Search

The pyrazole derivatives and its metal complexes are considered to be pharmacologically significant with a variety of pharmacological applications. The present investigation highlights the synthesis of pyrazole based novel ligand, 4-[(E)-(3-hydroxypyridin-2-yl)diazenyl]-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (PDP) and its Co(II), Ni(II), Cu(II) complexes. The structure of the synthesized compounds has been evaluated using various physicochemical and spectroscopic techniques. Cyclic Voltammetry (CV) results are used to confirm the electrocatalytic ability of the modified electrode, [Co(PDP)2]Cl2.2H2O/GCE for the detection of Folic acid (FA) at different concentrations. The CV results displayed good electro-catalytic activity with 10-120 µML-1 with limits of detection (LOD) of 0.0666 µML-1. This electrode has a sensitivity of 2.8784 µAµM-1cm-2 for FA. The bio-efficacy of the synthesized ligand and its complexes have been evaluated against the bacteria (S.aures and E.coli) and fungal (A.flavus and P.anomala) strains using standard method. Antidiabetic study on two different enzymes, a-amylase and a-Glucosidase indicating excellent inhibition by the metal complexes having the maximum IC50 Value of 105.34 for a-amylase and 107.15 mg/mL for a-Glucosidase. [ABSTRACT FROM AUTHOR]

This study presents the development of ultra‐thin azo‐dye polarizers, notable for their minimal thickness (100‐200 nm) and superior optical performance, with polarization efficiency exceeding 99.9%, extinction ratios above 4000, transmittance over 45.3%, and dichoric ratio over 100. Utilizing cost‐effective solution‐processing methods, we fabricate these high‐performance polarizers and determine optimal experimental conditions for peak efficacy. Our research includes comprehensive Scanning Electron Microscopy analyses to understand the microstructural properties of these azo‐dye thin film polarizers, contributing significantly to the field of advanced display technologies. [ABSTRACT FROM AUTHOR]

Vertically Aligned LCD is one of the most widely used optical modes in LCD TV and mobile devices. It is also a very important category of passive LC displays used in Automobiles. It has the advantages of perfect dark state and very high contrast ratio for normal viewing. However, single domain VA LCD has the intrinsic issue of dead zone (contrast vanishing zone) in certain viewing direction in the voltage‐on state, which seriously limits its viewing angle performance. Recently, the State Key Laboratory on Advanced Displays and Optoelectronics Technologies of the Hong Kong University of Science and Technology has developed an easy‐to‐apply multi‐domain VA LCD technology that can be readily implemented in LCD factories without major investment and change in current production process. [ABSTRACT FROM AUTHOR]

Chemical compatibility of water‐soluble azo‐dye photoalignment materials opens up new possibilities of thin‐film optical devices fabrication with advanced characteristics combining several polymerizable liquid crystal layers into multilayer structures of broadband quarter or half wave retarders. However when the azodye photoalignment layer is placed in‐between two layers of polymerizable liquid crystal significant increase of dye absorption is observed. Analysis of this 'Absorption Problem' concludes azodye inter‐layer field is the cause of polarization and cis‐trans equilibrium change. New water‐soluble azo‐dye photoalignment material AmA‐2522 is suggested as perspective problem solution. [ABSTRACT FROM AUTHOR]

Optically driving liquid crystal display (ODLCD) uses polarized light field to control the orientation of the liquid crystal, and the display content can be maintained without external electric field, with extremely low power consumption. However, it has a long rewriting time, which is difficult to achieve industrialization. In order to improve the rewriting performance, the influence of the rotational viscosity of the mixed system of azo-dyes (SD1, MR) and nematic liquid crystal (5CB) on the rewriting speed is investigated. The experimental results show that the electro-optical properties of SD1-5CB and MR-5CB have great changes after irradiation by polarized light, among which the SD1-5CB is the best to improve the performance. With the increase of SD1 concentration, the rotational viscosity of SD1-5CB decreases significantly due to the change of cis-trans isomerization of azo-dye, and the optimal doping concentration is 0.5 wt%. In this case, the rewriting time is shortened from 45 s to 11 s, which has the potential to broaden the application of ODLCD. [ABSTRACT FROM AUTHOR]

