A novel fluorometric chemical sensor (PY-2TH) based on 2-thiohydantoin (2TH) in conjugation with pyrene (PY) was designed by facile one-pot Knoevenagel condensation reaction and explored for the ...sensitive and selective detection of Hg2+ ion in solution and solid state methods. Different analytical techniques like NMR and LC-MS concomitantly confirmed the structure of PY-2TH. Absorption and emission studies demonstrate positive solvatochromic effects indicating intramolecular charge transfer in polar solvents. PY-2TH exhibits unprecedented selectivity for detecting Hg2+ ions in tetrahydrofuran (THF) through turn-OFF fluorescence with 90% decrease in the emission intensity with a limit of detection (LOD) of ∼4.4 ppb. The mechanistic investigation through NMR and optical studies confirm the formation of a 2:1 complex between PY-2TH and Hg2+. Thin films of PY-2TH exhibits the J-aggregate formation in the solid state leading to a shift in the emission towards the near-infrared region. Further, we have demonstrated the applicability of PY-2TH for detection of Hg2+ ions and fluorescence imaging in live Zebrafish larvae and the toxicological effects are explored. Cytotoxic evaluation on Zebrafish larval cells revealed that PY-2TH is found to be non-toxic. Detailed analysis demonstrate the potential of PY-2TH for ultra-sensitive Hg2+ ion detection and removal in aqueous environments, highlighting its applicability for identification of metal contamination in live organisms and environmental toxicity.
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•Novel fluorescent PY-2TH designed using 2-thiohydantoin and pyrene through one-pot Knoevenagel condensation reaction.•Solvatochromic effects observed in absorption and emission studies concur intramolecular charge transfer in polar solvents.•PY-2TH demonstrates remarkable selectivity for detection of Hg2+ ions, exhibiting turn-OFF behaviour with LOD of 22 nM.•Assess the metal contamination in live organisms and environmental toxicity.
Corrosion is a harmful processes which by definition is a chemical or electrochemical reaction between a substance (usually a metal) and the environment which leads to a change in the properties of ...the substance and has destructive effects. In this study, new composites consisting of Al/WS2/ZnTerp-2TH with 5 and 10 wt.% ZnTerp-2TH were prepared and the results were fully compared. Al/WS2 played the role of matrix and ZnTerp-2TH played the role of reinforcement. In other words, as a novelty to prevent the corrosion of Al/WS2, ZnTerp-2TH is designed and synthesized and showed good results when the corrosion ratio was reduced by the existence of ZnTerp-2TH. Furthermore, the NMR and mass analysis of ZnTerp-2TH were carried out, and the thermal properties, X-ray diffraction, Fourier-transform infrared (FTIR) spectroscopy, morphology, energy-dispersive X-ray spectroscopy (EDX) analysis and corrosion behavior of the composites were also discussed in detail. The crystal size values of composites were calculated by the modified Scherrer method 34, 26 and 27 nm for Al/WS2, Al/WS2/5 wt.% ZnTerp-2TH and Al/WS2/10 wt.% ZnTerp-2TH, respectively. The microstructural examination of the specimens showed that the reinforcing phase (ZnTerp-2TH) has a favorable distribution on the surface of Al/WS2 when it covers the cracks and holes. In addition, the corrosion investigation results showed that the addition of ZnTerp-2TH to Al/WS2 can improve the corrosion resistance when the Ecorr and Icorr values of Al/WS2/10 wt.% ZnTerp-2TH were recorded in tandem −724 mV/decade and 5 uA cm−2.
A novel fluorescent chemosensor (
TPA-2TH
) containing triphenylamine (TPA) appended in conjugation with 2-thiohydantoin (2TH) is developed and confirmed by various analytical techniques like FT-IR ...spectroscopy, NMR spectroscopy, HR-MS and single crystal X-ray diffraction (SC-XRD). The crystal structure analysis revealed a propeller-shaped TPA unit and a co-facial herringbone packing arrangement stabilized by N-H S, N-H O and C-H O in the crystal lattice.
