Polymer complexes. LXX. Synthesis, spectroscopic studies, thermal properties and antimicrobial activity of metal(II) polymer complexes: Spectroscopic studies, thermal properties and antimicrobial activity

Synthesis, characterization, biological evaluation and molecular docking of a Schiff base ligand and its metal complexes

Condensation of 2,3-diaminopyridine with 2,4-dihyrodybenzaldehyde yielded a 4,4'-[(1E,1 ~ E)-(pyridine-2,3-diyl)bis(azanylylidene)]bis(methanylylidene)bis(benzene-1,3-diol) monobasic tridentate Schiff base ligand (HL) with an ONN donor sequence. Elemental analyses, conductivity tests, magnetic susceptibility data, FT-IR, UV-vis spectra, x-ray diffraction, and mass spectrum data of the ligand and its complexes were used for the characterization of the structures. Computational HF/3-21G calculations were performed to optimize their geometrical structures and assess their HOMO-LUMO energy gaps. The low molar conductance of the complexes indicates that they are not electrolytic. From the spectrophotometric and gravimetric analyses, the complexes (2-4) are in the ratio of 1:2, while complexes (1 & 5) (1:1) metal to ligand. 2,3-Diaminopyridine, 2,4-dihydroxybenzaldehyde, ligand (HL) and its complexes were screened for antibacterial and antifungal activities against some bacterial (Enterococcus faecalis, Salmonella typhi, and Staphylococcus epidermidis) and fungal isolates (Aspergillus flavus, Alternaria solani, and Candida albicans). The result reveals that 2,4-dihyrodybenzaldehyde has the strongest antibacterial activity among the other compounds followed by Mn(II) complex. The antimicrobial activity increases by increasing the compound concentration. To assess the inhibitory impact of ligand and its complexes on binding sites of B. cereus (PDB ID: 1FEZ), S. epidermidis (PDB ID: 3KP7), E. faecalis (PDB ID: 5V5U) and S. typhi (PDB ID: 5V2W) proteins, molecular modeling has been implemented offer a fresh concept for medication design. Molecular docking studies confirmed strong binding interactions between the metal complexes and bacterial proteins, validating their biological potential. These findings demonstrate the promising antimicrobial properties of Schiff base metal complexes, making them potential candidates for pharmaceutical and medicinal applications.

Platinum (II) complex of isopentyl glycine ligand: DNA binding, molecular dynamic, and anticancer activity against breast cancer

In this paper, we performed thorough experimental and theoretical calculations to examine the interaction between Pt derivative, as an anticancer, and ct-DNA. The mode of DNA binding with [Pt(NH3)2(Isopentylgly)]NO3, where Isopentylgly is Isopentyl glycine, was evaluated by various spectroscopic methods, docking, and molecular dynamics simulation studies. UV-Vis and fluorescence spectroscopic titration results and CD spectra of DNA-drug showed this interaction is via groove binding. Also, thermal stability studies or DNA melting temperature changes (ΔTm), as well as the quenching emissions monitoring proved it. Also, the thermodynamic parameter and binding constant displayed that complex-DNA formation is a spontaneous process, and H-binding and also groove binding were found to be the main forces. Theoretical studies stated [Pt(NH3)2(Isopentylgly)]NO3-DNA formation occurs on C-G center on DNA, along with rising DNA-compound stability. IC50 value against the human breast cell line probably is due to the Isopentyl glycine ligand in the structure of the Pt compound, and it was obtained more than cisplatin and less than carboplatin against the MCF7 cell.Communicated by Ramaswamy H. Sarma.

Polymer complexes. LXXV. Characterization of quinoline polymer complexes as potential bio-active and anti-corrosion agents

The Cu²⁺, Co²⁺, Ni²⁺ and UO₂²⁺ polymer complexes of 5-(2,3-dimethyl-1-phenylpyrazol-5-one azo)-8-hydroxyquinoline (HL) ligand were prepared and characterized. Elemental analyses, IR spectra, X-ray diffraction analysis and thermal analysis studies have been used to confirm the structure of the prepared polymer complexes. The chemical structure of metal chelates commensurate that the ligand acts as a neutral bis(bidentate) by through four sites of coordination (azo dye nitrogen, carbonyl oxygen, phenolic oxygen and hetero nitrogen from pyridine ring). The molecular and electronic structures of the hydrogen bond conformers of HL ligand were optimized theoretically and the quantum chemical parameters were calculated. Elemental analysis data suggested that the polymer complexes have composition of octahedral geometry for all the polymer complexes. Molecular docking of the binding between HL and the receptors of prostate cancer (PDB code 2Q7L Hormone) and the breast cancer (PDB code 1JNX Gene regulation) was studied. The interaction between HL and its polymer complexes with the calf thymus DNA (CT-DNA) was determined by absorption spectra. The antimicrobial activity of HL and its Cu²⁺, Co²⁺, Ni²⁺ and UO₂²⁺ polymer complexes were investigated; only Cu(II) polymer complex (1) was specifically active against Aspergillus niger. It inhibited the fungal sporulation and distorted the fungal mycelia, which became squashed at a concentration of 150 μg/ml; transmission electron microscope (TEM) also showed a deactivation of autophagy in the treated A. niger cells via accumulation of autophagic bodies in vacuoles. The inhibition process of the prepared ligand (HL) against the corrosion of carbon steel in 2 M HCl solution was determined by various methods (weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques) are found to be in reasonable agreement. The mechanism of inhibition in presence of HL in carbon steel corrosion obeys Friendlish adsorption isotherm.

Allyl rhodanine azo dye derivatives: Potential antimicrobials target d-alanyl carrier protein ligase and nucleoside diphosphate kinase

3-Allyl-5-(4-arylazo)-2-thioxothiazolidine-4-one (HL_n ) ligands (where n = 1 to 3) were hypothesized to have antimicrobial activities mediated through inhibition of new antimicrobial targets. The ligands (HL_n ) were synthesized and characterized by infrared (IR) and ¹ H nuclear magnetic resonance (¹ H NMR) spectra. The ligands (HL_n ) were in silico screened to their potential inhibition to models of d-alanyl carrier protein ligase (DltA) (from Bacillus cereus, PDB code 3FCE) and nucleoside diphosphate kinase (NDK) (from Staphylococcus aureus; PDB code 3Q8U). HL₃ ligand has the best energy and mode of binding to both NDK and DltA, even though its binding to DltA was stronger than that to NDK. In antimicrobial activity of HL₃ ligand, morphological and cytological changes in HL₃ -treated bacteria agreed with the in silico results. The HL₃ ligand showed significant antimicrobial activity against B. cereus, S. aureus, and Fusarium oxysporium. The HL₃ -treated bacterial cells appeared malformed and incompletely separated. Its cell walls appeared electron-lucent and ruptured. They contained more mesosomes than normal cells. It was found that the HL₃ ligand represented as a bactericide against B. cereus and S. aureusby blocking target DltA, and may target NDK.

Metallopolymers for advanced sustainable applications

Since the development of metallopolymers, there has been tremendous interest in the applications of this type of materials. The interest in these materials stems from their potential use in industry as catalysts, biomedical agents in healthcare, energy storage and production as well as climate change mitigation. The past two decades have clearly shown exponential growth in the development of many new classes of metallopolymers that address these issues. Today, metallopolymers are considered to be at the forefront for discovering new and sustainable heterogeneous catalysts, therapeutics for drug-resistant diseases, energy storage and photovoltaics, molecular barometers and thermometers, as well as carbon dioxide sequesters. The focus of this review is to highlight the advances in design of metallopolymers with specific sustainable applications.