Search

We designed the new xanthene dyes by introducing the donor and acceptor group of electrons in the 5' position of the carboxyphenyl ring. These synthesized dye molecules were identified using spectroscopy. And the photophysical studies, such as solvent optimization, were further explored before and after photodegradation of all synthesized dye compounds in both states (solution and solid). The resulting dyed modacrylic fabrics and measured their K/S values, reflectance (%), solid UV absorbance, and photoluminescence. All compounds are plotted on a chromaticity map in the pink region. During photodegradation, the stability of the molecule depends on the effect of the functional groups (donor to acceptor). In this case, ln[C/C0] (%) became the decreasing sequence from an electron donor to acceptor, as the electrons followed from the donation function group to the carboxylic function group. Therefore, the electron-accepting group dyes decompose rapidly during ultraviolet radiation.

This work describes a new ternary nanocomposite of TiO2 nanospheres decorated on the surface of graphitic carbon nitride (C3N4)-porphyrin (TCP) via the sonochemical method (WUC-D22H, Daihan Scientific, Korea). The ultrasonic frequency and power were 20 kHz and 100 W, respectively. The structure and morphology of the synthesized nanocomposites were systematically characterized by FT-IR, XRD, SEM, UV-DRS, and mapping analysis. Compared to its single and binary components, the ternary nanocomposite TiO2@C3N4-TCP clearly shows higher photocatalytic action against Rhodamine B (Rh–B) dye contaminants in the visible region. Ternary nanocomposite TiO2@C3N4-TCP catalysts have good stability and reusability for four successive photocatalytic discoloration tests. These materials consist of synergistic nanocomposites with enhanced visible light adsorption, effective charge separation, and low rate recombination dynamics. In addition, it has been clarified that hydroxyl and superoxide radical active species play some auxiliary roles, whereas the holes play the main role in the photodiscoloration of Rh–B. Moreover, as expected this work presents a novel approach towards advanced ternary nanocomposites in visible light adsorption aimed at the photodecomposition of pollutants via the photocatalytic process.

Carbon nitride based photocatalysts are widely used to decontaminate aqueous solutions by eliminating toxic and non-biodegradable compounds. It is desirable to develop a photocatalyst with high charge separation and migration efficiency. In this study, synergistic ternary porous carbon nitride–polypyrrole–montmorillonite (CN–PPy–MMt) was successfully synthesized via an in situ oxidative polymerization method. The photocatalytic performance towards mineralization of metronidazole (MZ) under visible light was studied, where the CN–PPy–MMt (10%) nanocomposite exhibited the best performance compared to CN–PPy–MMt (5%, 15%, 20%), CN–PPy, pure CN and other nanocomposites reported. This superior photocatalytic mineralization performance was attributed to synergistic inter-constituent interactions within the CN–PPy–MMt nanocomposite, which effectively enhanced the light absorption capacity and charge transfer, and reduced the recombination of electron–hole pairs. The results were confirmed by UV-DRS, photocurrent, impedance, and photoluminescence measurements. The effect of interfering anions was examined and the results indicated that the MZ mineralization efficiency was significantly inhibited by the addition of HCO3− and PO43−. The reusability and stability of the photocatalyst were excellent even after five repeated photocatalytic reactions. Analysis of the radical scavenger properties indicated that superoxide radicals (˙O2−) and holes (h+) played a major role in the mineralization of MZ. The intermediate products were confirmed using liquid chromatography-mass spectrometry, which provided an insight into the MZ mineralization mechanism. This work suggested that the design of a ternary nanocomposite based on CN with conducting polymers could be an effective strategy to improve the photocatalytic mineralization of antibiotics and energy related applications.

