Evaluation of anticancer potential of tetracene-5,12-dione (A01) and pyrimidine-2,4-dione (A02) via caspase 3 and lactate dehydrogenase cytotoxicity investigations.

Cancer stands as a significant global cause of mortality, predominantly arising from the dysregulation of key enzymes and DNA. One strategic avenue in developing new anticancer agents involves targeting specific proteins within the cancer pathway. Amidst ongoing efforts to enhance the efficacy of anticancer drugs, a range of crucial medications currently interact with DNA at the molecular level, exerting profound biological effects. Our study is driven by the objective to comprehensively explore the potential of two compounds: (7S,9S)-7-[(2R,4S,5S,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione (A01) and 5-fluoro-1H-pyrimidine-2,4-dione (A02). These compounds have demonstrated marked efficacy against breast and cervical cancer cell lines, positioning them as promising anticancer candidates. In our investigation, A01 has emerged as a particularly potent candidate, with its potential bolstered by corroborative evidence from lactate dehydrogenase release and caspase-3 activity assays. On the other hand, A02 has exhibited remarkable anticancer potential. To further elucidate their molecular mechanisms and interactions, we employed computational techniques, including molecular docking and molecular dynamics simulations. Notably, our computational analyses suggest that the A01-DNA complex predominantly interacts via the minor groove, imparting significant insights into its mechanism of action. While earlier studies have also highlighted the anticancer activity of A01, our research contributes by providing a deeper understanding of its binding mechanisms through computational investigations. This knowledge holds potential for designing more effective drugs that target cancer-associated proteins. These findings lay a robust groundwork for future inquiries and propose that derivatives of A01 could be synthesized as potent bioactive agents for cancer treatment. By elucidating the distinctive aspects of our study's outcomes, we address the concern of distinguishing our findings from those of prior research.

Synthesis, biological evaluation and in silico investigations of benzotriazole derivatives as potential inhibitors of NIMA related kinase.

In the current study, a novel compound, bis(3-(2H-benzo[d][1,2,3]triazol-2-yl)-2-(prop-2-yn-1-yloxy)-5-(2,4,4-trimethylpentan-2-yl)phenyl)methane (TAJ1), has been synthesized by the reaction of 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol) (1), propargyl bromide (2) and potassium carbonate. Spectroscopic (FTIR, 1H-NMR, 13C-NMR) and single-crystal assays proved the structure of the synthesized sample. XRD analysis confirmed the structure of the synthesized compound, showing that it possesses two aromatic parts linked via a -CH2 carbon with a bond angle of 108.40°. The cell line activity reported a percent growth reduction for different cell types (HeLa cells, MCF-7 cells, and Vero cells) under various treatment conditions (TAJ1, cisplatin, and doxorubicin) after 24 hours and 48 hours. The percent growth reduction represents a decrease in cell growth compared to a control condition. Furthermore, density functional theory (DFT) calculations were utilized to examine the frontier molecular orbitals (FMOs) and overall chemical reactivity descriptors of TAJ1. The molecule's chemical reactivity and stability were assessed by determining the HOMO-LUMO energy gap. TAJ1 displayed a HOMO energy level of -0.224 eV, a LUMO energy level of -0.065 eV, and a HOMO-LUMO gap of 0.159 eV. Additionally, molecular docking analysis was performed to assess the binding affinities of TAJ1 with various proteins. The compound TAJ1 showed potent interactions with NEK2, exhibiting -10.5 kcal mol-1 binding energy. Although TAJ1 has demonstrated interactions with NEK7, NEK9, TP53, NF-KAPPA-B, and caspase-3 proteins, suggesting its potential as a therapeutic agent, it is important to evaluate the conformational stability of the protein-ligand complex. Hence, molecular dynamics simulations were conducted to assess this stability. To analyze the complex, root mean square deviation (RMSD) and root mean square fluctuation analyses were performed. The results of these analyses indicate that the top hits obtained from the virtual screening possess the ability to act as effective NEK2 inhibitors. Therefore, further investigation of the inhibitory potential of these identified compounds using in vitro and in vivo approaches is recommended.

Protective effects of N-acetyl-l-cysteine against penconazole-triggered hepatorenal toxicity in adult rats.

