Titration Experiments Research Articles

Aromatic Ring-Fused Amidine Based Allosteric Receptors Activated by Guest-Induced π-Conjugation Switching.

Amidine-substituted allosteric receptors 2a and 2b for benzenediols were synthesized. Receptor 2a with five-membered amidines exhibited greater allostericity than the amide-substituted receptor 1, while 2b with six-membered amidines exhibited less allostericity. NMR titration experiments revealed that a significant enthalpic factor was involved in the allostericity of these receptors. X-ray and DFT optimized structures of 2a and 2b revealed that 2a adopted a coplanar conformation with π-conjugation between the amidines and the phenylene ring of the hydrindacene framework, resulting in high allostericity due to inactivation of the initial binding.

Conjugated Polymers Based on Carbazole and Tridentate Ligands as the "On-Off-On" Fluorescent Probes for Detection of Ni (II) Ion and Lysine.

Two novel conjugated polymers (polymer 1 and polymer 2) containing trisheterocyclic systemsand carbazole as the copolymerization unit were synthesized by the Suzuki coupling reaction and characterized using NMR spectroscopy and other methods. 4'-(3,5-Dibromophenyl)-2,2':6',2''-terpyridine and 2,2'-(4-(3,5-dibromophenyl)pyridine-2,6-diyl)dithiazole were used as the recognizing units of the two polymers respectively. The polymers show blue-violet fluorescence when dissolved in THF. The ability of the polymers to identify anions and metal ions was investigated by fluorescence sensing tests. It was found that I- not only quenched the fluorescence but also undergone some redshift. Ni (II) efficiently quenched the fluorescence of the polymers, and polymer 2 recognized Ni2+ with higher specificity. UV-visible absorption titration experiments showed that Ni2+ formed complexes with the polymers. In addition, the formation of complexes between Ni2+ and polymers were used for the detection of amino acids, and it was found that lysine could regenerate the fluorescence of [polymer 1-Ni2+] and [polymer 2-Ni2+] with 99% fluorescence recovery.

On the Replicability of the Thermodynamic Modeling of Spectroscopic Titration Data in the Nickel(II) En System

ABSTRACTCharacterizing complicated solution phase systems in situ requires advanced modeling techniques to capture the intricate balances between the many chemical species. Due to the error inherent in any scientific measurement, a spectrophotometric titration experiment with nickel(II) and ethylenediamine (en) was repeated six times using an autotitrator to test the replicability of the data and the consistency of the resulting thermodynamic model. All six datasets could be modeled very tightly (R2 > 99.9999%) with the following eight complexes: [Ni]2+, [Ni2en]4+, [Nien]2+, [Ni2en3]4+, [Nien2]2+, [Ni2en5]4+, [Nien3]2+, and [Nien6]2+. The logK values for the stepwise associative reactions agree with existing literature values for the majority species ([Nienn = 1–3]2+) and matched expectations for the minority species; 95% confidence intervals for each logK value were determined via bootstrapping, which quantifies the variability in the binding constant value that is supported by a given dataset. The repeated experiments, which could not be successfully concatenated together, demonstrate that replication is crucial to capturing all the variability in the logK values. Conversely, bootstrapped confidence intervals across multiple experiments can be readily combined to generate an appropriate range for an experimentally determined binding constant.

Co(II), Ni(II), and Cu(II) Ternary Complexes With 2,6‐Pyridinedicarboxylic Acid and 2,2′‐Bipyridyl: Synthesis, Characterization, DNA Binding, Photo‐Cleavage, and Antimicrobial Studies

ABSTRACTThe interaction of 2,6‐pyridinedicarboxylicacid (PDA) and 2,2′‐bipyridyl (Bipy) with Co(II), Ni(II), and Cu(II) ions produced new ternary complexes [M (PDA)(Bipy)(H2O)] (M = Co(II), Ni(II), and Cu(II)), which were studied by elemental, spectral (FT‐IR, Mass, UV–Vis), and thermal analysis, and their interaction with Ct‐DNA was thoroughly studied using various methods, including absorption spectroscopy, fluorescence spectroscopy, and viscosity measurements. Spectrophotometric titration and viscosity measurements indicated that all the complexes bind to DNA via the groove mode of binding. The salt‐dependent binding of ternary metal complexes to Ct‐DNA has been studied by a UV–Vis spectrophotometric titration experiment. Furthermore, photocleavage studies were used to examine how the metal complexes interacted with the pBR322 DNA, and the results proved that these compounds have obvious photo cleavage properties. The biological effects were studied by antibacterial activity.