We designed the TPA-based linear pyrazine derivatives of PP-1 and PP-2, synthesized using the conventional Suzuki cross-linking reaction. It was followed by photophysical studies such as aprotic solvent (Haxene to DMF). A red-shift was observed from the non-polar aprotic solvent to the polar aprotic solvent, and the emission intensity was gradually decreased. In addition, the Aggregation-induced emission (AIE) effect has been studied against the DMF/water addition of linear pyrazine compounds. It showed a classic aggregation-caused quenching effect (ACQ) and red-shifted at an increase of (f

We constructed a novel-binding site for metal ion detection using a fused tetrazole ring conjugated with aminopyrene (R). The designed structure of the molecule was successfully synthesized and determined the probe's selectivity by testing various metal ions and found that the probe effectively detects Al

A new chromone moiety fused with phenyl hydrazine carboxamide as a binding site for metal ion was designed and synthesized as a colorimetric/fluorimetric probe for selective sensing of Al3+ ion. The absorption and fluorescence spectral results showed selective and sensitive recognition of Al3+ with no significant interference from other competitive metal ions. The addition of Al3+ to R brought a prompt color change from colorless to yellow and the turn-on fluorescence response with Al3+ among different cations was studied. The visible color change and turn-on fluorescence Al3+ ion with R was attributed to the intra molecular charge transfer transition. The plausible binding nature of the receptor with Al3+ has also been anticipated by the results of 1H NMR and mass spectral analysis. For the practical effectiveness, test strip prepared using probe R was successfully applied to monitor the presence of Al3+ ion in aqueous medium.

Dye degrading property to exhibit self-cleaning effect in Poly Ethylene Terephthalate (PET) through photocatalytic effect by Metallo porphyrin and TiO₂ has been studied in detail. PET has been modified by step wise deposition of anatase TiO₂ and Metallo porphyrin (CuTCNPP, NiTCNPP, ZnTCNPP), self-cleaning property of the modified PET has been studied by photo degradation of rhodamine B (RB) by irradiation under visible light and the degrading ability and the efficiency has been monitored using UV-Vis spectral technique by measuring the change in concentration of RB in the PET at different time intervals. Stability of Metallo porphyrin in PET also measured by UV-Vis spectral method. Indicating the porphyrin attached in PET are highly stable after washing the samples with detergent, water even after irradiating under visible light for more than 5 h. The degradation effectiveness found to be in the order of PET/TiO₂/ZnTCNPP > PET/TiO₂/CuTCNPP > PET/TiO₂/NiTCNPP > TiO₂ > PET. The modification made in the PET samples were characterized and confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible spectroscopy (UV-Vis), Field emission scanning electron microscope (FESEM) analysis and the prepared Metallo porphyrin has been confirmed through mass analysis.

In this paper, we prepared a new class of chemically linked UV absorber XU2XU3, and their photophysical, chemical properties and substrate durability were investigated. Spectroscopic behavior at various solvent and pH levels for this dye solution has been evaluated. Successfully designed an open ring form of xanthene moiety, linked a UV absorber to it, and made XU2XU3 that have shown good absorbance and emission band maxima at all solvents and pH mediums. Further, the found UV-Vis absorbance band maxima (λ

Hollow porous graphitic carbon nitride (porous CN) was synthesized via a simple tactic method, and the resulting porous CN showed an effectively modified surface area, crystal structure and enhanced photocatalytic performance. Optical and electrochemical characterization results demonstrated an increase in the charge transfer rate and a decrease in recombination tendency.

A visible light sensitized hydrophilic self-cleaning poly ethylene terephthalate (PET) fabric exhibiting photocatalytic dye degrading properties has been prepared by step wise deposition of anatase TiO2, porphyrin with different anchor groups (TCPP, TCNPP, TPyP), the modified PET fabric showed excellent photo degradation of rhodamine dye. Moreover, the dye degradation ability in visible light irradiation for the modified fabric was also monitored at different time intervals by the UV–Vis spectral technique. The degradation efficiency was found to be in the order of PET/TiO2/TCPP > PET/TiO2/TCNPP > PET/TiO2/TPyP > TiO2 > PET. The surface modified PET was characterized by XPS, UV–Vis, and FESEM. Synthesized porphyrin and TiO2 were confirmed by 1H-NMR and XRD analysis, respectively.