Herein we present the production of a two-stage wastewater treatment system for industrial azo-dye using an immobilized nitrogen-doped zinc oxide (ND-ZnO) nanoparticles and a microalgae bioreactor. The treatment system was found capable of reducing up to 95% of methylene blue wastewater in 48 h under a seminatural condition. In the first stage, the immobilized ND-ZnO chamber was found to have photocatalyzed up to 80% using natural sunlight in 4 h. In the second stage, the algae (Chlorella vulgaris) were found to be capable of repeatedly handling the semitreated wastewater and found remained active for at least 7 cycles (hydraulic retention time = 44 h, solid reaction time = 14 days). The algae not only take part in purifying the wastewater but also absorb and metabolize the toxic cleaved by-products therein. The presented system demonstrated a low-cost alternative, both in terms of production and operation, for treatment of recalcitrant azo-dye. Furthermore, unlike other pilot systems using suspended nanoparticles, expensive recovery of nanoparticles is not required and accidental discharge of nanoparticles is avoided. Toxicity assay using fish gill cell line demonstrated that the acute toxicity of the effluent was negligible. To conclude, this novel treatment system opened a new and safe way for effective yet simple treatment of azo-dye wastewater. [ABSTRACT FROM AUTHOR]

Transition and rare-earth metal oxide-supported nanomaterials have ignited an attraction in many fields such as energy, environment and etc. In this work, transition/rare-earth metal oxide-supported carbon-based nanomaterials (TRM) were prepared by hydrothermal method and it was characterized by UV-DRS, FTIR, XRD, AFM, FE-SEM, HR-TEM, and EDAX techniques. Doping levels of transition/rare-earth metal oxides on the carbon-based material impacts the photocatalytic degradation efficiency. The photocatalytic activity (PCA) of the prepared TRM was examined, and the highest degradation percentage was observed compared to other reported catalysts. TRM 2 exhibits the maximum degradation percentages of azo dye under sunlight (99.8 %) irradiation. The optimization studies were conducted, such as the effect of pH, catalyst dosage, and concentration. The optimum condition for photocatalytic degradation was pH - 6.51, TRM dosage - 10 mg, and dye concentration - 5 ppm. The kinetic studies were conducted for the various concentrations (5–20 ppm), and the rate of reaction was determined; it clearly illustrated that the reaction follows a pseudo-first-order kinetics. The enhanced PCA in the TRM 2 was due to the combination of transition/rare-earth metal oxides on the carbon-based material. This transition/rare-earth metal oxide-supported carbon-based nanomaterials (TRM) is practically helpful in degrading environmental pollutants in real-time wastewater under sunlight irradiation.

The study focused on producing and examining the properties of the 2-(((3-mercapto-5-(4-nitrophenyl)-4H-1,2,4-triazol-4-yl)imino)methyl)-4-(((4-mercaptophenyl) diazenyl)phenol) ligand (L) and its complexes with three transition metal ions, namely Ni(II), Co(II), and Cu(II). The ligand was formed through diazotization and coupling reactions between 4-aminobenzenethiol and a coupling Schiff base derived from 1,2,4-triazole. The characterization of the ligand and its metal ion complexes was carried out using analytical techniques such as FTIR, 1H- and 13C-NMR, UV-visible spectroscopy, and thermal analysis (TGA and DTG). Various physical methods were employed to synthesize and analyze the properties of the three mononuclear Co(II), Ni(II), and Cu(II) complexes with the azo-dye Schiff's base ligand. Based on the microanalysis and spectroscopic results, it was determined that the coordination between the azo Schiff base ligand and the central metal ion occurred through the NOS-donating atoms of the ligand. The analysis of the electronic spectra revealed that the synthesized Co(II) and Ni(II) complexes exhibited an octahedral geometry, while the Cu(II) complex had a distorted octahedral geometry. The implications of the finding regarding the octahedral and distorted-octahedral geometries include expanding the structural diversity in coordination chemistry, providing insights into ligand-metal interactions, and understanding the influence of geometry on properties.