Introduction: Penconazole (PEN) is a widely applied triazole fungicide. This study sought to define the efficacy of N-acetyl-l-cysteine (NAC) in mitigating PEN-triggered hepatorenal toxicity in rats. Material and Methods: Twenty-eight adult male albino Wistar rats were assigned to four groups: a normal control (NC), a PEN group, a NAC group and a PEN+NAC group. Administration of PEN (50 mg/kg body weight (b.w.) every 2 days) and NAC (150 mg/kg b.w., daily) took place via oral gavage for 10 days. Results: Effective amelioration by NAC of PEN-induced liver and kidney dysfunction was indicated by a significant reduction in the circulating liver and kidney markers (aspartate aminotransferase, alanine aminotransferase, urea and creatinine). Attenuation of PEN-induced oxidative stress and lipid peroxidation in liver and kidney tissues was evident in a significant reduction in malondialdehyde and enhanced total antioxidant capacity. Moreover, NAC significantly reduced the histopathological alterations and the expression of tumour necrosis factor α in liver and kidney tissue. Furthermore, NAC maintained the messenger RNA levels of nuclear factor erythroid 2-related factor 2 (Nrf2), haem oxygenase 1, and Kelch-like erythroid cell-derived protein 1 and prevented nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) protein upregulation caused by PEN. Conclusion: N-acetyl-1-cysteine protected against PEN-induced hepatorenal oxidative damage and inflammatory response via activation of Nrf2 and inhibition of NF-κB pathways.

Discovery of druggable potent inhibitors of serine proteases and farnesoid X receptor by ligand-based virtual screening to obstruct SARS-CoV-2.

The coronavirus, a subfamily of the coronavirinae family, is an RNA virus with over 40 variations that can infect humans, non-human mammals and birds. There are seven types of human coronaviruses, including SARS-CoV-2, is responsible for the recent COVID-19 pandemic. The current study is focused on the identification of drug molecules for the treatment of COVID-19 by targeting human proteases like transmembrane serine protease 2 (TMPRSS2), furin, cathepsin B, and a nuclear receptor named farnesoid X receptor (FXR). TMPRSS2 and furin help in cleaving the spike protein of the SARS-CoV-2 virus, while cathepsin B plays a critical role in the entry and pathogenesis. FXR, on the other hand, regulates the expression of ACE2, and its inhibition can reduce SARS-CoV-2 infection. By inhibiting these four protein targets with non-toxic inhibitors, the entry of the infectious agent into host cells and its pathogenesis can be obstructed. We have used the BioSolveIT suite for pharmacophore-based computational drug designing. A total of 1611 ligands from the ligand library were docked with the target proteins to obtain potent inhibitors on the basis of pharmacophore. Following the ADMET analysis and protein ligand interactions, potent and druggable inhibitors of the target proteins were obtained. Additionally, toxic substructures and the less toxic route of administration of the most potent inhibitors in rodents were also determined computationally. Compounds namely N-(diaminomethylene)-2-((3-((1R,3R)-3-(2-(methoxy(methyl)amino)-2-oxoethyl)cyclopentyl)propyl)amino)-2-oxoethan-1-aminium (26), (1R,3R)-3-(((2-ammonioethyl)ammonio)methyl)-1-((4-propyl-1H-imidazol-2-yl)methyl)piperidin-1-ium (29) and (1R,3R)-3-(((2-ammonioethyl)ammonio)methyl)-1-((1-propyl-1H-pyrazol-4-yl)methyl)piperidin-1-ium (30) were found as the potent inhibitors of TMPRSS2, whereas, 1-(1-(1-(1H-tetrazol-1-yl)cyclopropane-1­carbonyl)piperidin-4-yl)azepan-2-one (6), (2R)-4-methyl-1-oxo-1-((7R,11S)-4-oxo-6,7,8,9,10,11-hexahydro-4H-7,11-methanopyrido[1,2-a]azocin-9-yl)pentan-2-aminium (12), 4-((1-(3-(3,5-dimethylisoxazol-4-yl)propanoyl)piperidin-4-yl)methyl)morpholin-4-ium (13), 1-(4,6-dimethylpyrimidin-2-yl)-N-(3-oxocyclohex-1-en-1-yl)piperidine-4-carboxamide (14), 1-(4-(1,5-dimethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-(3,5-dimethylisoxazol-4-yl)propan-1-one (25) and N,N-dimethyl-4-oxo-4-((1S,5R)-8-oxo-5,6-dihydro-1H-1,5-methanopyrido[1,2-a][1,5]diazocin-3(2H,4H,8H)-yl)butanamide (31) inhibited the FXR preferentially. In case of cathepsin B, N-((5-benzoylthiophen-2-yl)methyl)-2-hydrazineyl-2-oxoacetamide (2) and N-([2,2'-bifuran]-5-ylmethyl)-2-hydrazineyl-2-oxoacetamide (7) were identified as the most druggable inhibitors whereas 1-amino-2,7-diethyl-3,8-dioxo-6-(p-tolyl)-2,3,7,8-tetrahydro-2,7-naphthyridine-4­carbonitrile (5) and (R)-6-amino-2-(2,3-dihydroxypropyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (20) were active against furin.