A Turn‐On Fluorescence Probe Based on a New Salamo‐Co (II) Coordination Polymer for Tyrosine Detection and Its Application in Water Samples

ABSTRACTA novel salamo‐Co (II) coordination polymer probe CP was synthesized firstly, and its crystal structure, [Co3(L)2(PTA)(H2O)2]n·4nDMF, was determined by X‐ray diffraction analysis. The probe has a rare aggregation‐induced luminescence enhancement (AIEE) effect. When applied to amino acid detection, it was found to have a high selective recognition of tyrosine. With the increase of tyrosine, the fluorescent strength of the probe was enhanced in a short period of time. In addition, the binding ratio of probe to Tyr was determined by fluorescence titration experiment, and the detection limit LOD of probe CP for Tyr was calculated to be 2.57 × 10−9 M, and the binding constant Ka was 2.96 × 105 M−1. According to UV absorption spectrum, FT‐IR spectra, ESI mass spectrometry, and DFT calculation, it was speculated that Tyr can bind to the probe after adding Tyr into the probe solution, triggering FRET and ICT effects, resulting in increased fluorescence intensity and blue shift, and finally achieving the specific recognition of tyrosine by probe CP. Finally, the practical application of probe CP was studied. Through strip test and real water sample test, it was found that the probe can be used for qualitative and quantitative analysis of tyrosine.

Water-Based Polyurethane Dispersions: A Detailed Analysis of the Particle Charge Using Soft and Hard Particle Model.

Water-based polyurethane dispersions (PUDs) show a characteristic dependency of the electrophoretic mobility on the electrolyte concentration, which can be investigated by hard and soft particle models. For this purpose, additional information can be obtained by determining particle charges and electrostatic potentials. PUDs with different contents of an intrinsic ionic stabilizer and various polyol components were synthesized according to the acetone process. The particle charge was characterized by potentiometric acid-base titration, and the data of the titration curve were fitted assuming multiple functional groups with adaptable acid strengths. To investigate the electrostatic potentials, electrophoretic mobilities were measured as a function of electrolyte concentration and analyzed by soft and hard particle theory. Acid-base titration experiments indicated that not all detected ionic groups are located on the surface but are partly arranged inside the polymer particle, as evidenced by a significant decrease of the corresponding effective dissociation constant. The evaluation of the titration data and the electrokinetic experiments showed that the soft particle model of Ohshima is not suitable to reflect the actual particle charge. In contrast, the hard particle model can describe the measured electrophoretic mobility of the dispersions very well if the relaxation effect is taken into account. The dependency of the corresponding zeta potentials on the electrolyte concentration can be excellently modeled assuming a constant surface potential ψ0 and distance of the shear plane xs. Reasonable results are obtained for both parameters with only minor differences between the PUD series. Nonetheless, the electrokinetic surface charge densities calculated with respect to the surface potential are lower than expected from the titration results. Although our results indicate a more complex charge distribution in a peripheral layer, the hard particle model currently shows the best description of the electrokinetic behavior of the PUDs.

Investigation of cytotoxic indoleninyl-thiobarbiturate zwitterions as DNA targeting agents

A series of indoleninyl-thiobarbiturate zwitterions were synthesized in up to 83 % yields from the Knoevenagel condensation between N-substituted diformyl indolenine and thiobarbiturate. The structures were characterized by spectroscopic methods such as NMR (1H, 13C), FT-IR, high-resolution mass spectrometry (HR-MS) and elemental analysis. However, their physicochemical properties and biological activities remain elusive. Herein, results from in silico ADMET calculations and cytotoxicity predictions suggest that all zwitterions are likely to exhibit a higher bioavailability and more specific cytotoxicity than doxorubicin. The notably high predicted cytotoxicity of 2d and drug-likeness score of 2f may be linked to the position of the fused benzene ring and methoxy groups, respectively. The initial biological assessment of these compounds began with in vitro DNA-binding studies because the treatment of numerous diseases such as cancer and bacterial infections is linked to DNA interactions. Zwitterion 2f demonstrated the most significant spectral change in DNA binding studies, suggesting a possible role of the methoxy group in inducing DNA binding activity. The hypothesis that 2f interacts with DNA through groove binding was confirmed by observations made during salt-back titration and DNA denaturation experiments. It was anticipated that the non-zwitterionic 2f would interact more stably with DNA (PDB code: 453D) at the minor groove than its zwitterionic form based on molecular docking calculations and molecular dynamic (MD) simulations. Additionally, the MTT assay demonstrates that 2f is moderately cytotoxic to the human breast cancer cell line MDA-MD-231, most probably as a result of the previously stated DNA binding mechanisms. Overall, the computational and in vitro data suggest the potential application of 2f as a cytotoxic DNA-targeting agent.

