Publications

Highly sensitive and stable phenyl hydrazine chemical sensors based on CuO flower shapes and hollow spheres

Chemical sensors are needed to develop efficient sensing systems with high flexibility, and low capital cost for controlled recognition of analytes. Herein, we report a highly sensitive, low cost, simple chemical sensor based on flower shape and hollow sphere CuO. Following the precipitation process, FESEM images revealed that CuO nanosheets are grown in high density and organized in a proper manner to give a flower shape structure; however, following the hydrothermal method in the presence of urea, the cage like micro structures CuO hollow spheres have been discovered. XRD revealed that the grown CuO has a single-crystalline phase of a monoclinic system. The resistivity of CuO hollow spheres (1.93 × 106 Ω m) is ∼100 times higher than flower shape CuO (2.2 × 104 Ω m). The prepared CuO flower shapes and hollow spheres have been evaluated for the detection and quantification of phenyl hydrazine. The findings indicate that CuO hollow spheres and flowers exhibited good sensitivity (0.578 and 7.145 μA cm−2 mM−1) and a lower limit of detection (LOD = 2.4 mM) with a linear dynamic range (LDR) of 5.0 μM to 10.0 mM and rapid assessment of the reaction kinetics (in the order of seconds). The designed flower shape CuO sensing system is 12 times more sensitive than CuO hollow spheres. To the best of our knowledge, the measured sensitivity ∼ 7.145 μA cm−2 mM−1 of CuO flower shapes is found to be among the highest sensitivity values reported for phenyl hydrazine up to now.

CCDC 1006851: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione

5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione 3 was prepared by Knoevenagel condensation of 3,4di-methoxybenzaldehyde 1 and N,N-diethylthiobarbituric acid 2 in ethanol using piperidine as a base [1,2].[...]

Ultrasensitive and label-free detection of creatine based on CdO nanoparticles: a real sample approach

Low-dimensional cadmium oxide nanoparticles (CdO NPs) were prepared by a facile wet-chemical method, which later electrochemically investigated for the determination of selective creatine and measured the analytical sensor parameters such as sensitivity, limit of detection (LOD), linear dynamic range (LDR), long-term stability, and real-sample validation.

Study of the base-catalysed oxidation of the anti-bacterial and anti-protozoal agent metronidazole by permanganate ion in alkaline medium

Nonlinear Dimensionality Reduction for Visualizing Toxicity Data: Distance‐Based Versus Topology‐Based Approaches

Over the years, a number of dimensionality reduction techniques have been proposed and used in chemoinformatics to perform nonlinear mappings. In this study, four representatives of nonlinear dimensionality reduction methods related to two different families were analyzed: distance-based approaches (Isomap and Diffusion Maps) and topology-based approaches (Generative Topographic Mapping (GTM) and Laplacian Eigenmaps). The considered methods were applied for the visualization of three toxicity datasets by using four sets of descriptors. Two methods, GTM and Diffusion Maps, were identified as the best approaches, which thus made it impossible to prioritize a single family of the considered dimensionality reduction methods. The intrinsic dimensionality assessment of data was performed by using the Maximum Likelihood Estimation. It was observed that descriptor sets with a higher intrinsic dimensionality contributed maps of lower quality. A new statistical coefficient, which combines two previously known ones, was proposed to automatically rank the maps. Instead of relying on one of the best methods, we propose to automatically generate maps with different parameter values for different descriptor sets. By following this procedure, the maps with the highest values of the introduced statistical coefficient can be automatically selected and used as a starting point for visual inspection by the user.

AIE active turn-off fluorescent probe for the detection of Cu 2+ ions

Sensor development of 1,2 Dichlorobenzene based on polypyrole/Cu-doped ZnO (PPY/CZO) nanocomposite embedded silver electrode and their antimicrobial studies

N-Trifluoroacetylated pyrazolines: Synthesis, characterization and antimicrobial studies

1-[(E)-(3,4-Dimethylisoxazol-5-yl)iminomethyl]-2-naphthol

The title Schiff base compound, C(16)H(14)N(2)O(2), has been synthesized by the reaction of 5-amino-3,4-dimethyl-isoxazole and 2-hydr-oxy-1-naphthaldehyde. The dihedral angle between the isoxazole ring and the napthyl ring system is 3.29 (7)°. The mol-ecule adopts an E configuration about the central C=N double bond. Intra-molecular O-H⋯N hydrogen bonding generates an S(6) ring motif. In the crystal structure, π-π inter-actions are observed involving the isoxazole ring and the substituted benzene ring of the naphthyl unit, with centroid-centroid distances of 3.5200 (10) Å.