A 'turn-off' fluorescence sensor for selective Hg(II) based on phenothiazine derivative.

Given how crucial it is to preserve a human-safe and sustainable environment, the rapid discovery of possibly lethal heavy metals such as Hg(II) has drawn much attention in recent years. A novel sensor, known as (E)-2-((10-octyl-10H-phenothiazin-3-yl)methylene)hydrazine-1-carbothioamide (PTZHC), was synthesized as a fluorescence 'on-off' sensor for Hg2+ ions. Coordination alters organic molecule electron densities, quenching the fluorescence intensity. PTZHC was described completely with the help of FTIR and 1 H-NMR spectrum studies. The Hg2+ ion was successfully detected using the PTZHC sensor even when there were other metal ions present. The limit of the detection was estimated to be 2.5 × 10-8  M and the Job's plot examination implied that PTZHC was bound to Hg2+ with a simple 1:1 stoichiometry in s CH3 CN/H2 O (9:1, v/v) suspension. To further cast light on the bridged effect on geometric and optoelectronic characteristics, time-dependent density functional theory (TD-DFT) at the B3LYP/6-31G(d) level and DFT were both examined.

Synthesis and characterization of phenothiazine sensor for spectrophotometric and fluorescence detection of cyanide.

A sensitive and selective phenothiazine-based sensor (PTZ) has been successfully synthesized. The sensor PTZ displayed specific identification of CN- 'turn-off' fluorescence responses with a quick reaction and strong reversibility in an acetonitrile:water (90:10, V/V) solution. The sensor PTZ for detecting CN- exhibits the marked advantages of quenching the fluorescence intensity, fast response time (60 s), and low value of the detection limit. The concentration that is authorized for drinking water by the WHO (1.9 µM) is far higher than the detection limit, which was found to be 9.11 × 10-9 . The sensor displays distinct colorimetric and spectrofluorometric detection for CN- anion due to the addition of CN- anion to the electron-deficient vinyl group of PTZ, which reduces intramolecular charge transfer efficiencies. The 1:2 binding mechanism of PTZ with CN- was validated by fluorescence titration, Job's plot, HRMS, 1 H NMR, FTIR analysis, and density functional theory (DFT) investigations, among other methods. Additionally, the PTZ sensor was successfully used to precisely and accurately detect cyanide anions in actual water samples.

The Impact of TPA Auxiliary Donor and the π-Linkers on the Performance of Newly Designed Dye-Sensitized Solar Cells: Computational Investigation.

The efficiency of the newly designed dye-sensitized solar cells (DSSCs) containing triphenylamine, diphenylamine (TPA), phenothiazine, and phenoxazine as donors and triazine, phenyl with D1-D2-π-linker-π-(A)2 architecture has been investigated using density functional theory (DFT) and time-dependent (TD-DFT) methods. These methods were used to investigate the geometrical structures, electronic properties, absorption, photovoltaic properties, and chemical reactivity. Furthermore, the calculated results indicate that different architectures can modify the energy levels of HOMO and LUMO and reduce the energy gap. The absorption undergoes a redshift displacement. This work aims at calculating the structural geometries and the electronic and optical properties of the designed dyes. Furthermore, the dye adsorption characteristics, such as the optoelectronic properties and the adsorption energies in the TiO2 clusters, were calculated with counterpoise correction and discussed.

Characterization of graphene oxide-ziziphus seeds and its application as a hazardous dye removal adsorbent.

