Synthesis, spectroscopic, thermal analyses, biological activity and molecular docking studies on mixed ligand complexes derived from Schiff base ligands and 2,6‐pyridine dicarboxylic acid

M. A Comprehensive Review of the Biological Activities of Medicinal Metal Complexes Synthesized From Quinoline Scaffolds

The compelling attributes of quinoline scaffolds in medicinal compounds have garnered considerable attention from researchers, due to their notable biological efficacy, biocompatibility, and distinctive photophysical properties. Quinoline complexes, in particular, have emerged as significant entities, demonstrating a wide array of medicinal properties, including antibacterial, antifungal, antiviral, anticancer, anthelmintic, anti-HIV, antioxidant, antituberculosis, and antimalarial activities. In addition, they showed promise in photodynamic and neurological studies, along with strong DNA-binding capabilities. In recent years (2010-2023), substantial progress has been made in understanding quinoline complexes. Key aspects such as the lipophilicity, of metal complexes, enzymatic drug degradation factors influencing inhibition, drug performance, disruption of target cell growth, and their impact on DNA have been thoroughly investigated. Researchers have employed advanced methodologies including fluorescent imaging, determination of MIC and IC50 values, hydrodynamic and spectrophotometric techniques, in silico and in vitro studies, and cytotoxicity assessments using the MTT method, to significantly enhance our understanding of these complexes. Recent findings indicated that the interaction of quinoline complexes with viral proteins and their ability to disrupt enzyme-viral DNA relationships have made them powerful therapeutic agents for severe diseases including cancer, AIDS, and coronaviruses, as well as various neurological and microbial infections. It is anticipated that these explorations will lead to effective advancements in therapeutic strategies within modern medicine.

Self-Healing Supramolecular Flexible Network of Zn(II): Exploring Chemo-Responsiveness, Antimicrobial Efficiency, and Variable Microelectronic Device Performances

The Zn(II)-supramolecular metallogel (i.e., Zn-Py) of 2,6-pyridinedicarboxylic acid was prepared through the addition of a metal source and 2,6-pyridinedicarboxylic acid as a low molecular weight gelator. The Zn-Py metallogel encapsulated N,N'-dimethylformamide as gel-immobilized polar aprotic solvent media. The mechanical features of the synthesized metallogel were investigated. The thixotropic behavior of the Zn-Py metallogel was also analyzed. The microscopic feature of the metallogel was imaged through FESEM and TEM studies. The EDS pattern of the metallogel ratified the role of different gel-building chemical constituents. The stimuli responsiveness of the metallogel was also tested. The metallogel-forming mechanistic protocol was visualized through FTIR and ESI mass spectroscopic analyses. The bioeffectiveness, i.e., antimicrobial potency, of Zn-Py was also studied. The antimicrobial efficiency against both Gram +ve and Gram -ve bacteria including Salmonella typhimurium (MTCC 98), Escherichia coli (MTCC 1667), Bacillus cereus (ATCC 13061), Listeria monocytogenes (MTCC 657), and Staphylococcus aureus (MTCC 96) was critically analyzed. The FESEM images of the live bacteria and damaged bacteria due to the action of the metallogel were experimentally investigated. The Zn-Py metallogel was also used to fabricate the heterojunction and Schottky-type photodetectors to show their excellent light-matter interaction and their potentiality as active material in optoelectronics. The electrical parameters of semiconductor diodes such as the p-n junction and Schottky diode fabricated by the synthesized Zn-Py metallogel were investigated. Outcomes of the experimental investigation demonstrated that the tested metallogel effectively showed p-n junction diode parameters, especially with the ideality factor (η) of 1.3 under a dark environment. This fabricated device efficiently depicted a great ON/OFF ratio of 33.4 at a reverse bias voltage of -2 V. The metal-semiconductor-metal (M-S-M) junction-type Schottky barrier diode was also fabricated using the Zn-Py metallogel where the Au/Zn-Py metallogel/Au-based device fabrication strategy was implemented.

Cytotoxicity and mechanism of action of metal complexes: An overview

After the discovery of cisplatin, many metal compounds were investigated for the therapy of diseases, especially cancer. The high therapeutic potential of metal-based compounds is related to the special properties of these compounds, such as their redox activity and ability to target vital biological sites. The overproduction of ROS and the consequent destruction of the membrane potential of mitochondria and/or the DNA helix is one of the known pathways leading to the induction of apoptosis by metal complexes. The apoptosis process can occur via the death receptor pathway and/or the mitochondrial pathway. The expression of Bcl2 proteins and the caspase family play critical roles in these pathways. In addition to apoptosis, autophagy is another process that regulates the suppression or promotion of various cancers through a dual action. On the other hand, the ability to interact with DNA is an important property found in several metal complexes with potent antiproliferative effects against cancer cells. These interactions were classified into two important categories: covalent/coordinated or subtle, and non-coordinated interactions. The anticancer activity of metal complexes is sometimes achieved by the simultaneous combination of several mechanisms. In this review, the anticancer effect of metal complexes is mechanistically discussed by different pathways, and some effective agents on their antiproliferative properties are explained.

Synthesis, spectral (FT-IR, 1H, 13C) studies, and crystal structure of [(2,6-CO2)2C5H3NSnBu2(H2O)]2·CHCl3

Di-n-butyltin(IV) 2,6-pyridinedicarboxylate [(2,6-CO2)2C5H3NSnBu2(H2O)]2·CHCl3, has been synthesized and characterized by elemental analyses, infrared and NMR (1H and 13C) spectroscopy, and single-crystal X-ray diffraction. The title complex crystallizes in the triclinic space group P 1 ‾ $P‾{1}$ ; with a = 9.2330(4), b = 10.4790(5), c = 20.2489(8) Å, α = 89.439(4), β = 87.492(3), γ = 85.888(4)°, V = 1951.96(15) Å3, and Z = 2. In this complex, the 2,6-pyridinedicarboxylate groups are tetradentate, chelating, and bridging ligands for the tin(IV) atoms. NMR spectra showed that the ligands bind to the tin(IV) center in the anionic (COO−) form. In the asymmetric unit of the dimeric complex, the monomer is composed of an n-Bu2Sn unit bonded to one 2,6-pyridinedicarboxylate group through one nitrogen and two oxygen donor atoms. It is also coordinated by a water molecule. In the dimer formed by carboxylate bridging, a trans-heptacoordinated geometry around the tin(IV) atom is established. The chloroform molecule is connected to the dimer by C–H···O contacts. Compound exhibits extended O–H···O and C–H···O hydrogen bonding networks leading to a supramolecular layer topology.