Synthesis and spectroscopic studies of triazole-based macroheterocycles containing eudesmane-type sesquiterpenoid moieties

Chiral recognition is one of the most important and fascinating areas in supramolecular chemistry. Chiral macrocycles, especially chiral macrocyclic hosts, having stable structures, adjustable internal cavities to encapsulate and complexation have been developed during the last decade. Attention has been paid on the synthesis of covalently linked of rigid units on the side chain of macrocycles with active binding motifs. In this study, new synthetic protocols has been developed for preparation of optically active triazole-based macrocyclic compounds in which eudesmane-type sesquiterpene lactones act as pendent moieties by the implementation of the copper(I)-catalyzed azid-alkyne cycloaddition strategies. The described protocols provided mild reaction conditions, high yields and high atom- and step-economy. New macrocycles with hanging dihydroisoalantolactone units, different combinations of heteroatoms, and ring sizes in the range of 16–36 atoms were characterized by NMR and UV–vis spectroscopy and mass spectrometry analysis. The molecular structures and intermolecular interactions of two new macrocyclic compounds were elucidated using single-crystal X-ray crystallography. Upon addition of Mg(II) or Zn(II) cations to these novel ligands, using titration experiments we observed the formation of 1:1 (16:Mg2+) complexes and 1:1 to 2:1 (16:Zn2+) complexes, respectively, according to stoichiometry. The result suggests that dihydriisoalantolactone and triazole units within the molecules formed complexes with Mg (II) and Zn (II) ions in solution.

Deep-Saddle-Shaped Nanographene Induced by Four Heptagons: Efficient Synthesis and Properties.

The construction of multiple heptagonal rings in nanographene is the key step for obtaining exotic carbon nanostructures with a negative curvature and intriguing properties. Herein, a novel saddle-shaped nanographene (1) with four embedded heptagons is synthesized via a highly efficient one-shot Scholl reaction from a predesigned oligophenylene precursor. Notably, a quadruple [6]helicene intermediate was also obtained and isolated by controlling the Scholl reaction conditions. Interestingly, the single crystal structures of 1 display a saddle geometry induced by the four embedded heptagons, resulting in a deep curvature with a width of 16.5 Å and a depth of 8.0 Å. Theoretical calculations at the molecular level suggest a weak antiaromatic character of the heptagons in 1. Remarkably, compound 1 exhibits dual fluorescence from S1 and S2. The deep-saddle-shaped geometry in 1 defines host-guest interactions with fullerenes, which were explored in titration experiments and by theoretical methods. The resulting 1@C60 are stable and are subject to an electron transfer from photoexcited 1 to C60. Our current study underscores the influence of heptagon rings on the photophysical, self-assembly, and electron-donating properties of NGs.

Human CSTF2 RNA Recognition Motif Domain Binds to a U-Rich RNA Sequence through a Multistep Binding Process.

The RNA recognition motif (RRM) is a conserved and ubiquitous RNA-binding domain that plays essential roles in mRNA splicing, polyadenylation, transport, and stability. RRM domains exhibit remarkable diversity in binding partners, interacting with various sequences of single- and double-stranded RNA, despite their small size and compact fold. During pre-mRNA cleavage and polyadenylation, the RRM domain from CSTF2 recognizes U- or G/U-rich RNA sequences downstream from the cleavage and polyadenylation site to regulate the process. Given the importance of alternative cleavage and polyadenylation in increasing the diversity of mRNAs, the exact mechanism of binding of RNA to the RRM of CSTF2 remains unclear, particularly in the absence of a structure of this RRM bound to a native RNA substrate. Here, we performed a series of NMR titration and spin relaxation experiments, which were complemented by paramagnetic relaxation enhancement measurements and rigid-body docking, to characterize the interactions of the CSTF2 RRM with a U-rich ligand. Our results reveal a multistep binding process involving differences in ps-ns time scale dynamics and potential structural changes, particularly in the C-terminalα-helix. These results provide insights into how the CSTF2 RRM domain binds to U-rich RNA ligands and offer a greater understanding for the molecular basis of the regulation of pre-mRNA cleavage and polyadenylation.