In this investigation, Co–, Ni- and Cu-doped ZnO nanoparticles were prepared using precipitation methods. The characterization of the as-prepared nanomaterials was carried out using XRD, FT-IR, DRS, XPS and SEM. The XRD analysis showed that the insertion of foreign metal ions into the matrix of ZnO caused a slight shift of the positions of (100), (002) and (101) diffraction peaks of ZnO towards the lower 2θ, by comparison with pure ZnO. The DRS results showed that Co-doped ZnO nanoparticles absorb wavelengths higher than 400 nm. The estimated band gaps (eV) were 2.48, 3.17 and 3.14 for 10 %Co-ZnO, 10 %Ni-ZnO and 10 %Cu-ZnO respectively. The XPS results showed the existence of two valence states for Co and Ni (Co2+/Co3+ and Ni2+/Ni3+) while Cu exists in the form of Cu2+. The photocatalytic efficiency was evaluated under UV and visible irradiations in aqueous solution using methyl orange (MO) as an organic pollutant probe molecule. The results showed that, under visible light, the MO degradation increased significantly by doping ZnO (10 %Co-ZnO: 33.2 %; 10 %Ni-ZnO: 19.8 % and 10 %Cu-ZnO: 52.5 %) by comparison with undoped ZnO (9.3 %). The important increase in photocatalytic activity observed for the doped ZnO by comparison with pure ZnO, particularly for 10 %Cu-ZnO, has been linked to a synergistic effect of both the band gap narrowing and the increase in the lifetime of photogenerated charge carriers.

The present study investigated the degradation of an aqueous Allura Red AC (AR–AC) solution by activating hydrogen peroxide with bicarbonate using cobalt ion (Co2+) as the catalyst. Four independent variables (H2O2, NaHCO3, Co2+, and dye concentrations) were analyzed in the composite central design (CCD). AR–AC degradation was optimized using the response surface methodology (RSM). Under optimal degradation conditions (41.86 mg/L AR–AC, 5.58 mM H2O2, 2.00 mM NaHCO3, and 9.00 µM Co2+), decolorization > 99.86%, mineralization (CO2 to conversion) of 12.99%, and total nitrogen removal of 51.97% were achieved. The predicted values for the three response variables were consistent with the experimental values, with determination coefficients (R2) greater than 0.9053. Because cobalt ions (Co2+) are a source of water pollution, after oxidation, these were adsorbed on sodium bentonite (Na–Bent), obtaining a final concentration of <0.01 mg/L. Bicarbonate-activated hydrogen peroxide is a potential technology for dye wastewater treatment that operates at an alkaline pH and at ambient temperature. [ABSTRACT FROM AUTHOR]

In recent years, artificial additives, especially synthetic food colorants, were found to demonstrate wider properties compared to their natural equivalents; however, their health impact is still not totally mapped. Our study aimed to determine the long-term (30 and 90 days) exposure effect of one of the commonly used artificial food colorants, tartrazine, on NMRI mice. The applied dose of tartrazine referred to the human equivalent dose for acceptable daily intake (ADI). Further, we evaluated its impact on the transcription of a range of epigenetic effectors, members of the DNA methyltransferase (DNMT) as well as histone deacetylase (HDAC) families. Following the exposure, organ biopsies were collected from the lungs, kidneys, liver, and spleen, and the gene expression levels were determined by real-time quantitative reverse transcription PCR (RT-qPCR). Our results demonstrated significant upregulation of genes in the tested organs in various patterns followed by the intake of tartrazine on ADI. Since DNMT and HDAC genes are involved in different steps of carcinogenesis, have roles in the development of neurological disorders and the effect of dose of everyday exposure is rarely studied, further investigation is warranted to study these possible associations. [ABSTRACT FROM AUTHOR]

The textile industry is expanding globally and is considered the backbone of the world's largest source of foreign exchange. The development of the textile industry has caused environmental contamination due to its dye waste, which is complex and very difficult to resolve with chemical and physical treatments. Azo dye is one of the most widely used dyes in textile and other industries. It is one of the significantly toxic dyes, and when released in water bodies, it causes a serious threat to the environment. A bacterial strain having the potential to degrade a variety of azo dyes such as Congo red (CR), methylene blue (MB), Alizarin Red S (AR), and Remazol Brilliant Blue R (RBBR) was isolated from soil samples in the wood weathering area and further identified and characterized. Ligninolytic microorganisms produce laccase enzymes, lignin peroxidase, manganese peroxidase, and other enzymes that can decolorize dye waste from the textile industry. The research phase was qualitative and quantitative tests of ligninolytic bacteria in the decolorization process using several selected synthetic dyes, antagonism tests, and identification of potential bacteria based on 16S rDNA gene sequences. The L11 isolate showed high performance on CR dye of 82.79%, L1 isolate on dye AR of 40.51%, L7 isolate on dye MB of 38.69%, and L8 isolate on RBBR dye of 30.34%. The L11 isolate with the highest potency was identified as Bacillus paramycoides K7.2 with a similarity of 99.71%. After 7 days of incubation, the quantitative test findings are the same as the qualitative test results, with isolate L11 having the largest clear zone on CR, AR, and RBBR dyes. [ABSTRACT FROM AUTHOR]