The zizphus seeds are considered as a biomaterial residues that has been used for removing of organic industrial waste such as 2-((10-octyl-9,10-dihydroanthracene-2-yl) methylene) malononitrile (PTZS-CN) dye from aqueous solutions utilizing graphene oxide-Ziziphus (GO-Ziziphus). A batch study explored the impacts of various experimental circumstances, including solution pH, initial dye concentration, temperature, and contact time. General order, nonlinear pseudo-first order and pseudo-second order, elvoich model and intraparticiple diffusion were utilized to analyze the kinetic data. The adsorption kinetics of dye onto GO-ziziphus adsorption was best mentioned by nonlinear pseudo-first order. Similarly, the intra-particle diffusion plots revealed one exponential line throughout the adsorption process. The Freundlich, Dubinin-Radushkevich, and Langmuir models were employed to examine isothermal data. It provided the best fit of the dye adsorption isothermal data onto GO-ziziphus Freundlich models. Besides, the calculated free energies showed that the adsorption progression was physical adsorption. Thermodynamic calculations revealed that dye adsorption onto GO-ziziphus was exothermic and spontaneous. The combined results indicated that GO-ziziphus powder might be used to treat dye-rich wastewater effectively.

Characterization of Date Seed Powder Derived Porous Graphene Oxide and Its Application as an Environmental Functional Material to Remove Dye from Aqueous Solutions.

This study aims to prepare graphene oxide (GO) from raw date seeds (RDSs), considered one of the available agricultural wastes in Saudi Arabia. The preparation method is done by the conversion of date seeds to lignin and then to graphite which is used in a modified Hummer's method to obtain GO. The adsorption of insoluble phenothiazine-derived dye (PTZS) over raw date Seeds (RDSs) as a low-cost adsorbent was investigated in this study. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize (RDSs). According to the calculations, Freundlich isotherms and pseudo-second-order accurately predicted the kinetic rate of adsorption. The adsorption ability was 4.889 mg/g, and the removal rate was 93.98% GO-date Seeds mass, 11 mg/L starting dye concentration, at a temperature of 328 K, pH 9, and contact length of 30 min by boosting the PTZS solution's ionic strength. In addition, the computed free energies revealed that the adsorption process was physical. Thermodynamic calculations revealed that dye adsorption onto GO-date seeds was exothermic and spontaneous.

Green Synthesis and Antibacterial Activity of Ag/Fe2O3 Nanocomposite Using Buddleja lindleyana Extract.

In the study reported in this manuscript, silver/iron oxide nanocomposites (Ag/Fe2O3) were phytosynthesized using the extract of Buddleja lindleyana via a green, economical and eco-friendly strategy. The biosynthesized Ag/Fe2O3 nanocomposites were characterized using UV-Vis spectrophotometry, FTIR, XRD, TEM, DLS and SEM-EDX analyses. The particulates showed a triangular and spherical morphology having sizes between 25 and 174 nm. FTIR studies on the nanoparticles showed functional groups corresponding to organic metabolites, which reduce and stabilize the Ag/Fe2O3 nanocomposite. The antimicrobial efficacy of the phytosynthesized Ag/Fe2O3 against bacterial pathogens was assessed. In addition, Ag/Fe2O3 exhibited broad spectrum activities against B. subtilis, S. aureus, E. coli, and P. aeruginosa with inhibition zones of 23.4 ± 0.75, 22.3 ± 0.57, 20.8 ± 1.6, and 19.5 ± 0.5 mm, respectively. The Ag/Fe2O3 composites obtained showed promising antibacterial action against human bacterial pathogens (S. aureus, E. coli, B. subtilis and P. aeruginosa), making them candidates for medical applications.

D-Carvone Attenuates CCl4-Induced Liver Fibrosis in Rats by Inhibiting Oxidative Stress and TGF-ß 1/SMAD3 Signaling Pathway.