A Bis(Acridino)-Crown Ether for Recognizing Oligoamines in Spermine Biosynthesis.

Oligoamines in cellular metabolism carry extremely diverse biological functions (i.e., regulating Ca2+-influx, neuronal nitric oxide synthase, membrane potential, Na+, K+-ATPase activity in synaptosomes, etc.). Furthermore, they also act as longevity agents and have a determinative role in autophagy, cell growth, proliferation, and death, while oligoamines dysregulation is a key in a variety of cancers. However, many of their mechanisms of actions have just begun to be understood. In addition to the numerous biosensing methods, only a very few simple small molecule-based tests are available for their selective but reversible tracking or fluorescent labeling. Motivated by this, we present herein a new fluorescent bis(acridino)-crown ether as a sensor molecule for biogenic oligoamines. The sensor molecule can selectively distinguish oligoamines from aliphatic mono- and diamino-analogues, while showing a reversible 1:2 (host:guest) complexation with a stepwise binding process accompanied by a turn-on fluorescence response. Both computational simulations on molecular docking and regression methods on titration experiments were carried out to reveal the oligoamine-recognition properties of the sensor molecule. The new fluorescent chemosensor molecule has a high potential for molecular-level functional studies on the oligoamine systems in cell processes (cellular uptake, transport, progression in cancers, etc.).

A naphthalimide-based bifunctional fluorescent probe for detecting CN− and alkaline pH and its application in food samples and living cells imaging

Cyanide (CN−), as one of the most deadly toxic substances, has further promoted the development of fluorescent probes for identifying it, but the fluorescent probes capable of simultaneously identifying cyanide and alkaline pH have always been a problem. Herein, we have synthesized a novel bifunctional fluorescent probe NCCQ for detecting CN− and alkaline pH. After the reaction of probe NCCQ with CN−, the fluorescence quenching phenomenon occurred obviously, and the quenching efficiency reached 82.7 %. NCCQ is sensitive to CN− (LOD = 44.5 nm), has good selectivity and excellent anti-interference, and can realize rapid response to CN− (50 s). Due to the uncertainty of CN− addition, we further determined the product structure after CN− addition through theoretical calculation. In alkaline pH environment, the fluorescence intensity was further enhanced and red shifted by 14 nm, and the color changed from cyan to bright green. Through mass spectrometry titration experiment, 1HNMR titration experiment and theoretical calculation, the mechanism of detecting CN− and alkaline pH with NCCQ is fully and multi-dimensionally proved. To our surprise, NCCQ can not only be used to detect CN− in real water samples and food samples, but also be used to make bifunctional fluorescent test strips with good results. Due to its good biocompatibility, NCCQ has been successfully applied to the biological imaging of exogenous CN− in Hela, which further proves its great application potential in the fields of environment, food and biological analysis.

Constructing ESIPT-Capable α-Cyanostilbene Luminogens: Influence of Different Aromatic Substitutions Tethered to H-Acceptor (CH = N) on Photophysical Properties, Cu2+ and Fe3+ Detection.

Herein, two excited-state intramolecular proton transfer (ESIPT)-capable α-cyanostilbene luminogens were synthesized by Schiff base reaction of salicylaldehyde-like α-cyanostilbene candidate with 1-naphthylamine and 3-biphenylamine, respectively. We systematically analyzed their photophysical properties compared with their analogue, and demonstrated that their fluorescence behaviors could be elaborately modulated by different aromatic substitutions tethered to H-acceptor (CH = N). In virtue of the outstanding solid fluorescence, the 3-biphenylamine-decorated fluorophore was applied for monitoring Cu2+/Fe3+ qualitatively on the TLC-based test strip in real time and sensing Cu2+/Fe3+ quantitatively in the THF/H2O medium (fw = 90%, pH = 7.4). When the probe chelated with Cu2+/Fe3+, similar "turn-off" fluorescence signal outputs were triggered. From the fluorescence titration experiments, the detection limits were evaluated as 7.97 × 10- 8 M for Cu2+ and 8.24 × 10- 8 M for Fe3+, and the binding constant (Kα) values of the complexes were found to be 7.80 × 104 M-1 for Cu2+ and 9.06 × 104 M-1 for Fe3+. Job's plots indicated that probe complexed with Cu2+/Fe3+ in a 2:1 binding stoichiometry ratio. Furthermore, the probe was used to accurately quantify the Fe3+ spiked in real water specimens. This study offered a new perspective to construct ESIPT-capable α-cyanostilbene luminogen as the potential luminescent probe.

