Impact of the functionalized tetrazole ring on the electrochemical behavior and biological activities of novel nickel (II) complexes with a series of tetrazole derivatives

Abstract

Six new nickel (II) complexes with a series of tetrazole derivatives functionalized by different substituents {5-(2-(1-Benzyltetrazol-5-yl) phenyl)-2-ethyl-4-methylthiazole (L 1), 1-Benzyl-5-(2-(1methylpyrrol-2-yl)phenyl) tetrazole (L 2), 5-(2-(1-Pivalyltetrazol-5-yl)phenyl)-2-ethyl-4methylthiazole (L 3), 5-(2-(1-Methylpyrrol-2-yl) phenyl)-1-pivalyltetrazole (L 4), 2-Ethyl-4-methyl-5-(2-(1 methyltetrazol-5-yl) phenyl) thiazole (L 5) and 1-Methyl-5-(2-(1-methylpyrrol-2-yl)phenyl) tetrazole (L 6)} have been synthesized and characterized by analytical and spectral methods. The data clearly indicated that the nickel (II) complexes are coordinated to the monodentate tetrazole derivatives via nitrogen (N3) atom of the tetrazole ring. The octahedral geometry is observed for all the complexes. The thermogravimetric analysis revealed the presence of coordinated and hydrated water molecules in the coordination sphere. The DFT calculations performed on both the ligands and the complexes allowed to optimize the structures, the stability and to explain the electrochemical behavior and the biological activities of the nickel (II) complexes. The study of the substituents effects on the redox properties of the ligands and their nickel (II) complexes were discussed via cyclic voltammograms. Electron donating substituents shift the reduction potentials toward negative values, while anodic shift of the oxidation potentials is manifested by the substituents having an electron withdrawing effect. The in vitro antimicrobial activities of the ligands and their corresponding nickel (II) complexes have been evaluated against four bacterial and two fungal strains.

Novel palladium(II) complex derived from mixed ligands of dithizone and triphenylphosphine synthesis, characterization, crystal structure, and DFT study

“…The theoretical values of the HOMO and LUMO orbitals of ligands and their palladium complex are shown in (Figure 2) and Table 3. In the free dithizone ligand, the energy gap between HOMO and LUMO orbitals is 2.546 eV while for triphenylphosphine is 4.889 eV [23]. We can see that the dithizone ligand is less stable and more reactive than the triphenylphosphine ligand.…”

Exploration of novel phenyl mercury tetrazole‐thione complexes: Characterization and investigating the impact of diamine ligands on enhanced hydrogen storage

“…These ligands can exhibit different coordination modes depending on the metal ion and ligand structure. They can act as monodentate ligands, coordinating with the metal through a single nitrogen or sulfur atom, or they can act as bi‐dentate ligands, coordinate with the metal through both the nitrogen and sulfur atoms or as poly‐dentate through the nitrogen and sulfur 11‐20 . Tetrazole‐thione complexes have been investigated for their potential applications in areas such as catalysis, luminescence, magnetism, and biological activity 13‐15 .…”

“…[11][12][13][14][15][16][17][18][19][20] Tetrazole-thione complexes have been investigated for their potential applications in areas such as catalysis, luminescence, magnetism, and biological activity. [13][14][15] Their unique structural and electronic properties make them promising candidates for various technological and biomedical applications. Some tetrazolethione complexes have shown interesting biological activities, including antimicrobial, antitumor, and antifungal properties.…”

Nickel Complexes Bearing ONS Chelating Ligands: A Promising Contender for In Vitro Cytotoxicity Effects on Human Pancreatic Cancer MIA-PaCa-2 Cells

“…Therefore, it is assumed that the death cases due to pancreatic cancer will beat those of breast cancer by 2025 as found in the study of 28 European countries . In the recent past, structurally novel transition metal complexes have found extensive applications for various biological activities due to their importance in improving the human health. − The relevance of nickel for biological applications has improved after its identification as the active center in urease and other enzymes. , There are several nickel­(II) complexes that have been extensively explored for their importance in various biological activities such as antimicrobial, − antiproliferative, antioxidant, − and antibacterial. − …”