Synthesis, characterization and biological activity of some unsymmetrical Schiff base transition metal complexes

Abstract

In this study, several unsymmetrical Schiff bases and their cobalt and manganese complexes have been synthesized and characterized. The unsymmetrical Schiff bases were prepared from reaction of o-phenylendiamine derivatives with 1-hydroxy-2-acetonaphthone and then the product was reacted with the following aldehydes: salicyaldehyde, 2-hydroxynaphthaldehyde, 2-pyridinecarboxaldehyde and 2-qinolinecarboxaldehyde to produce the desired tetradentate unsymmetrical Schiff base ligands H2SL, H2NL, HPYL and HQN, respectively. Reaction of these ligands with cobalt and manganese salts produced complexes of the general formula [M(SL)], [(NL)], [M(PYL)] and [M(QL)]. All the complexes were characterized by elemental analysis, infrared spectroscopy, UV-visible spectroscopy, electrical conductivity and magnetic susceptibility measurements. The prepared complexes were examined for their anti-bacterial activity using gram-positive and gram-negative pathogens. The following complexes showed strong antibacterial activity against Staphylococcus aureus: MnSL1, MnSL2 and MnSL3. The genotoxic activity of four complexes, which are MnNL1, MnSL1, CoNL1 and CoSL1, were examined using 8-hydroxy-2-deoxy guanosine (8-OHdG) assay in cultured human blood lymphocytes. All examined complexes were found to be genotoxic at examined concentrations (0.1-100 µg/mL), but with variable magnitudes (p < 0.05). The levels of 8-OHdG induced by MnNL1 and MnSL1 were significantly higher than that induced by CoNL1 and CoSL1 ones. In general, the order of mutagenicity of the compounds is MnSL1 > MnNL1 > CoSL1 > CoNL1. In conclusion, some of the prepared complexes showed some biological activities that might be of interest for future research.

Oxidative Stress-Mediated Antibacterial Activity of the Total Flavonoid Extracted from the Agrimonia pilosa Ledeb. in Methicillin-Resistant Staphylococcusaureus (MRSA)

“…The 16S gene was used as the internal standard for the following analysis. The primers of the oxidative stress-related genes (sodA, katA, TrxB, and perR) and 16S gene were showed in the Table [18]. The MRSA ATCC43300 was cultured at 37 • C and shaken at 180 rpm in MHB.…”

Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities

“…In L3 spectra, the C=N quinolinyl ring at 1588 cm −1 blue-shifted to 1591-1592 cm −1 on coordination in the spectra of Q3, Q8, and Q13. Coordination of L2, L3, L4, and L5 to Ag(I) can thus be proposed to be via either N im or N thiazole and N qui donor atoms [34,40,41], while for L1, coordination was via N im , N qui , and N amine donor atoms.…”

Synthesis, Molluscicidaland Antimicrobial Potentialities of Iron Triad Mononuclear Metal Complexes Incorporating Tridentate Asymmetrical Schiff Base Ligands Containing Soft Sulfur Coordinating Atom

“…This charge transfer band is a result of the formation of the coordination bond between the metal ion and the ligands that causes a change in electron distribution between the ligand and the metal ion. The d-d transitions were not observed since they are perturbed by the broad charge transfer transitions [32]. The discussion for each metal complexes is given below.…”