In today's industries, a diversity of processes give rise to increasing numbers of non-biodegradable compounds that need to be degraded totally or transformed to other less toxic and/or more biodegradable compounds, before their discharge into the environment. One such compound chosen for this study is Orange II, a representative azo-dye that is widely used and easy to monitor in its degradation. The photo-Fenton process was used under heterogeneous and homogeneous conditions to study several different variables. At the end of this research, a comparative study was carried out between the two types of catalysis. It was observed that better results in primary degradation and mineralization were provided by homogeneous catalysis. The photo-Fenton process takes place effectively under heterogeneous and homogeneous catalysis conditions. The process is much faster under homogeneous conditions than under heterogeneous conditions (99.9 and 24% after 90 min, respectively, especially when only 2 ppm of iron in solution is required). Mineralization was observed through total organic carbon, through the variable C/Co as a function of time during photo-Fenton and Orange II degradation, and the data obtained for the final oxidation capacity are in agreement with the experimental percentages of mineralization. A linear fit was observed using the Chan–Chu kinetic model for heterogeneous and homogeneous catalysis. For heterogeneous catalysis, 56% mineralization was reached whereas the model predicts 63%. Regarding homogeneous catalysis, according to the model, 100% mineralization is reached because (1/σ) takes a value greater than 1 since the model calculates it on infinite time. [ABSTRACT FROM AUTHOR]

Pollution caused by the release of toxic heavy metals into the environment by industrial and farming processes has been regarded as a major problem worldwide. This has attracted a great deal of attention into restoration and remediation. Mercury is classified as a toxic heavy metal which has posed significant challenges to public and environmental health. To date, conventional methods for mercury detection rely on expensive, destructive, complex, and highly specialized methods. Evidently, there is a need to develop systems capable of easily identifying and quantifying mercury within the environment. In this way, organic-based colorimetric chemosensors are gaining increasing popularity due to their high sensitivity, selectivity, cost-effectiveness, ease of design, naked-eye, and on-site detection ability. The formation of coumarin-azo derivative AD1 was carried out by a conventional diazotization reaction with coumarin-amine 1c and N,N-dimethylaniline. Sensor AD1 displayed remarkable visual colour change upon mercury addition with appreciable selectivity and sensitivity. The detection limit was calculated as 0.24 µM. Additionally, the reversible nature of AD1 allowed for the construction of an IMPLICATION type logic gate and Molecular Keypad Lock. Chemosensor AD1 displayed further sensing applications in real-world water samples and towards on-site assay methods. Herein, we describe a coumarin-derived chemosensor bearing an azo (N = N) functionality for the colorimetric and quantitative determination of Hg2+ in organic and aqueous media. [ABSTRACT FROM AUTHOR]

The present study investigated the degradation of an aqueous Allura Red AC (AR–AC) solution by activating hydrogen peroxide with bicarbonate using cobalt ion (Co2+) as the catalyst. Four independent variables (H2O2, NaHCO3, Co2+, and dye concentrations) were analyzed in the composite central design (CCD). AR–AC degradation was optimized using the response surface methodology (RSM). Under optimal degradation conditions (41.86 mg/L AR–AC, 5.58 mM H2O2, 2.00 mM NaHCO3, and 9.00 µM Co2+), decolorization > 99.86%, mineralization (CO2 to conversion) of 12.99%, and total nitrogen removal of 51.97% were achieved. The predicted values for the three response variables were consistent with the experimental values, with determination coefficients (R2) greater than 0.9053. Because cobalt ions (Co2+) are a source of water pollution, after oxidation, these were adsorbed on sodium bentonite (Na–Bent), obtaining a final concentration of