Enhanced Efficiency of Amide‐Substituted Quinuclidine‐Boranes as Hydridic Hydrogen Atom Transfer Catalysts for Photoinduced Hydroalkylation of Unactivated Olefins†

Comprehensive SummaryAn amide‐substituted quinuclidine‐borane has been identified as a more efficient hydridic hydrogen atom transfer (HAT) catalyst for the hydroalkylation of unactivated olefins under visible‐light irradiation. 1H NMR titration experiments reveal that the amide moiety of the quinuclidine‐borane catalyst forms stronger hydrogen bonds with the carbonyl substrates, thereby improving the reaction yields. Furthermore, it was found that the reaction yields correlate well with the association constant between the quinuclidine‐borane catalyst and the carbonyl substrate. A scale‐up reaction using a continuous‐flow photoreactor has also been demonstrated.

Preferential Binding to a Mannoside of a Pyridine–Acetylene–Phenol Macrocycle with a Fluorine Substituent in the Cavity

We developed a pyridine–acetylene–phenol macrocycle in which a fluorine atom was introduced in place of a hydroxy group, as a host for the selective binding to epimers of glucose. The fluorine atom was expected to work as a negatively charged infill repelling oxygen atoms of saccharides andprevent the efficient formation of a hydrogen‐bond network with a glucoside, whose cross‐section size is larger than those of the corresponding epimers, especially of a mannoside. UV−Vis and fluorescence titration experiments revealed that this host showed a higher affinity for a mannoside than a glucoside. 1H NMR and molecular modeling suggested that the fluorine atom acts as a moderate infill weakening the binding to a glucoside.This result indicates that selectivity for guest molecules can be modified by replacing a hydroxy group and a hydrogen atom in host molecules with a fluorine atom.

Formerly degenerate seventh zinc finger domain from transcription factor ZNF711 rehabilitated by experimental NMR structure.

Domain Z7 of nuclear transcription factor ZNF711 has the consensus last metal-ligand H23 found in odd-numbered zinc fingers of this protein replaced by a phenylalanine. Ever since the discovery of ZNF711, it has been thought that Z7 is probably non-functional because of the H23F substitution. The presence of H26 three positions downstream prompted us to examine if this histidine could substitute as the last metal-ligand. The Z7 domain adopts a stable tertiary structure upon metal-binding. The NMR structure of Zn2+-bound Z7 shows the classical ββα-fold of CCHH zinc fingers. Mutagenesis and pH titration experiments indicate that H26 is not involved in metal binding and that Z7 has a tridentate metal-binding site comprised of only residues C3, C6, and H19. By contrast, an F23H mutation that introduces a histidine in the consensus position forms a tetradentate ligand. The structure of the WT Z7 is stable causing restricted ring-flipping of phenylalanines 10 and 23. Dynamics are increased with either the H26A or F23H substitutions and aromatic ring rotation is no longer hindered in the two mutants. The mutations have only small effects on the Kd values for Zn2+ and Co2+ and retain the high thermal stability of the WT domain above 80°C. Like two previously reported designed zinc fingers with the last ligand replaced by water, the WT Z7 domain is catalytically active, hydrolyzing 4-nitrophenyl acetate. We discuss the implications of naturally occurring tridentate zinc fingers for cancer mutations and drug targeting of notoriously undruggable transcription factors.

Effect of cationic surfactants on titration behavior of isotactic and atactic poly(methacrylic acid)

By forming strong complexes with oppositely charged polyelectrolytes, cationic surfactants significantly affect their solution properties. We investigated the effect of bound surfactant on the titration behavior of two isomer forms of poly(methacrylic acid), PMA, atactic and isotactic PMA, aPMA and iPMA, respectively, which are known for the cooperative change in chain conformation in water. The bound surfactant micelles increase the initial degree of ionization, α, of carboxyl groups on PMA, shift the conformational transition to higher α and make it narrower, and exclude the complexed chains from the solution. The titration curves were analyzed in the framework of the Henderson-Hasselbalch theory and the Gibbs free energy change of the conformational transition was calculated. The results were discussed in the context of a complex influence of surfactant on the PMA chain conformation in solution. It is proposed that the PMA-surfactant interaction changes from a so-called hydrophobic mode, which is responsible for the solubilization of the unionized and water-insoluble iPMA at low α, to a predominantly electrostatic one at high α, which leads to the precipitation of both aPMA and iPMA from solution. Constant pH simulations using simple coarse-grained models for the PMA polymers and individual surfactants were performed to rationalize the titration behavior of PMAs in the absence and presence of surfactant. By inducing an attractive interaction between PMA monomers, an excellent agreement between the experimental and numerical titration curves was obtained. Such agreement becomes poorer upon the addition of surfactant; however, the main features of the PMA titration curves are preserved, which supports the role of hydrophobic interactions in PMA-surfactant association at low pH values and that of electrostatics at higher pH.