Trace electrochemical detection of Ni2+ ions with bidentate N,N′-(ethane-1,2-diyl)bis(3,4-dimethoxybenzenesulfonamide) [EDBDMBS] as a chelating agent

Effect of composition of mono/di-hydroxy organic compounds and temperature on the aggregation behavior and physico-chemical properties of polyvinyl alcohol + TTAB mixture

Herein, the aggregation manners of polyvinyl alcohol (PVA) with tetradecyltrimethylammonium bromide (TTAB) in alcohols/diols media containing various concentrations and at several temperatures were performed using the conductivity measurement technique. Different physico-chemical parameters, such as critical micelle concentration (CMC), fraction of bound counter ions (β) and thermodynamic properties (ΔGom, ΔHom, ΔSom, and ΔCom) for the TTAB + PVA mixture in aqueous solutions of EtOH (EtOH), 1-propanol (1-PrOH), ethylene glycol (EG), and propylene glycol (PrG), have been determined. The CMC values were found to undergo a decrease in 1-PrOH in comparison to the values obtained in aqueous media, but in EtOH, the CMC value firstly decreases, touches the lowest point, and then exhibits an upsurge with further increase of the percentage of EtOH. The observed greater CMC values in diols media disclose that the micelle formation of TTAB + PVA mixture is delayed in the manifestation of diols. The CMC values of TTAB + PVA mixture have also been observed to vary with the change of study temperature. The negative values of ΔG0m were obtained for all circumstances suggesting a spontaneous aggregation phenomenon of TTAB + PVA system. The values of ΔH0m and ΔS0m dictate that the PVA molecule interacts exclusively with TTAB through the formation of hydrogen bonding, ion-dipole, and hydrophobic interaction. Furthermore, the standard molar heat capacity (ΔC0m), compensation temperature (Tc), intrinsic enthalpy gain (ΔH0,*m), and the thermodynamic properties of transfer (ΔG0m.tr, ΔH0m.tr. and ΔS0m.tr.) for the studied system were assessed and demonstrated with appropriate explanations.

Anti-bacterial PES-cellulose composite spheres: dual character toward extraction and catalytic reduction of nitrophenol

Polyethersulfone (PES) based hybrid adsorbents were used for the removal of different phenols from aqueous solutions, which are categorized as major aquatic organic pollutants.

Branched Alkylamine–Reduced Graphene Oxide Hybrids as a Dual Proton–Electron Conductor and Organic-Only Water-Splitting Photocatalyst

We report multifunctionalities including the solid electrolytic property, electron conductivity (EnC), and photocatalytic water splitting (PWS) ability of organic-only hybrids obtained by intercalating short and branched-chain alkylamines including methylamine (MA), butylamine (BA), pentylamine (PA), and isomethylbytylamine (IMBA) in reduced graphene oxide (rGO). The alkylamine-rGO hybrids were synthesized by a facile solid-state reduction process. Within the series, IMBA-rGO exhibited high proton conductivity (PrC), EnC, and optimized PWS capacity. The PrC of IMBA-rGO was from 10^-4 to 10^-3 S cm^-1, which is only half an order less than that for pristine GO. The EnC was 1.25 μA/V. Though the PWS performances of MA-rGO, BA-rGO, and PA-rGO were comparatively lower, IMBA-rGO could generate about 1.5 times H₂ compared with that for R-TiO₂. The IR spectra indicate the association of IMBA and GO by chemical bonds. The Raman spectra show the transformation of GO's nonconductive sp³ carbon sites into electron-conductive sp² carbon centers. The thermogravimetric analysis show improved water adsorbing capacity of IMBA-rGO, which resulted in higher PrC. Doping of the nitrogen atom at the graphitic sp² system was confirmed from the presence of pyrrolic N in X-ray photoelectron spectroscopy spectra. The resultant N-type semiconducting behavior is majorly responsible for the PWS process. The powder X-ray diffraction analysis indicates a more flexible interlayer space in IMBA-rGO, which facilitates both the reformation of hydrogen bonds during proton conduction and water dynamics during photocatalysis. The material indicates the possibility of devising graphene-based organic-only multifunctional hybrids.