In today’s industries, a diversity of processes give rise to increasing numbers of non-biodegradable compounds that need to be degraded totally or transformed to other less toxic and/or more biodegradable compounds, before their discharge into the environment. One such compound chosen for this study is Orange II, a representative azo-dye that is widely used and easy to monitor in its degradation. The photo-Fenton process was used under heterogeneous and homogeneous conditions to study several different variables. At the end of this research, a comparative study was carried out between the two types of catalysis. It was observed that better results in primary degradation and mineralization were provided by homogeneous catalysis. The photo-Fenton process takes place effectively under heterogeneous and homogeneous catalysis conditions. The process is much faster under homogeneous conditions than under heterogeneous conditions (99.9 and 24% after 90 min, respectively, especially when only 2 ppm of iron in solution is required). Mineralization was observed through total organic carbon, through the variable C/Co as a function of time during photo-Fenton and Orange II degradation, and the data obtained for the final oxidation capacity are in agreement with the experimental percentages of mineralization. A linear fit was observed using the Chan–Chu kinetic model for heterogeneous and homogeneous catalysis. For heterogeneous catalysis, 56% mineralization was reached whereas the model predicts 63%. Regarding homogeneous catalysis, according to the model, 100% mineralization is reached because (1/σ) takes a value greater than 1 since the model calculates it on infinite time.

New composite photocatalysts have been obtained by chemical bath deposition of CdS on top of either nanostructured crystalline ZrO2 or TiO2 films previously deposited on conductive glass FTO. Their morphological, photoelectrochemical and photochemical properties have been investigated and compared. Time resolved spectroscopic, techniques show that in FTO/TiO2/CdS films the radiative recombination of charges, separated by visible illumination of CdS, is faster than in FTO/ZrO2/CdS, evidencing that carrier dynamics in the two systems is different. Photoelectrochemical investigation evidence a suppression of electron collection in ZrO2/CdS network, whereas electron injection from CdS to TiO2 is very efficient since trap states of TiO2 act as a reservoir for long lived electrons storage. This ability of FTO/TiO2/CdS films is used in the reductive cleavage of N=N bonds of some azo-dyes by visible light irradiation, with formation and accumulation of reduced aminic intermediates, identified by ESI-MS analysis. Needed protons are provided by sodium formate, a good hole scavenger that leaves no residue upon oxidation. FTO/TiO2/CdS has an approximately 100 meV driving force larger than FTO/ZrO2/CdS under illumination for azo-dye reduction and it is always about 10% more active than the seconds. The films showed very high stability and recyclability, ease of handling and recovering. [ABSTRACT FROM AUTHOR]

Combination of several films from polymerizable liquid crystal (PLC) into single device system with complex properties faces a fabrication issue due to chemical compatibility and mutual alignment effect of the neighbouring layers. Eco-friendly green technology of high anchoring azo-dye photoalignment layer coating from water solvent provides efficient solution to hinder interlayer interaction of bottom PLC layer avoiding its chemical damage and providing unique photoalignment pattern for top PLC retarder. The advanced possibilities of green technology of photoalignment layers coated from H2O solution are demonstrated through fabrication of achromatic quarter-wave retarder system comprising formation of polimerizable liquid crystal layers on top of one another with arbitrary azimuthal photoalignment direction. The merge of photoaligned PLC retarders into single multi-layer anisotropic structure opens new approach to fabrication of thin-film phase devices with complex optical properties. [ABSTRACT FROM AUTHOR]

In this work, the static and dynamic fluorescence analyses of direct yellow 27 [C25H20Na2O9S3] had been carried out through fluorescence spectroscopic techniques in various polar protic and polar aprotic solvents at room temperature. The prominent emission peak of the molecule observed at 355.84 nm in water, and the Stokes shift of the order of 68.84 nm (Δν = 6741 cm−1) came out. We found the recorded emission peak to be slightly redshifted with increase in polarity of the solvents. The excited-state lifetime measurement of the molecule in different solvents studied and determined that mono-azo direct yellow 27 possessed a lifetime of 12.18 ns in DMSO and 6.8 ns in the water at a concentration of 100 µM. The fluorescence quantum yield (Φf) calculated as 0.41 in water and the impact of different solvents on its value also analyzed. [ABSTRACT FROM AUTHOR]