A visible-light sensitized, superhydrophobic, self-cleaning Polyethylene terephthalate (PET) fabric exhibiting photocatalytic dye degrading properties has been prepared by depositing anatase TiO2, porphyrin (TPPS, CuTPPS), and trimethoxy(octadecyl)silane (Si) onto the PET samples. The modified PET fabric showed superhydrophobicity, exhibiting a water contact angle (WCA) of 147°, and the ability to photodegrade rhodamine dye (RB), and the dye degradation ability of the modified fabric under visible light was monitored at different time intervals by UV–Vis spectroscopy. The degradation efficiency was found to be in the order PET/TiO2/TPPS > PET/TiO2/TPPS/Si > PET/TiO2/CuTPPS > PET/TiO2/CuTPPS/Si > PET/TiO2 > PET. The photodegradation ability and superhydrophobicity of the modified PET samples in relation to coffee and ketchup stains were examined qualitatively. Due to its superhydrophobicity, water soluble impurities/coffee drops roll off the surface of the modified PET fabrics, resulting in stain-free fabric. The fabrics were characterized by UV–Vis, FESEM, XRD and XPS. The structures of the synthesized porphyrin and TiO2 were confirmed by 1H NMR spectroscopy and XRD analysis, respectively.

Changes/variations during manufacturing and storage of free radical-polymerized hydroxyl-terminated polybutadiene resin/prepolymer (widely used binder for the composite solid propellants) are not reflected in terms of appreciable change in the hydroxyl value. As a result, cured properties of the propellant mixed using the given formulation finalized by keeping R ratio (NCO/OH ratio) within 0.7–0.9 did not yield predicted mechanical properties. Investigations carried out subsequently, by the authors, identified the root cause to be variations in molecular weight and its distribution, which were not indicated in terms of change in hydroxyl value. Authors confirmed their findings by 1H1NMR studies whereby the variation in molecular weight distribution could be explained in terms of variation in spin–spin relaxation time ( T 2) values.

An easy to make xanthene based optical probe synthesized, precise recognition towards mercury ion been achieved by the probe RP and can detect Hg

Metal oxide-graphitic carbon nitride nanocomposites have attracted great research interest from both scientific and technological viewpoints in the fields of chemistry and materials science. In this chapter, we provide brief introductions, methods of preparation of metal oxide-based g-C3N4, and complete characterizations. In particular, we mainly focus on the synthesis of metal oxide nanoparticles to form composites with g-C3N4 via the hydrothermal method, solvothermal reaction, ultrasonication method, reflux method, sol–gel method, simple precipitation method, in situ method, etc., including recent progress and advances. Due to the extent of this chapter, metal oxide-based g-C3N4 is exclusively focused on the ultrasensitive and selective detection of toxic chemical contaminants, including heavy metals, inorganic anions, phenolic compounds, pesticides, and chemical warfare reagents. Finally, concluding remarks and future challenges and opportunities of metal oxide-based g-C3N4 are presented. This chapter is expected to be comprehensive and useful to the chemistry and materials science community interested in electrochemical toxic pollutant sensors functioning in a real-world environment.

An easy to make xanthene based optical probe synthesized, precise recognition towards mercury ion been achieved by the probe RP and can detect Hg2+ effectively in both for solid and liquid state with a vivid color change. The other tested ion showed no interference, visual and instrumental methods confirms the probe selectivity. Stoichiometry (1:1) confirmed by job’s plot, plausible binding of Hg2+ ion with the probe confirmed by mass and NMR studies. Test strip prepared for the prompt onsite detection in aqueous medium with outstanding color variation in daylight.

9-arylated acridine-based derivatives (AUPAO & AUEA) with high visibility, fluorescence, and excellent lightfastness were synthesized in good yield. The molecules were characterized by 1H NMR, 13C NMR, HRMS and further investigated for photophysical properties. Initially, absorption and emission studies were carried out in wide-ranging polarity solvents to choose a solvent of interest for further investigations. Concentration-dependent studies were carried out in ethanol to determine an optimized concentration to study lightfastness studies. These molecules showed excellent lightfastness properties in solution form when compared to commercially available acridine orange. pH-dependent studies were also carried out to observe the behavior of cationic dyes in a wide range of pH to optimize pH for dyeing. The presence of extended conjugation at the 9th position and additional four methoxy groups resulted in highly fluorescent dyes with excellent quantum yield. The steric interactions, higher twist, and unrestricted rotation of the conjugation pathway between the aromatic ring at the 9th position and the acridine core decreased the transition probability and energy transfer that helped improve the lightfastness. The introduction of a hydroxyl group in AUEA increased the solubility and helped in controlled dispersion while dyeing. Further, they were dyed on modacrylic fabric as high visibility fluorophores, and later the color coordinates, color strengths were measured.