TPA-2TH
exhibited a strong absorption band at ∼431 nm and emitted a yellow-green fluorescence at
λ
max
= 522 nm in THF, attributed to an efficient charge-separated state resulting from ICT between TPA and 2TH. A solvatochromic effect was observed with a red shift in the emission wavelength as the polarity of the solvent increased.
TPA-2TH
showed unprecedented selectivity with
turn-off
fluorescence upon complexation with diamagnetic Hg
2+
ions, attributed to an increase in the spin-orbit coupling and a weakened ICT effect caused by Hg
2+
binding. The addition of Hg
2+
to
TPA-2TH
resulted in the formation of a 2 : 1 complex (
TPA-2TH
-Hg
2+
), confirmed by the coordination of a sulphur atom of
TPA-2TH
with Hg
2+
ions, as evidenced by
1
H NMR spectroscopy and Job's plot analysis. A linear relationship between the fluorescence intensity of
TPA-2TH
and the concentration of Hg
2+
ions is observed with a LOD of 3.3 pM. Furthermore, the toxicological effect of
TPA-2TH
is explored in zebrafish larvae and embryos to provide a sensitive bio-indicator for metal ion contamination and fluorescence imaging. This comprehensive approach combining fluorescence quenching and behavioural toxicity assessment offers a practical method for evaluating metal ion contamination and its potential toxic effects on aquatic organisms with acute behavioural toxicity end points using adult zebrafish.
A novel triphenylamine based push-pull fluorophore (
TPA-2TH
) bearing a 2-thiohydantoin unit for detection of toxic Hg
2+
ion and its live cell imaging in Zebrafish.
Novel amphiphilic Zn(II)phthalocyanines (ZnPcs) peripherally substituted with four and eight dimethylaminopyridinium units (ZnPc1 and ZnPc2) were synthesized by cyclotetramerization of the ...corresponding phthalonitriles. The effect of aggregation and photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation under light irradiation) properties was investigated. The chemosensing ability of ZnPcs toward explosive nitroaromatic compounds was explored in aqueous medium. This study demonstrates that ZnPc1 and ZnPc2 show fluorescence quenching behavior upon interaction with different nitro analytes and show unprecedented selectivity toward 2,4,6-trinitrophenol with a limit of detection (LOD) of 0.7–1.1 ppm with a high quenching rate constant (K sv) of 1.6–2.02 × 105. The near-infrared (NIR) fluorescence in thin films was quenched efficiently because of the photoinduced electron-transfer process through strong intermolecular π–π and electrostatic interactions. The sensing process is highly reversible and free from the interference of other commonly encountered nitro analytes. Further, experiments were performed to demonstrate the use of ZnPcs as efficient heterogeneous photocatalysts in the reduction of nitro explosives. The smart dual performance of multicharged ZnPcs in aqueous media quantifies them as attractive candidates in developing sensor materials at the NIR region and to possibly convert the toxic explosives into useful scaffolds. These results provide an interesting perspective toward elaboration of stable fluorescent systems for the selective sensing behavior of nitro explosives and their facile heterogeneous catalytic behavior in the reduction reactions.
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•Simple functionality and small size are the advantages of the phenothiazine to develop a low cost material.•Being simple secondary amine with an amine content of 7.5 % the molecule ...exhibits a CO2 capture capacity of 17 mg/g.•A linear response is obtained for CO2 concentration varied between 0.04 to 15 %, thus, this material can be used for direct CO2 capture from air.
