New transition metal complexes of 1‐phenyl‐2‐((quinolin‐2‐ylmethylene)amino)ethan‐1‐ol Schiff base: Spectroscopic, X‐ray, DFT, Hirshfeld surface analysis, biological, and molecular docking studies

Synthesis, Crystal Structure and Antifungal Activity of (E)-1-(4-Methylbenzylidene)-4-(3-Isopropylphenyl) Thiosemicarbazone: Quantum Chemical and Experimental Studies

A novel (E)-1-(4-methylbenzylidene)-4-(3-isopropylphenyl) thiosemicarbazone was synthesized in a one-pot four-step synthetic route. Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonances (NMR), single-crystal X-ray diffraction, and UV-visible absorption spectroscopy were utilized to confirm the successful preparation of the title compound. Single-crystal data indicated that the intramolecular hydrogen bond N(3)-H(3)···N(1) and intermolecular hydrogen bond N(2)-H(2)···S(1) (1 - x, 1 - y, 1 - z) existed in the crystal structure and packing of the title compound. Besides the covalent interaction, the non-covalent weak intramolecular hydrogen bond N(3)-H(3)···N(1) discussed by atoms in molecules (AIM) theory also functioned in maintaining the title compound's crystal structure. The strong intermolecular hydrogen bond N(2)-H(2)···S(1) (1 - x, 1 - y, 1 - z) discussed by Hirshfeld surface analysis played a major role in maintaining the title compound's crystal packing. The local maximum and minimum electrostatic potential of the title compound was predicted by electrostatic potential (ESP) analysis. The UV-visible spectra and HOMO-LUMO analysis revealed that the title compound has a low ΔEHOMO-LUMO energy gap (3.86 eV), which implied its high chemical reactivity due to the easy occurrence of charge transfer interactions within the molecule. Molecular docking and in vitro antifungal assays evidenced that its antifungal activity is comparable to the reported pyrimethanil, indicating its usage as a potential candidate for future antifungal drugs.

Catalyzed syntheses of novel series of spiro thiazolidinone derivatives with nano Fe2O3: spectroscopic, X-ray, Hirshfeld surface, DFT, biological and docking evaluations

Twelve spiro thiazolidinone compounds (A-L) were synthesized via either conventional thermal or ultrasonication techniques using Fe2O3 nanoparticles. The modification of the traditional procedure by using Fe2O3 nanoparticles led to enhancement of the yield of the desired candidates to 78-93% in approximately half reaction time compared with 58-79% without catalyst. The products were fully characterized using different analytical and spectroscopic techniques. The structure of the two derivatives 4-phenyl-1-thia-4-azaspirodecan-3-one (A) and 4-(p-tolyl)-1-thia-4-azaspirodecan-3-one (B) were also determined using single crystal X-ray diffraction and Hirshfeld surface analysis. The two compounds (A and B) were crystallized in the orthorhombic system with Pbca and P212121 space groups, respectively. In addition, the crystal packing of compounds revealed the formation of supramolecular array with a net of intermolecular hydrogen bonding interactions. The energy optimized geometries of some selected derivatives were performed by density functional theory (DFT/B3LYP). The reactivity descriptors were also calculated and correlated with their biological properties. All the reported compounds were screened for antimicrobial inhibitions. The two derivatives, F and J, exhibited the highest levels of bacterial inhibition with an inhibition zone of 10-17 mm. Also, the two derivatives, F and J, displayed the most potent fungal inhibition with an inhibition zone of 15-23 mm. Molecular docking investigations of some selected derivatives were performed using a B-DNA (PDB: 1BNA) as a macromolecular target. Structure and activity relationship of the reported compounds were correlated with the data of antimicrobial activities and the computed reactivity parameters.

Versatile applications of transition metal incorporating quinoline Schiff base metal complexes: An overview

Since the last decade, research on quinoline Schiff base metal complexes has risen substantially due to their versatile applications across many significant fields. Schiff bases are also known as azomethines, aldimines, and imines. Quinoline Schiff base-derived metal complexes are intriguing to study topics. These complexes are employed in biological, analytical, and catalytic fields. Researchers have found that Schiff bases are more biologically active when coordinated with metal ions. Research in the biological sciences has shown that heterocyclic compounds like quinoline and its derivatives are important. Because of their broad spectrum of activity, quinoline derivatives have been discovered to be effective therapeutic agents for various disorders. Even though various classical synthetic pathways mentioned in the literature are still in use, there is an urgent need for a new, more effective method that is safer for the environment, has a higher yield, generates less hazardous waste, and is easier to use. This highlights the critical need for a safe, eco-friendly approach to quinoline scaffold synthesis. This review focuses exclusively on Schiff base metal complexes derived from quinoline, fabricated and studied in the past ten years, and having anticancer, antibacterial, antifungal, antioxidant, antidiabetic, antiproliferative, DNA-intercalation, and cytotoxic activities.