A new chemosensor based on a fluorene-rhodamine conjugate was designed and synthesized for the selective recognition of Hg2+ ion in 80% aq. DMF. The receptor is highly selective and sensitive towards mercury ions over other metal ions in both normal and UV light. A binding constant on the order of 105 was calculated using the fluorescence technique, indicating that the receptor strongly bound the mercury ion. The type of binding and the sensing mechanism were confirmed by 1H, 13C NMR and FT-IR spectral studies. The mechanism by which the receptor senses mercury ions is through rhodamine ring opening process. The prepared R/polyurethane electro spun nanofiber could selectively sense Hg2+ ions in the form of a strip. Finally, the synthesized receptor could be used as a digital printing material and showed a good response to sensing mercury in 100% water.

Three new benzoquinone–imidazole ensembles possessing varying number (0, 1 and 2) of electron-withdrawing bromo substituents on the quinone ring have been designed, synthesized, characterized and employed as receptors in cyanide sensing. These receptors colorimetrically sense cyanide ion selectively and sensitively in aq. 4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid (HEPES) buffer–acetonitrile (ACN) (8:2 v/v) medium with striking colour change that can easily be seen visually. Fluorescence spectral studies revealed that the receptors form strong complex at 1:1 stoichiometry with cyanide ion. The binding constants for the complexes were found to be in the order of 105–107 M−1 and increase with increasing number of bromo substituents on the quinone ring. The detection limit of cyanide by these receptors lay in the range of 10−8 M. The effects of the number of bromo substituents on the absorption maximum, reduction potential and H-bond donor (HBD) property of imidazole N–H are discussed. The results of spectral studies corroborate well with those of electrochemical and theoretical studies. An easy-to-use test strip was prepared to test cyanide in aqueous solution of sodium cyanide prepared using deep-well water.

Herein, using intramolecular charge transfer (ICT) transition as a signaling mechanism, a quinoline–benzothiazolium hybrid was designed, synthesized, and developed as a dual channel (colorimetric/turn-on fluorometric) sensor for cyanide in aq. HEPES buffer/DMF (70 : 30 v/v; pH 7.2). This receptor can detect cyanide with very high selectivity and instantaneous response. The mechanism of sensing involves nucleophilic addition of CN− to the C atom of the CN bond of benzothiazolium moiety. This irreversible addition blocks the π-conjugation and ICT transition between quinoline and benzothiazolium moieties and consequently alters the colour and spectral properties. The results of electronic, fluorescence, and 1H & 13C NMR spectral studies corroborated well with those of the DFT calculations.

A new colorimetric and fluorometric chemosensor was developed and synthesized that showed both color and fluorescence changes upon the addition of cyanide ion in 80% aq. DMSO solution and in the solid phase. The chemosensor showed a selective and sensitive response to cyanide ion over other common anions such as F − , Cl − , Br − , I − , H 2 PO 4 − , NO 3 − and AcO − . The binding stoichiometry between the receptor and cyanide ions was found to be 1:2 ratio, and the detection of cyanide occurred through deprotonation coupled with intermolecular proton transfer, which was confirmed by a 1 H NMR titration experiment. The detection limit was calculated to be 7.49 nM, which is much lower than the permissible limit set by WHO (1.9 μM).

An acrylamide-xanthene hybrid polymeric probe was synthesized for the selective and sensitive detection of mercury ions (Hg2+) in 100% water. The non-polymeric form of probe displayed extraordinary selectivity above other additional metal cations via both a visual color change and fluorescence change with exceptional reversibility and responds rapidly to changes in the environment. The 1H NMR titration study revealed the binding of an Hg2+ ion on the imine hydrogen of the probe by the opening of the spiro-lactam ring, which instigates an instant color change. Reversible behavior of the polymeric probe using an aqueous solution of EDTA was confirmed by both absorption and fluorescence studies. The prepared polymeric probe detects Hg2+ in 100% water and is a promising material for the mercury recognition in real-time.

