Syntheses, characterization and oxygen evolution reaction (OER) electrocatalytic properties of M(II) based bromo-salophen complexes

Synthesis, characterisation, and anticancer and antioxidant activities of novel complexes of palladium and an organic Schiff-base ligand

“…The analytical data (Table 1) indicate a metal-to-ligand ratio of 1:1 for all the complex systems. The organic ligand was successfully synthesised, as confirmed by the 1 H-and 13 C-NMR spectra [31]. The ligand was then mixed with palladium to form complex 1; according to its 1 H-NMR spectrum, the resonances related to the aromatic protons appear as multiplets in the 6.80-8.90 ppm range.…”

“…The signals related to the ethylene moiety in the ethylenediamine ligand appear as multiplets between 3 and 4 ppm. In the 13 C-NMR spectrum of complex 1, the aliphatic carbon signals appear in the 46.0-62.6 ppm range, and multiple signals related to the aromatic ring carbons appear in the 114-167 ppm range. In the 1 H-NMR spectrum of complex 2, multiplets related to the aromatic protons appear at 5.70-11.50 ppm; in its 13 C-NMR spectrum, the expected aromatic-only carbon signals appear at 120-190 ppm.…”

“…Notably, the free ligand chemical shift at 7.94 ppm (s, 1H, -N=CH-) is shifted to 7.64 ppm in the complexes. Furthermore, 13 C-NMR spectroscopy was used to confirm the formation of the complexes. Coordination to a metal centre often induces changes in the electronic environment around the coordinated atoms, leading to changes in the chemical shifts of the corresponding carbon nuclei in the free ligands and complexes.…”

“…Furthermore, the multiplicity (singlet, doublet, triplet, etc.) and coupling constants observed in the 13 C-NMR spectra of ligands and complexes can provide valuable information. Notably, coordination can alter the spin-spin coupling patterns and coupling constants of nearby carbon atoms, which can aid in identifying the coordination environment.…”

“…Due to their significance in biology and medicine, the metal complexes of ethylenediamine, phenanthroline, and Schiff bases have attracted significant attention [12]. Notably, palladium(II) complexes involving Schiff bases, phosphines, pyridine, ethylenediamine, bipyridine, and 1,10-phenanthroline have attracted much interest because of their numerous antibacterial [13][14][15], antifungal [16][17][18], chemical sensing [19,20], antiviral [6,21,22], and catalytic [17,23,24] applications. They have additionally been applied in the management of several cancers, including Hodgkin's disease.…”