D-carvone is a natural monoterpene found in abundance in the essential oil of aromatic medicinal plants with a wide range of pharmacological values. However, the impact of D-carvone on liver fibrosis remains unclear. This study aimed to evaluate the anti-fibrotic potential of D-carvone in a rat model of liver fibrosis and to clarify the possible underlying mechanisms. Liver fibrosis was induced in rats by carbon tetrachloride, CCl4 (2.5 mL/kg, interperitoneally every 72 h for 8 weeks). Oral treatment of rats with D-carvone (50 mg/kg, daily) started on the 3rd week of CCl4 administration. D-carvone significantly enhanced liver functions (ALT, AST), oxidant/antioxidant status (MDA, SOD, GSH, total antioxidant capacity; TAC), as well as histopathological changes. Moreover, D-carvone effectively attenuated the progression of liver fibrosis, evident by the decreased collagen deposition and fibrosis score by Masson trichrome staining (MT) and α-SMA protein expression. Moreover, D-carvone administration resulted in a significant downregulation of the pro-fibrogenic markers TGF-ß1 and SMAD3 and upregulation of MMP9. These findings reveal the anti-fibrotic effect of D-carvone and suggest regulation of the TGF-ß1/SMAD3 pathway, together with the antioxidant activity as a mechanistic cassette, underlines this effect. Therefore, D-carvone could be a viable candidate for inhibiting liver fibrosis and other oxidative stress-related hepatic diseases. Clinical studies to support our hypothesis are warranted.

The ameliorative effect of N-acetylcysteine against penconazole induced neurodegenerative and neuroinflammatory disorders in rats.

Penconazole (PEN) is a widely used systemic fungicide to treat various fungal diseases in plants but it leaves residues in crops and food products causing serious environmental and health problems. N-acetylcysteine (NAC) is a precursor of the antioxidant glutathione in the body and exerts prominent antioxidant and anti-inflammatory effects. The present study aimed to explore the mechanistic way of NAC to ameliorate the PEN neurotoxicity in male rats. Twenty-eight male rats were randomly divided into four groups (n = 7) and given the treated material via oral gavage for 10 days as the following: Group I (distilled water), Group II (50 mg/kg body weight [bwt] PEN), Group III (200 mg/kg bwt NAC), and Group IV (NAC + PEN). After 10 days all rats were subjected to behavioral assessment and then euthanized to collect brain tissues to perform oxidative stress, molecular studies, and pathological examination. Our results revealed that PEN exhibits neurobehavioral toxicity manifested by alteration in the forced swim test, elevated plus maze test, and Y-maze test. There were marked elevations in malondialdehyde levels with reduction in total antioxidant capacity levels, upregulation of messenger RNA levels of bax, caspase 3, and caspase 9 genes with downregulation of bcl2 genes. In addition, brain sections showed marked histopathological alteration in the cerebrum and cerebellum with strong bax and inducible nitric oxide synthetase protein expression. On the contrary, cotreatment of rats with NAC had the ability to improve all the abovementioned neurotoxic parameters. The present study can conclude that NAC has a neuroprotective effect against PEN-induced neurotoxicity via its antioxidant, anti-inflammatory, and antiapoptotic effect. We recommend using NAC as a preventive and therapeutic agent for a wide variety of neurodegenerative and neuroinflammatory disorders.

A New Cr3+ Electrochemical Sensor Based on ATNA/Nafion/Glassy Carbon Electrode.

A new electrochemical sensor of metal cation in an aqueous solution based on homobifunctional tridentate disulfide Schiff base and named 1,1'-(-((disulfanediylbis(2,1-phenylene))bis(azaneylylidene))bis(methaneylylidene))bis(naphthalene-2-ol) (ATNA) was easily obtained quantitatively from the condensation reaction of 2-hydroxy-1-naphthaldehyde and2-aminothiophenol, and then fully characterized by spectroscopic techniques for structure elucidation. The molecular structure of ATNA was also confirmed by a single-crystal X-ray diffraction study to reveal a new conformation in which the molecule was stabilized by the O-H…N type intramolecular hydrogen bonding interactions in both moieties. The ATNA was used as a selective electrochemical sensor for the detection of chromium ion (Cr3+). A thin film of ATNA was coated on to the flat surface of glassy carbon electrode (GCE) followed by 5 % ethanolic Nafion in order to make the modified GCE (ATNA/Nafion/GCE) as an efficient and sensitive electrochemical sensor. It was found to be very effective and selective against Cr3+ cations in the company of other intrusive heavy metal cations such as Al3+, Ce3+, Co2+, Cu2+, Ga3+, Hg2+, Mn2+, Pb2+, and Y3+. The detection limit at 3 S/N was found to be 0.013 nM for Cr3+ ions within the linear dynamic range (LDR) (0.1 nM-10.0 mM) of Cr3+ ions with r2 = 0.9579. Moreover; this work instigates a new methodology for developing the sensitive as well as selective electrochemical toxic cationic sensors in the field of environmental and health care.

