis and characterization of three salophen ligands; 2,2'- and 2,2'-((1E,1'E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene))bis(4-methoxylphenol)[L1OME]. The compounds were prepared from condensation reaction between salicylaldehyde, and its derivatives, with orthophenylenediamine. Their palladium(II) complexes, namely PdL1H, PdL1C and PdL1OME were synthesized through insertion reaction between the ligands with palladium(II) acetate. All compounds were characterized through melting point, elemental analysis, i nfrared spectroscopy, 1 H and 13 C NMR spectroscopy. Palladium(II) complexes were tested as homogenous catalysts in copper-free Sonogashira coupling reaction between iodobenzene and phenylacetylene in DMSO using triethylamine as base with 1.0 mmol% catalyst loading. The most performing catalyst was PdL1OME with 91% conversion followed by PdL1H (83%) and PdL1C (27%).

Controlling the Synthesis of Metal–Organic Framework UiO-67 by Tuning Its Kinetic Driving Force

“…Schematic of synthesis of metal complexes in mixed linker UiO-67-(bpdc-(NH2)2)0.1 MOF, where L may be acetate from the metal acetate salt.MOF-sal forms a square planar complex upon treatment with copper(II) acetate or cobalt(II) acetate, where Cu or Co is coordinated to nitrogen (from H2bpdc-(NH2)2) and oxygen (from the hydroxy group of salicylaldehyde), to form MOF-sal-Cu or MOF-sal-Co (Figure 14). Attempts to synthesize the analogous Pd(II) complex proved difficult, despite a nearly identical complexes being known from the literature [127][128]…”

Synthesis, Structural Characterization, Hirshfeld Surface Analysis, and Antibacterial Study of Pd(II) and Ni(II) Schiff Base Complexes Derived from Aliphatic Diamine

“…Based on the 1 H NMR spectrum of H 2 AD1Me, the phenolic and azomethine protons were observed at 13.79 and 8.33 ppm, respectively. Upon complexation, the peak of the phenolic proton was absent in both spectra of the complexes suggesting the deprotonation of the phenolic proton. , Another key piece of evidence of the complexation of ligands with metals is the slight upfield and downfield shifts of signals of azomethine protons at 7.90 and 9.48 ppm for [Pd­(AD1Me)] and [Ni­(AD1Me)], respectively, denoting a significant shielding and deshielding effect. This shifting was previously observed by Gondia and Sharma (2018) .…”