The azo dye-based visual responsive optical probe 5-(diheptylamino)-2-((3,5-dinitrothiophen-2-yl)diazenyl)phenol (DP), for the purpose of detection toward the mimic molecule of date rape drug was designed, synthesized and characterized. The recognizing abilities toward the mimic molecule (sodium butyrate) of date rape drug (gamma-hydroxybutyric acid) were examined in water. The prepared molecule was visually, analytically, and theoretically confirmed with the sensing ability of the probe. Developing an easy-to-use sensor kit will work spontaneously with a detectable colorimetric response in daylight. Obtained color change from light turquoise color to bluish-purple toward sodium butyrate containing alcoholic beverages was successfully recognized and confirmed. Even though the color change from light turquoise to bluish-purple obtained, which is not easily recognized clearly with the eye under normal light, UV–Visible spectra indicate the changes, thus the probe can be utilized productively to protect the victim from sexual assault.

Dibromobenzoquinone-indole ensembles containing different substituents (OMe, Me, H, Br, and NO 2 ) have been designed, synthesized and characterized using spectral techniques. These chemodosimeters selectively sense cyanide ion colorimetrically with turn-on fluorescence in aqueous HEPES buffer. Absorption and emission spectral studies suggest that the interaction between the receptors and cyanide is strong (binding constant in the order of 10 4 M −1 ) with 1:1 stoichiometry. The detection limit for these receptors to sense cyanide is found to be in the nano molar range which is far below the permissible limit recommended by WHO for cyanide ion in drinking water. 1 H and 13 C NMR titration results indicate that the mechanism of sensing of cyanide by these receptors is through nucleophilic addition of cyanide to the C C bond of the indole ring. The electro-reduction potentials for the quinone moiety before and after the addition of cyanide substantiate the proposed mechanism. Mulliken charges computed, using DFT method, suggest that these receptors possess an electropositive C-atom for the addition reaction to occur, while such charge polarization is not there in similar compounds containing benzoquinone or naphthoquinone. The effect of substituents on the λ ICT , binding constant and δ NH of indole has been explained using Hammett's substituents constants ( σ p ).

Fused silica ceramics was prepared by using conventional organic binder, mathacrylamide-N,N′-methylenebisacrylamide (MAM-MBAM) system by gelcasting process. Mechanical properties of green bodies were studied as a function of solid loading varying from 60 to 72 vol%. After evaluating the green body mechanical properties, the samples were densified at different sintering temperature from 1200 to 1450°C with definite intervals of 50°C and subjected to flexural strength analysis. Variation in flexural strength with sintering temperature was observed and correlated with the quantity of devitrification of fused silica during sintering. Quantification of devitrified cristobalite was carried out by using 20 wt% rutile (TiO2) as an internal standard by X-ray diffraction. It was found that, as the cristobalite content increased, flexural strength decreased. Reliability studies were carried out for the samples having maximum flexural strength with and without crystalline content. Reliability studies have shown that for this organic binder system the sample sintered at 1300°C is crystalline free and most reliable product. The mechanical properties and reliability of this product processed with organic binder are compared with inorganic binder system. Results indicate that the sample fabricated using inorganic binder system is exhibiting high Weibull modulus and thus better reliability.

Two new quinone-imidazole ensembles are prepared, characterized and their fluoride ion sensing properties are investigated in aq. HEPES buffer-DMSO (70–30 v/v) medium (pH = 7.26). Introduction of phenolic hydroxyl group, as an additional H-bond donor moiety, is found to dramatically increase the selectivity of the receptors towards fluoride ion and also accommodates 70% of water in the sensing medium. The hydroxyl group is also found to reduce the acidity of the imidazole N H proton significantly through its strong electron releasing resonance effect (Swain Lupton Constant R = −0.70). The colour of the solutions of these receptors instantaneously changes from yellow to red upon addition of fluoride ion, while it remains unaffected upon addition of other common anions. This observation is well supported by UV–vis, fluorescence titration and quantum yield determination studies. 1H NMR titration indicates that the mechanism of sensing involves formation of H-bonding between fluoride ion and imidazole N H and phenolic O H moieties simultaneously with fairly high binding constants (105 M−1). The results of electrochemical and theoretical studies substantiate the proposed mechanism.