Flat nonprofiled surface of photoalignment AtA‐2 azo‐dye layer possesses simultaneously low molecular orientation anisotropy and strong azimuthal anchoring energy. We explain how flat surface of alignment layer orients nematic liquid crystal and show the existence of the new photoalignment mechanism based on photo‐induced hole dipole moments in the azo‐dye layer. The dependence of anchoring energy coefficient on the square of dipole moments of the alignment layer and the liquid crystal layer is formulated, grounding the idea of chemical modification of AtA‐2 azo‐dye with molecular dipole moment ~16D to obtain novel high anchoring photoalignment material. The new AtA‐0042 azo‐dye with molecular dipole moment ~27.5D is synthesized and experimentally verified. Strong azimuthal anchoring energy over >1.4 × 10−4 J/m2 is obtained for AtA‐0042 photoalignment material layer with ~40 mJ/cm2 exposure dose. [ABSTRACT FROM AUTHOR]

We deposited homogeneous, thin, yellow-colored films of chitosan (Chi)-N,N-dimethyl-4-(2-pyridylazo)aniline (PADA) dye from an acid Chi–PADA solution by spin-coating on glass substrates. We characterized Chi, PADA, and Chi–PADA films by ATR–FTIR spectroscopy, which revealed a slight shift of 3170 and 3268 cm−1 bands, indicating H-bonding between the chitosan hydroxyl (OH) group and the amine (N) of the PADA pyridine ring. Based on these analyses, it was possible to determine the efficiency of the hydrogen bonds to form a Surface Relief Grating (SRG) on azo-polymer thin film. Moreover, we performed UV–VIS spectroscopy analysis of this film, which showed a broad band extending from 400 to 700 nm, with the maximum occurring at 428 nm. Therefore, we selected, within the absorption band, the 532 nm green laser wavelength to irradiate the azo-polymer films at room temperature. For the first time, natural polymer derivative and dye sample Chi–PADA thin films showed unique photoresponsive behavior under irradiation with two interfering laser beams. This permitted us to generate surface inscription patterning known as an SRG, which we confirmed by atomic force microscopy (AFM) and for which we determined a grating depth up to 50 nm. The present study opens the new possibility of using natural polymer-dye thin films.

In this investigation, Co–, Ni- and Cu-doped ZnO nanoparticles were prepared using precipitation methods. The characterization of the as-prepared nanomaterials was carried out using XRD, FT-IR, DRS, XPS and SEM. The XRD analysis showed that the insertion of foreign metal ions into the matrix of ZnO caused a slight shift of the positions of (1 0 0), (0 0 2) and (1 0 1) diffraction peaks of ZnO towards the lower 2θ, by comparison with pure ZnO. The DRS results showed that Co-doped ZnO nanoparticles absorb wavelengths higher than 400 nm. The estimated band gaps (eV) were 2.48, 3.17 and 3.14 for 10 %Co-ZnO, 10 %Ni-ZnO and 10 %Cu-ZnO respectively. The XPS results showed the existence of two valence states for Co and Ni (Co2+/Co3+ and Ni2+/Ni3+) while Cu exists in the form of Cu2+. The photocatalytic efficiency was evaluated under UV and visible irradiations in aqueous solution using methyl orange (MO) as an organic pollutant probe molecule. The results showed that, under visible light, the MO degradation increased significantly by doping ZnO (10 %Co-ZnO: 33.2 %; 10 %Ni-ZnO: 19.8 % and 10 %Cu-ZnO: 52.5 %) by comparison with undoped ZnO (9.3 %). The important increase in photocatalytic activity observed for the doped ZnO by comparison with pure ZnO, particularly for 10 %Cu-ZnO, has been linked to a synergistic effect of both the band gap narrowing and the increase in the lifetime of photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

• The synthesised Schiff base derived ENB and its metal complexes. • The designed sensor act as efficient-bio-active, selective, stable and linearity. • The MWCNT-[Co(ENB) 2 ]/GCE responses well in the detection of ciplactin. • Synthesised compounds screened for cytotoxicity A549 and antioxidant activities. • Molecular docking exhibits the active site and E-score of synthesized compounds. A Schiff base derivative, 4-{[(E)-{2‑hydroxy-3-[(Z)-1,3-thiazol-2-yldiazeneyl]napthalen-1-yl}methylidene]amino}benzoic acid (ENB) and some of its transition metal complexes were synthesised. The structure of the ENB and its complexes were characterised by NMR, FT-IR, mass spectra, TGA, UV–visible, PXRD and ESR techniques. Physico-chemical data suggest an octahedral geometry nature. Molecular docking for all the synthesised compounds has been performed to predict the binding affinity. The [Ni(ENB) 2 ] exhibited excellent binding score of -284.32 kcal/mol In vitro cytotoxicity activities on lungs cell line A459 exhibited significant IC 50 values and the results indicated that [Co(ENB) 2 ] is a stronger antioxidant agent. Electrochemical detection of bioactive drug ciplactin using a modified electrode, MWCNT-[Co(ENB) 2 ]/GCE showed an excellent sensing ability with a long linear range 10-90 µmol/L, sensitivity 0.4765 µAµM−1cm−2 and its LOD is 3.333 µmol/L in PBS pH 7. Further, the modified electrodehas more stability and less leaching property in the detection system. [Display omitted] [ABSTRACT FROM AUTHOR]