Synthesis, photophysical properties, and density functional theory studies of phenothiazine festooned vinylcyclohexenyl-malononitrile.

A novel phenothiazine derivative conjugated with vinylcyclohexenyl-malononitrile (PTZ-CDN) was synthesized through the Knoevenagel reaction of 10-octyl-10H-phenothiazine-3,7-dicarbaldehyde with 2-(3,5,5-trimethylcyclohex-2-en-1-ylidene)-malononitrile and fully characterized. The UV-vis absorption spectra of PTZ-CDN in different solvents showed a λmax band at 497-531 nm with a high molar extinction coefficient attributed to intramolecular charge transfer (ICT) with the characteristics of a π-π* transition. Increasing the solvent polarity resulted in a bathochromic shift of λmax . The PTZ-CDN fluorescence emission spectra were more sensitive to increasing the solvent polarity than the absorption spectra; they displayed a blue shift of λem by 85 nm. To understand the behaviour of the PTZ-CDN derivative, Stokes' shift ( Δ ν ¯ ) with respect to the solvent polarity, Lippert-Mataga and linear solvation-energy relationship (LSER) models were applied in which the LSER showed better regression than the Lippert-Mataga plots (r2 = 0.9627). Finally, the TD-density functional theory (DFT) electronic transition spectra in dioxane and dimethyl formamide (DMF) were calculated. The DFT data showed that λmax resulted from the support of the highest occupied molecular orbital to the lowest unoccupied molecular orbital transition with 74% and 99% in dioxane and DMF, respectively.

Synthesis, modelling, and solvatochromic properties of a phenothiazine derivative.

A new A-π-D-π-A phenothiazine derivative, 2,2'-((10-octyl-10H-phenothiazine-3,7-diyl)bis (ethene-2,1-diyl))bis(1-ethyl-3,3-dimethyl-3H-indol-1-ium)iodide (PTZ-BEI) was prepared and fully characterized using infra-red (IR), 1 H nuclear magnetic resonance (NMR), 13 C NMR, ultraviolet-visible light and mass spectra. Electronic spectra of PTZ-BEI solutions in solvents with different polarities displayed absorption bands (λmax ) related to intramolecular charge transfer. In addition, the emission spectra of PTZ-BEI solutions were strongly solvent dependent for both wavelength and intensity. Stokes' shift ( Δ ν ¯ ) increased with increasing solvent polarity up to 4105 cm-1 in the most polar solvent, dimethylformamide. The linear solvation-energy relationship was utilized to investigate solvent dependency of the Stokes' shifts. Relative quantum yield (φ) of PTZ-BEI was calculated. Finally, density functional theory was employed at the B3LYP level for geometrical optimization and simulation of electron spectra for the PTZ derivative in gaseous and solvated states to explore the solvent effect.

A new phenothiazine-based selective visual and fluorescent sensor for cyanide.

A new donor-π-acceptor derived from phenothiazine, namely 2-(2-((10-hexyl-10H-phenothiazin-3-yl)methylene)-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (PTZON) was synthesized and fully characterized, and its potential as a fluorescent sensor for cyanide anion was investigated. The PTZON showed a visible absorption band at 564 nm corresponds to an intramolecular charge transfer (ICT) and an emission band at 589 nm in CH3CN/H2O. The results of cyanide anion titration revealed ratiometric changes in both absorption and fluorescence spectra as a result of the nucleophilic addition of cyanide anion via Michael addition. The optical studies, FT-IR spectra, NMR, high-resolution mass, and DFT calculations confirmed the sensing mechanism. The selectivity of PTZON as a cyanide anion fluorescent sensor was proved in mixed solvent solutions, and the sensitivity was as low as 0.011 µM, which is far lower than the value allowed by the United States Environmental Protection Agency for drinking water (1.9 µM). Also, the detection limit of PTZON was assessed to be 3.39 µM by the spectrophotometric method. The binding stoichiometry between PTZON and cyanide anion was found to be 1:1 as evidenced by mass spectra. TLC silica-coated plates test strips demonstrated the fluorescent detection of cyanide anion.