In this work, uniform α-MnO

In this work, the CeO

The self-cleaning effects of polyethylene terephthalate fabric (PET) through the photocatalytic effects of TiO2 (T), porphyrin (P) and silane (S) have been explored ultrasonically using bath type (WUC-D22H, Daihan Scientific, Korea). The ultrasonic power and frequency were 100 W and 30 kHz, respectively. The surface modification in fabric was achieved by the ultrasonic deposition of anatase TiO2 (T), porphyrin (P), and further modification by silane (S) was used to achieve dual-function (photocatalytic and superhydrophobic) self-cleaning behavior. The dye-degrading abilities of the modified fabric surface confirmed by the photo discoloration of various organic pollutants by visible light treatment. From the tested various dye, methylene blue (MB) decomposition was monitored using UV–Vis spectroscopy by measuring the changes in concentrations in the fabric at altered time breaks. The attachment of silane and its stability after washing the surface of fabric confirmed by measuring the water contact angle (WCA). The self-cleaning efficacies were in the order PET@TP > PET@TPS. The modifications are done in fabric surface characterized and confirmed by XRD, XPS, UV–Vis, and FESEM analyses. Fabric's self-cleaning effect examined with common daily life pollutants. Easy to make single-component ink prepared using silane (S) and used as digital printing ink and printed on fabric, exclusively attained hydrophobic surface in the printed area.

This paper describes a new TiO2@TPPS (titanium dioxide @ tetraphenyl-porphyrin sulfonic acid) nanocomposite synthesized via ultrasonic assisted method using a bath-type ultrasonicator at 20 kHz (ultrasonic frequency) and 100 W (ultrasonic power). XRD (X-ray diffraction), FT-IR (Fourier-transform infrared spectroscopy), XPS (X-ray photoelectron spectroscopy), SEM (Scanning electron microscope), EDX (Energy-dispersive X-ray spectroscopy), and UV-DRS (Ultraviolet-visible spectroscopy) were used to systematically characterize the nanocomposite. Compared to TiO2, the TiO2@TPPS nanocomposite obviously exhibits higher photocatalytic activity towards EY (eosin yellow) dye degradation. The optimized weight ratio of 0.1 g of TiO2 nanosphere and 0.01 g of TPPS resulted in efficient discoloration of EY. The EY discoloration was 99 % within 50 min under visible light in the presence of the TiO2@TPPS nanocomposite. Additionally, the nanocomposite catalysts are highly stable and reusable for five consecutive experiments. This performance can be attributed to the synergistic effect of TiO2 and TPPS, which enhanced the charge separation and reduced the rate of recombination. The photodegradation mechanism was also investigated and discussed. It is expected that our work can offer a new way to develop binary nanocomposites with visible-region adsorption for photocatalytic discoloration of organic pollutants and energy applications.

A diquinone–imidazole ensemble (R) is rationally designed, synthesized and employed as a selective and sensitive colorimetric sensor for cyanide ions in DMSO : H2O (1 : 4 v/v). 1H NMR titration indicates that the mechanism of sensing involves the formation of a H-bond between CN− and imidazole N–H. As rationalized, the R–CN− complex exhibited intense NIR-absorption (913 nm; log e 4.3) with a 428 nm red-shift from the absorbance maximum of free R. DFT calculations indicate that the R–CN− complex is perfectly planar with a HOMO–LUMO energy gap of 0.9826 eV which is optimal for NIR-absorption.

A series of four ferrocene based imidazoles (R1–R4), in which the imidazole is attached to different electron acceptor moieties were designed, synthesized and characterized. The anion binding studies were carried out using various techniques including electrochemistry, fluorescence and 1H NMR spectroscopy. Fluorescence studies indicated the formation of strong complexes (Binding constant KA in the order of 106 M−1) between the receptors and cyanide ion selectively. 1H NMR titrations demonstrated that R1–R4 bind cyanide ion through imidazole N–H…CN− hydrogen bond formation. Electrochemical studies using cyclic voltammetric technique displayed “two-wave behaviour” with a cathodic shift of the ferrocene/ferrocenium redox couple (ΔE1/2) up to 269 mV with cyanide ion with a high selectivity. The practical applicability of the receptor has also been investigated.

