Recent Advancements in Schiff Base Fluorescence Chemosensors for the Detection of Heavy Metal Ions

The Schiff base was first synthesized by Hugo Schiff through the condensation reaction of primary amines with carbonyl compounds (aldehyde or ketone) in 1864. Schiff bases exhibit many structural and electrical characteristics that enable their use in a variety of fields, including medical and chemosensing. Schiff bases generate stable complexes when they bind with different metal ions. Schiff bases are employed as fluorescent turn-on/turn-off chemosensors for the detection of various metal cations, such as Hg2+, Cd2+, Cr3+, Pd2+, and As3+ in various materials due to their outstanding coordination ability. This chapter examines a variety of Schiff bases that are employed in chemosensing procedures for various metal ions (such as divalent and trivalent cations) in various biological, agricultural, and environmental settings

Unraveling the Anticancer Efficacy and Biomolecular Properties of Ru(II)-Arene Complexes of Pyrene-Based Thiosemicarbazone Ligands: A Comprehensive In Silico/In Vitro Exploration

We report the successful synthesis and comprehensive characterization of novel Ru(II)-arene complexes incorporating pyrene-based thiosemicarbazone (TSC) ligands. Utilizing a suite of advanced spectroscopic techniques including ultraviolet–visible (UV–visible), Fourier transform infrared (FT-IR), 1H NMR, 13C NMR, and high-resolution mass spectrometry (HRMS), the intricate structural and electronic nuances of these complexes were elucidated. X-ray crystallographic data unequivocally affirmed the ligands’ preferential coordination through the thionyl sulfur and imine nitrogen moieties with the Ru(II) ion. Rigorous density functional theory (DFT) computations reveal these complexes as exemplary electron donors, concomitantly hinting at their significant bioactive potential. Notably, molecular docking and molecular dynamic simulation studies suggest that they are potential SND1 protein inhibitors, which are essential proteins in the functioning of cancer cells. Furthermore, they have a strong affinity for binding to CT-DNA and bovine serum albumin (BSA), indicating DNA intercalation and a strong protein-binding ability. Intriguingly, the Ru-arene TSC complexes unveiled potent cytotoxic activity against an array of cancerous cell lines─most notably MDA-MB-231 (IC50 = 10.2 ± 0.02 μM), A549 (IC50 = 25.7 ± 0.07 μM), and HeLa (IC50 = 20.7 ± 0.05 μM) for RuP2P emerging as a standout agent

Exploring the anticancer potential of thiadiazole derivatives of substituted thiosemicarbazones formed via copper-mediated cyclization

A couple of N-(4)-morpholine/pyrrolidine-substituted thiosemicarbazones (TSCs) of fluorene-2-carboxaldehyde (FM and FP), and their corresponding thiadiazoles (TDZs) (CFM and CFP), were synthesized and characterized (elemental analysis, ultraviolet–visible [UV–Visible], Fourier transform infrared [FT-IR], nuclear magnetic resonance [NMR; 1H & 13C], high-resolution mass spectrometry [HRMS], and single-crystal X-ray diffraction [SCXRD]) for the evaluation of their anticancer potential. The TDZs were obtained unexpectedly and are possibly formed via single-step metal (copper)-mediated oxidative cyclizations of the TSCs. The synthesized compounds are fairly stable in phosphate buffer at the biological pH of 7.4. The density functional theory [DFT] studies were performed to predict the optimized structures and physicochemical properties of these compounds. The compounds were further subjected to computational and experimental biomolecular investigations in order to evaluate their anticancer activity in detail. CFM had the most potent activity against human breast adenocarcinoma (MCF-7) and human urinary bladder (T24) cancer cells, with IC50 values of 12.00 and 24.80 μM, respectively. In contrast, CFM had negligible cytotoxicity (IC50 = 98.70 μM) against kidney epithelial cells extracted from an African green monkey (Vero) normal cells. This outcome was preferable to that of the widely used medicine Cisplatin. Molecular docking studies were performed with the breast cancer protein “cytochrome P450 1A1” (CYP1A1) and bovine serum albumin (BSA) to predict how effectively the compounds bind to the receptor. The ADMET findings suggest that these compounds have considerable drug-likeness and oral bioavailability. These insights may open the door for additional medical research into the bioactivities of TSCs and TDZs produced from bioactive carbonyl compounds

Host-guest interactions of coumarin-based 1,2-pyrazole using analytical and computational methods: Paper strip-based detection, live cell imaging, logic gates and keypad lock applications

A novel Coumarin-based 1,2-pyrazole, HCPyTSC is synthesised and characterized. The chemosensor has been shown to have efficient colourimetric and fluorescence sensing capabilities for the quick and selective detection of fluoride and copper ions. At 376 and 430 nm, the HCPyTSC exhibits selective sensing for Cu2+ and F− ions. By examining the natural bond orbital (NBO) analysis and the potential energy curve (PES) of the ground state for the function of the C–H bond, it has been determined from the theoretical study at hand that the deprotonation was taken from the ‘CH’ proton of the pyrazole ring. For F− and Cu2+, the HCPyTSC detection limits were 4.62 nM and 15.36 nM, respectively. Similarly, the binding constants (Kb) for F− and Cu2+ ions in acetonitrile medium were found to be 2.06 × 105 M−1 and 1.88 × 105 M−1. Chemosensor HCPyTSC with and without F− and Cu2+ ions have an emission and absorption response that can imitate a variety of logic gates, including the AND, XOR, and OR gates. Additionally, a paper-based sensor strip with the HCPyTSC was created for use in practical, flexible F− sensing applications. The paper-based sensor was more effective in detecting F− than other anions. The effectiveness of HCPyTSC for the selective detection of F− in living cells as well as its cell permeability were examined using live-cell imaging in T24 cells