Despite the multidisciplinary standard treatment of glioblastoma (GB) consisting of maximal surgical resection, followed by radiotherapy (RT) plus concomitant chemotherapy with temozolomide (TMZ), the majority of patients experience tumor progression and almost universal mortality. In recent years, efforts have been made to create new agents for GB treatment, of which azo-dyes proved to be potential candidates, showing antiproliferative effects by inducing apoptosis and by inhibiting different signaling pathways. In this study we evaluated the antiproliferative the effect of six azo-dyes and TMZ on a low passage human GB cell line using MTT assay. We found that all compounds proved antiproliferative properties on GB cells. At equimolar concentrations azo-dyes induced more cytotoxic effect than TMZ. We found that Methyl Orange required the lowest IC 50 for 3 days of treatment (26.4684 μM), whilst for 7 days of treatment, two azo dyes proved to have the highest potency: Methyl Orange IC 50 = 13.8808 μM and Sudan I IC 50 = 12.4829 μM. The highest IC 50 was determined for TMZ under both experimental situations. Conclusions: Our research represents a novelty, by offering unique valuable data regarding the azo-dye cyototoxic effects in high grade brain tumors. This study may focus the attention on azo-dye agents that may represent an insufficient exploited source of agents for cancer treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • A triad consisting of two azorubine ligands and sn-tetra(sulfophenyl)porphyrin has been synthesized. • Spectral-luminescent properties of the triad and its components in aqueous media have been studied. • The triad exhibits tunable sensitivity to the medium pH and local viscosity for each specific case. A triad (Az-SnP-Az) consisting of two azorubine ligands (Az) axially bonded to the sulfo-derivative of Sn(IV)-tetraphenylporphyrin [SnP(OH) 2 ] has been synthesized. The triad structure is optimized by quantum chemical calculations and confirmed by a complex of physicochemical methods. The spectral-luminescent properties of the triad and its components in aqueous media have been studied. The sensitivity of the photophysical characteristics of the triad to the concentration-dependent viscosity of the solution has been studied on a model system (binary solvent glycerol-water). It has been established that the resulting triad has the properties of a molecular rotor and exhibits high sensitivity to local viscosity at the Az and SnP absorption maxima. The ability to tune the wavelength of the radiation, allows configuring the created "molecular rotor" to monitor the local viscosity for each specific case. [ABSTRACT FROM AUTHOR]

[Display omitted] • γ-Al 2 O 3 nanowires were successfully synthetized and extensively characterized. • Different amounts of iron were incorporated in order to obtain photoactive catalysts. • Complete decoloration of an azo-dye was achieved after 240 min of irradiation. • Evaluation of different reaction parameters was performed. γ-Al 2 O 3 nanowires (NW) were synthetized and impregnated with different amounts of iron (2, 6 and 10 wt%). Catalysts were further characterized by powder X-ray, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption isotherms, UV–visible diffuse reflectance, temperature-programmed reduction, thermogravimetric analysis, transmission electron microscopy, X-ray photoelectron spectrometry and atomic absorption. The obtained materials were evaluated as heterogeneous photocatalysts in the degradation of azo dye methyl orange as model compound employing a 125 W high-pressure mercury lamp. After 240 min under irradiation the complete decoloration and 69% of mineralization was obtained when Fe6NW was employed. When commercial γ-Al 2 O 3 was employed as support of 6 wt%. of iron and evaluated in photodegradation the final decoloration reached up to only 46%. Reaction parameters such as iron amount, catalyst amount, pH, effect of support and reuses, were evaluated. The photocatalyst was employed for five consecutive reaction cycles with only a 10% of diminish of activity, resulting in an attractive low-cost and benefit in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