Three simple ferrocene based chemodosimeters for cyanide ion in aqueous solution have been prepared by one step condensation of commercially available starting materials and characterized spectroscopically. The receptors were designed in such a way that the intra molecular charge transfer (ICT) transition existing between the donor (ferrocene) and acceptor (cyano olefine) moieties imparts an intense pink color to the receptors (log ɛ = 2.92–3.06). The results of UV–vis, fluorescence and 1 H and 13 C NMR spectral studies indicated that the sensing mechanism involves Michael addition of CN − to the electropositively polarized C-atom of the C C bond. Such an addition reaction leads to “turn-off” of ICT transition and thus leading to a striking color change from pink to colorless. The observed variation in the electrochemical reduction potential (Epc) for the reduction of ferrocene moiety and the formation constants of the 1:1 receptor–CN − ion complexes could be explained using the Taft's polar substituent constants ( σ * ) of the substituents attached to the acceptor moiety. Moreover, the test strips fabricated using these receptors could instantaneously sense cyanide ion present in aqueous NaCN solution.

The indolium based sensor (R) system was designed, synthesized, characterized and its cyanide recognizing abilities are examined in 100 % water. The sensor attach with cyanide ion through nucleophilic addition to C atom of the indolium C N group. Also the sensor displayed colorimetric and fluorimetric behavior and it can be simply observed by naked eye. The addition of other chosen anions does not affect the sensor response towards cyanide ion. Test strip constructed on R was act as a convenient test kit to distinguish cyanide ion. Besides, the recognizing ability of sensor has been effectively applied in real water samples and this was validated with HPLC technique. Thus the receptor can be used as an effective sensor to sense cyanide ion water.

In this work, the CeO2@polypyrrole (CeO2@PPy) core-shell nanosphere has been synthesized via an ultra-sonication method using bath type (WUC-D22H, Daihan Scientific, Korea) and they are utilized for the photo-reduction of hazardous Cr6+ to benign Cr3+. The ultrasonic frequency and power were 20 kHz and 100 W, respectively. The PPy shielded CeO2 in aqueous solution could prevent the dissolution of CeO2 and to improve the photocatalytic ability of CeO2. X-ray diffraction was used to confirm the crystalline structure of as prepared CeO2@PPy core-shell and FT-IR was used to identify the functional groups. The uniform sized core of PPy and shell of CeO2 were observed by transition electron microscopy. The ultrasonic assisted synthesized CeO2@PPy core-shell exhibits a narrow bandgap (UV-DRS) and good reduction efficiency with higher reusability and stability compared to pure CeO2, PPy and mechanical mixing of CeO2@PPy. Moreover, the synergistic effect of CeO2 and PPy core-shell structure facilitate a higher electron transfer rate and prolong lifetime of photogenerated electron-hole pairs which can achieve good reduction rate of 98.6% within 30 min. In particular, the pH, catalyst, and Cr6+ concentration effects were optimized in photocatalytic reduction reactions. Meanwhile, this photocatalysis with fast and effective electron transfer mechanism for the Cr6+ reduction was elucidated. This method opens a new window for simple fabrication of conducting polymers-based metal oxide nanocomposite towards wastewater remediation and beyond.

A rhodamine-deoxylactum-based sensor (RDS) as a colorimetric and fluorimetric sensor for the immediate detection of chemical warfare agent mimic diethyl chlorophosphate (DCP) was designed, synthesized and characterized by NMR and mass spectral studies. The DCP-sensing mechanism was triggered by phosphorylation and ring opening of the deoxylactum followed by intramolecular cyclization. The DCP-sensing mechanism was further confirmed by mass spectral analyses. The presence of other metal ions and acids had no influence in the detection of DCP. Furthermore, the prepared test kit was efficient for the detection of nerve gas agent DCP in the gaseous phase that too in both normal light and UV lamp, and the result can be observed with the naked eye.

In the present study, two fluoran molecules (TH1 and TH2) have been synthesized, and their reversible thermochromic properties have been investigated. This work demonstrates the thermochromic reversibility of the fluoran. Furthermore, the three-component mixtures that comprising fluorans (TH1/TH2), bisphenol-A (color developer), and methyl stearate a low melting solvent were used to examine the thermochromic behavior with sturdy heating and cooling rates and the thermochromic properties of the fluorans were detailed using UV-Vis, reflectance and FT-IR spectroscopic techniques. Finally, test strip similar to pH paper and acrylic fiber a versatile material used as thermal indicators also been successfully made from these two fluoran derivatives.