Synthesis and characterization of Cu(II)‑meso-HMPAO complex as a model for the development of potential 64Cu radiopharmaceutical

In this work, Cu(II) complexes with meso‑HMPAO and d,l-HMPAO were synthesized. The structural characterisation of the isolated compounds has been done by single-crystal X-ray diffraction analysis, FTIR, and mass spectroscopy. Redox properties of complexes and binding to deoxyribonucleic acid (DNA) molecule have been analysed in detail by cyclic voltammetry and DFT calculations. The results of cyclic voltammetry fully agree with the data obtained by DFT calculations and indicate that the first electron removal takes place from the metal, while the second electron is removed from the ligand. The formation of the complex leads to the shift in oxidation peaks of the ligand from ‒0.29 V to 0,47 V and from 1.18 V to 1,24 V, indicating that ligand in the complex is much more difficult to oxidize. Electrochemical data confirmed the binding between the complex and DNA molecules through guanine. DFT calculations show that the complex is suitable not only for binding purine and pyrimidine bases through a coordination bond but also for additional hydrogen and CH-π interactions of the bases with the ligand. The fluorescence titration experiments revealed a moderate binding affinity of the [Cu-HMPAO]ClO4 complex to human serum albumin (HSA). Molecular docking revealed that this ligand preferentially binds to drug binding site 3 of HSA. Therefore, the novel compounds could be of great interest for further investigation, considering the potential anticancer activity, and as a model for the development of radiopharmaceutical with 64Cu.

A new three-dimensional luminescent MOF for the detection of Fe3+, CrO42−, and Cr2O72− in aqueous solution

A new luminescent MOF were synthesized by solvothermal method based on 1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)ethene (TPPE), with the molecular structure of [Zn2(TPPE)0.5(ndc)2]n (ndc = 1,4-Naphthalenedicarboxylic acid) (LMOF-1). The single crystal structure indicates that LMOF-1 stacks in a three-dimensional structure. The fluorescence test results indicate that LMOF-1 emits blue light with quantum yield at 37.93 %, due to ligand–ligand charge transfer. PXRD and TG analysis confirmed that LMOF-1 has good stability, and PXRD analysis after different solvent exchanges confirmed that LMOF-1 has good stability in water. The results of ion titration experiments show that Fe3+, CrO42−, and Cr2O72− have significant quenching effects on LMOF-1, and the detection limits are 3.83 × 10−6 M, 2.57 × 10−5 M, and 4.33 × 10−6 M, respectively. Indicating that LMOF-1 can serve as a multifunctional ion detector.

Fluorenone-naphthyl encapsulated dual sensor for recognition of F− and Hg2+: Syngenetic effect with drug sobisis and molecular docking studies

A novel fluorenone-naphthyl pendant sensor (FTU) possessing thiourea functionality has been synthesized via a simple condensation method and utilized for the recognition of F− and Hg2+ ions in the solution of CH3CN. The addition of F− and Hg2+ ions to the FTU solution led to the appearance of red-shifted absorption bands at 340 and 315 nm, respectively. On the other hand, in the fluorescence spectrum, the two-fold decrease in fluorescence intensity of probe FTU was observed with F− ions; while complete quenching of the fluorescence intensity was noticed with Hg2+ ions at 423 nm. The limit of detection values of F− and Hg2+ ions were found to be 1.02 & 29.1 nM, respectively, measured by UV–vis studies and 0.0185 & 0.81 nM, respectively, measured by fluorescence studies, which are less than recommended by WHO. DFT computational assessments and 1H NMR titration experiments pointed to F− induced deprotonation of thiourea NH signals. However, the chelation-enhanced quenching effect (CHEQ) was held responsible for fluorescence quenching with Hg2+ addition. Moreover, the in-situ formed FTU + F− complex was utilized for secondary sensing of drug sobisis. Furthermore, the real-world applicability of sensor FTU has been successfully scrutinized for the recognition of F− ions in the toothpaste samples. In addition, molecular docking studies revealed that FTU exhibited excellent antibacterial potency towards different gram-positive as well as negative strains.