Synthesis and photophysical studies on a new fluorescent phenothiazine-based derivative.

A new typical phenothiazine compound functionalized with thienyl-indandione derivative (PTZTID) was synthesized and characterized using spectral analysis (ultraviolet-visible (UV-vis) light, infrared (IR), 1 H nuclear magnetic resonance (NMR) and 13 C NMR tools). The UV-vis absorption spectra of the PTZTID solution in 1,4-dioxane showed two absorption bands attributed to localized aromatic π-π* transitions of conjugated aromatic moieties and intramolecular charge transfer with the characteristics of a π-π* transition. The fluorescence spectra exhibited a maximum emission wavelength at 580 nm. The effect of concentration on photophysical properties took the form of a minor hypsochromic shift, which was attributed to some extent to the occurrence of H-type aggregation of the PTZTID derivative. Binary solvent effects on the spectroscopic behaviour of PTZTID were measured at different H2 O/1,4-dioxane ratios. Similarly, when increasing the water content, a hypsochromic shift was observed that resulted from H-type aggregation. Furthermore, geometry and electronic configurations of PTZTID were studied at density functional theory /B3LYP level and indicated that the compound had a nonplanar (butterfly structure).

Selective "Turn-On" Fluorescent Sensor for Cyanide in Aqueous Environment and Test Strips.

A new very sensitive and selective fluorescent phenothiazine probe for the recognition of cyanide ions in an aqueous environment was prepared. The detection mechanism depends on the nucleophilic addition of cyanide ions to the fluorescent probe to result in fluorescent change go together with color change from purple to yellow. The prepared phenothiazine sensor was employed for invention of test strips able to recognize cyanide in aqueous media. It was found that the phenothiazine probe could selectively detect cyanide ions. When adding cyanide anions, the color of the yellow phenothiazine solution in dichloromethane changed to yellowish green, while a stronger green emission was monitored under UV lamp. Furthermore, the existence of 10 equivalents of other anions, including AcO-, HSO4-, Cl-, Br-, I-, H2PO4-, did not result in apparent variations in the UV-Vis absorption and fluorescent emission spectra. The recognition limit of phenothiazine probe to cyanide aions was 7.2 × 10-8 mol/L in dichloromethane.

Fabrication of Sb3+ sensor based on 1,1'-(-(naphthalene-2,3-diylbis(azanylylidene))bis(methanylylidene))bis(naphthalen-2-ol)/nafion/glassy carbon electrode assembly by electrochemical approach.

A new Schiff base named 1,1'-(-(naphthalene-2,3-diylbis(azanylylidene))bis (methanylylidene))bis(naphthalen-2-ol) (NDNA) derived from 2,3-naphthalenediamine and 2-hydroxy-1-naphthaldehyde was synthesized by condensation reaction and then characterized by spectroscopic techniques for structure elucidation. In addition to spectroscopic techniques, the molecular structure of NDNA was clearly confirmed by single-crystal X-ray diffraction study. A thin film of NDNA was fabricated onto glassy carbon electrode (GCE) using 5.0% ethanolic nafion solution as a conducting binder in order to develop the cationic electrochemical sensor (NDNA/nafion/GCE) for the sensing of heavy-metal cations in aqueous systems by electrochemical technique. This newly designed sensor exhibited higher sensitivity and selectivity towards antimony (Sb3+) in the presence of other interfering heavy metal cations, as well as long-term stability. Fascinating analytical parameters such as limit of detection (LOD = 0.075 nM, SNR of 3), limit of quantification (LOQ = 0.25 nM) and sensitivity (12.658 × 10-4 µA µM-1 cm-2) were calculated from the calibration curve plot, which shows a linear dynamic range (LDR) of Sb3+ ion concentration from 0.1-10.0 mM. This work presents a new approach towards the development of sensitive, efficient as well as selective toxic cationic electrochemical sensors in the environmental and healthcare fields. Hence, this newly designed NDNA/nafion/GCE presents cost-effective and efficient outcomes and can be used as a practical substitute for the efficient detection and removal of Sb3+ ions from water samples.