Globally, CO2 levels are rising and thus, dedicated efforts are driven towards CO2 capture and storage. In this work, we have demonstrated for the first time CO2 adsorption and storage by phenothiazine (Pheno) molecule. The amine functionalities of Pheno are exploited for the chemisorption of CO2. A maximum of 0.4 mmol/g of CO2 is adsorbed which equates to 17.6 mg CO2 captured/g of Pheno molecule. This value may seem less but the small size, simplistic functionalities, and cheap cost make this study relevant for CO2 mitigation. The CO2 stored on the Pheno molecule is chemisorbed to form strong carbamide (amide linkage) and thus, difficult to desorb even at a temperature of 150 °C. This shows that CO2 is stored strongly (via chemical bond formation) and safely thus, could reduce the accidents resulting from accidental leakage/desorption of CO2 which could be fatal. Pheno based sorbent shows linear response over various concentrations ranging from atmospheric concentration of CO2, 400 ppm to 15% concentrations of CO2 at ambient conditions. The adsorption efficacy of Pheno exponentially decreases with an increase in temperature above room temperature. However, the adsorption efficiency increases with an increase in relative humidity as non-condensable water molecules further provide an additional site for CO2 dissolution and bicarbonate formation which increases CO2 uptake.
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•Curcumin loaded surface coated Fe3O4 magnetic nanoparticles grafted with dextran.•The impacts of the surface coating were correlated with the colloidal property.•High affinity of ...carboxyl group with positive iron surface confirms dextran layer.•No significant change in magnetization even after dextran coating.•Cytotoxicity tests shows significant cytotoxic effect on A549 cancer cells.
Surface coating of Magnetic Nanoparticles (MNPs) plays a key role in the prohibition of agglomeration, improved colloidal stability, and biocompatibility. This research aims to develop and evaluate curcumin-conjugated dextran-coated MNPs for the cytotoxic potential of lung cancer cell A549. Fe3O4 NPs were prepared by a simple co-precipitation method followed by surface coating with dextran. FT-IR, micro Raman, and powder XRD results confirm that functionalization does not alter the crystallinity of Fe3O4 and the particle size varied from ∼ 147–216 nm. The surface morphology of the conjugate shows that the drug-polymer embedded homogeneously over the surface. The in vitro release of the drug shows ∼ 77.80 ± 5.4 % and ∼ 5.15 ± 3.3 % from Cur-Dex-Fe3O4 NPs and curcumin suspension over 24 h. The IC50 value of 22.5 μg/mL with significant changes in the chromatin of cells was observed in the MTT assay and Hoechst 33,528 staining. The developed Cur-Dex-Fe3O4 NPs can effective against the A549 lung cancer cell line.
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•Free base porphyrin doped in borate glass films developed through melt quenching technique.•Strong red shifted absorption and emission in the glass matrix.•Non-planarity of the ...porphyrins induces the variation in the excited state lifetimes.•Tunable two-photon absorption and enhancement of optical limiting response in the glass matrix.
Two different types of freebase porphyrins with variation in the central core, namely H2TPP (meso-5,10,15,20- tetrakis phenyl porphyrin) and HSTPP (meso-tetrakis 5,10,15,20-tetra-phenyl-23-H-21-thiaporphyrin) were introduced into the borate glass matrix and developed the thin films by melt quenching technique. Due to core modification and extended non-planarity in the glass matrix, the absorption spectrum of HSTPP shows a strong redshift in the soret and Q bands. Emission spectra of HSTPP show an intense emission at 739 nm (S1 → S0) and ~ 505 nm due to coordination of boron atom at the central core and freezing of N-BO3 vibrations furnishes slow relaxation from higher energy states. Comparison studies are made by treating with BF3O(C2H5)2 to mimic structure in the borate glass matrix due to boron coordination at the central core. The excited state lifetimes are shortened due to BF3 interaction in the solution as well as in the borate glass matrix endowing its potential to develop the optical limiting devices. Nonlinear optical studies reveal reverse saturable absorption (RSA) behaviour in the picosecond (ps) region and show enhanced two photon absorption (TPA) by core modification. Optical power limiting measurements on HSTPP in glass matrix delivers a better limiting threshold value of 15.2 mJ/cm2.