CCDC 1028227: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Electrochemical Studies of Some Carbazole Derivatives via Cyclic Voltammetry and Convolution – deconvolution Transforms

Three carbazole chromophores derivatives featuring dicyno, cyano, ethyl acetate and dimethyl acetate groups as an acceptor moiety with a ? – conjugated spacer and N-methyl dibenzo[b]pyrole as donor were investigated electrochemically at a platinum electrode in 0.1 mol/L tetraethylammonium chloride (TEACl) in acetonitrile solvent via cyclic voltammetry, convolution – deconvolution transforms and digital simulation techniques. Cyclic voltammetric study revealed that the presence of a single reversible oxidative peak due to two sequential electron transfer (EE scheme) and unidirectional reductive peak which proceed as ECEC mechanism. The electrode reaction pathway, the relevant chemical and electrochemical parameters of the investigated carbazole chromophores were determined using cyclic voltammetry, convolution- deconvolution transforms and chronoamperograms. The extracted electrochemical parameters and the nature of the electrode reaction were verified & confirmed via digital simulation method.

Catalysis by metal–organic frameworks in water

Metal-organic frameworks (MOFs) having a large surface area and porosity as well as a high density of transition metals are increasingly used as heterogeneous catalysts for organic reactions. However, one of the main limitations of various MOFs has been their lack of structural stability that led to an assumption that MOFs are unstable materials, particularly in water or polar solvents. However, since a few years ago the hydrothermal stability of several MOFs such as MIL-101(Cr), MIL-53(Al) and ZIF-8 has been demonstrated and, hence, they can be used as solid catalysts in the aqueous phase. The present review is aimed at showing that there are a sufficiently large number of reports proving that certain MOFs can be used as reusable catalysts in water as the solvent. The use of water as the solvent has considerable advantages from the environmental point of view and affordability. Water can be the solvent of choice for hydrolytic processes, but MOFs have been reported as catalysts in water even for esterifications and C-C couplings. Considering that the synthesis of new MOFs is an active area of research and the flexibility in the selection of transition metals and organic linkers, these materials can be prepared with the required hydrophilicity/hydrophobicity to adapt specifically for catalysis in aqueous phase.

Electrocatalytic Performance of Chemically Synthesized PIn-Au-SGO Composite toward Mediated Biofuel Cell Anode

The proposed work intended to make an intellectual contribution to the domain of green nanotechnology which emphasizes the chemical synthesis of a conducting nanocomposite based on the incorporation of gold nanoparticles (Au) into the redox matrix of polyindole (PIn) along with the subsequent improvement in the overall properties of the composite by the addition of sulfonated graphene oxide (SGO). The bioanode was developed by the deposition of the PIn-Au-SGO nanocomposite with subsequent immobilization of ferritin (Frt) and glucose oxidase (GOx) on the glassy carbon electrode (GC). The successful application of the PIn-Au-SGO nanocomposite toward the development of a ferritin-mediated glucose biofuel cell anode was studied by the electrochemical characterization of the constructed bioanode (GC-PIn-Au-SGO/Frt/GOx) for the bioelectrocatalytic oxidation of glucose. The maximum current density obtained by the modified bioanode was found to be 17.8 mA cm^-2 at the limiting glucose concentration of 50 mM in 0.1 M K₄Fe(CN)₆ at a scan rate of 100 mVs^-1. The lifetime of the concerned bioelectrode when stored at 4 °C was estimated to be 53 days approximately. The appreciable results of the structural and electrochemical characterization of the PIn-Au-SGO based bioelectrode reveal its potential applications exclusively in implantable medical devices.