We deposited homogeneous, thin, yellow-colored films of chitosan (Chi)-N,N-dimethyl-4-(2-pyridylazo)aniline (PADA) dye from an acid Chi–PADA solution by spin-coating on glass substrates. We characterized Chi, PADA, and Chi–PADA films by ATR–FTIR spectroscopy, which revealed a slight shift of 3170 and 3268 cm−1 bands, indicating H-bonding between the chitosan hydroxyl (OH) group and the amine (N) of the PADA pyridine ring. Based on these analyses, it was possible to determine the efficiency of the hydrogen bonds to form a Surface Relief Grating (SRG) on azo-polymer thin film. Moreover, we performed UV–VIS spectroscopy analysis of this film, which showed a broad band extending from 400 to 700 nm, with the maximum occurring at 428 nm. Therefore, we selected, within the absorption band, the 532 nm green laser wavelength to irradiate the azo-polymer films at room temperature. For the first time, natural polymer derivative and dye sample Chi–PADA thin films showed unique photoresponsive behavior under irradiation with two interfering laser beams. This permitted us to generate surface inscription patterning known as an SRG, which we confirmed by atomic force microscopy (AFM) and for which we determined a grating depth up to 50 nm. The present study opens the new possibility of using natural polymer-dye thin films. [ABSTRACT FROM AUTHOR]

The widespread usage of harmful pulsed laser sources emitting brief but intense radiations implies to search for appropriate and convenient forms of protection. Nonlinear optical nanomaterials can serve this purpose when properly embedded in a solid medium, resulting in nanocomposite passive optical limiting filters. This article focuses on the optical limiting behavior of a series of polymer-dye nonlinear nanocomposites, for which we combined azophloxine, a red azo dye, with two polymer hosts, namely polymethyl methacrylate (PMMA) and polylactide (PLA). In this work, optical filters were produced by chemical synthesis from the bulk. Their linear absorption and transmittance were measured by UV–VIS-NIR spectrophotometry and their thermal examination was done via TGA measurements. The optical limiting properties were characterized using an appropriate custom-made optical setup and the nonlinear absorption coefficients and refractive indices were measured by the Z-scan method. Optical measurements in the nonlinear regime were performed at the wavelength of 1064 nm with nanosecond pulses at a low pulse repetition rate. The nonlinear optical properties resulting from energy dependent transmittance assessments reveal that the dye concentration is of major relevance regarding the PMMA nanocomposites, and to a lesser extend for the PLA based systems. The PLA synthesis concept described in this study offers an easy way to directly attach the dye covalently to the polymer chain. The originality and novelty of this synthesis technique is to be pointed out since it has never been mentioned elsewhere to date. For the various types of nanocomposites investigated, significant differences in the optical limiting response were observed. For instance, it is averred that a significantly higher optical limiting effect results in the systems with the less azo dye concentration and the best optical limiting performance corresponding to a laser protection level of OD = 3.3 was measured for the PLA based system. Besides, the PMMA nanocomposite system exhibits an optical limiting level of OD = 1.9. A molecular model claiming for the dye aggregation in the PMMA nanocomposites is discussed. Two different absorption regimes responsible for the optical limiting action have been identified to be reverse saturable (RSA) – excited state absorption (ESA) on the one hand and multi-photons absorption (MPA) on the other hand. By means of transmittance investigations in an open Z-scan configuration, one could observe the sudden and remarkable changeover from a saturable absorption (SA) regime to a reverse saturable absorption one for high azo dye loads in PMMA. Such transition from SA to RSA has been basically revealed for materials and experimental conditions close to or centered on the resonance of absorption (i.e. around 532 nm). To the author's knowledge, a study in off-resonant conditions (i.e. 1064 nm) was never reported elsewhere to date. Also tracked out by open Z-scan measurements, significantly higher nonlinear absorption coefficients βresulted for the PLA based systems. Similar experiments in a close aperture Z-scan scheme revealed nonlinear refractive indexes in the order of n 2 = - 2.0 X 10 - 15 cm 2 / W for the PMMA nanocomposites and n 2 = - 3.0 X 10 - 15 cm 2 / W for the PLA nanocomposites. [ABSTRACT FROM AUTHOR]