Graphene, in its pristine form and analogs, is revolutionizing the architecture and designing of materials for high-performance optoelectronic devices. The functionalization of graphene is very ...attractive and emerging field of interest for nonlinear optical devices. In this work, we have synthesized Graphene oxide (GO) decorated with TiO2 semiconducting nanoparticles for nonlinear photonic devices. The nonlinear optical (NLO) measurements of GO-TiO2 composite were studied with a popular Z-scan technique for optical power limiting applications. Functionalized graphene oxide with TiO2 nanoparticles exhibits a strong enhancement in optical-response with nanosecond laser pulses. The composite show fingerprints of reverse saturable absorption (RSA) dominated by two-photon absorption (TPA) along with enhanced nonlinear absorption due to transfer of electrons/energy between TiO2 nanoparticles and graphene oxide. The systematic spectroscopic studies with TEM, XRD, FT-IR, micro-Raman, steady-state and time-resolved photoluminescence reveals that successful conjugation of GO and TiO2 nanoparticles and probes the structural and optical properties. The nonlinear optical measurements demonstrate that GO-TiO2 composite exhibits promising optical power limiting features than individual counterparts implicating the potential contingent towards broadband optical limiting applications.
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•Functionalization of GO with TiO2 nanoparticles exhibit large improvement of optical property in the nonlinear regime.•GO-TiO2 composite shows reverse saturable absorption (RSA) due to dominant two photon absorption (TPA).•GO-TiO2 composite exhibits high damage and low limiting thresholds leading to promising optical limiting material.
Corrosion is a harmful processes which by definition is a chemical or electrochemical reaction between a substance (usually a metal) and the environment which leads to a change in the properties of ...the substance and has destructive effects. In this study, new composites consisting of Al/WSsub.2/ZnTerp-2TH with 5 and 10 wt.% ZnTerp-2TH were prepared and the results were fully compared. Al/WSsub.2 played the role of matrix and ZnTerp-2TH played the role of reinforcement. In other words, as a novelty to prevent the corrosion of Al/WSsub.2, ZnTerp-2TH is designed and synthesized and showed good results when the corrosion ratio was reduced by the existence of ZnTerp-2TH. Furthermore, the NMR and mass analysis of ZnTerp-2TH were carried out, and the thermal properties, X-ray diffraction, Fourier-transform infrared (FTIR) spectroscopy, morphology, energy-dispersive X-ray spectroscopy (EDX) analysis and corrosion behavior of the composites were also discussed in detail. The crystal size values of composites were calculated by the modified Scherrer method 34, 26 and 27 nm for Al/WSsub.2, Al/WSsub.2/5 wt.% ZnTerp-2TH and Al/WSsub.2/10 wt.% ZnTerp-2TH, respectively. The microstructural examination of the specimens showed that the reinforcing phase (ZnTerp-2TH) has a favorable distribution on the surface of Al/WSsub.2 when it covers the cracks and holes. In addition, the corrosion investigation results showed that the addition of ZnTerp-2TH to Al/WSsub.2 can improve the corrosion resistance when the Esub.corr and Isub.corr values of Al/WSsub.2/10 wt.% ZnTerp-2TH were recorded in tandem −724 mV/decade and 5 uA cmsup.−2.
The inorganic phosphors doped with different rare earth ions are of more significant to develop new class of lighting devices to fulfill the present technological desires owing to their compact size, ...high colour rendering index with high luminescence efficiency, eco-friendly behaviour. The present research work reports the synthesis, structural, morphological and optical analysis of Sr3Gd(PO4)3: Tb3+ phosphors for lighting applications. These phosphors were synthesized via modified citrate gel-combustion technique with varied concentrations of Tb3+ and they were crystallized into BCC phase. The morphological investigations reveal an agglomeration of particles distributed non-uniformly in the crystal lattice. Upon excited at near UV radiation, the phosphors emit intense green luminescence through 5D4 → 7FJ transitions. The colour perception studies were carried out by evaluating the chromaticity coordinates (x, y). The experimental investigations explore that the studied phosphors are more suitable for lighting applications.
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