S. Arul Antony

Structure, morphology and opto-magnetic properties of Bi2MoO6 nano-photocatalyst synthesized by sol–gel method

Abstract Bismuth molybdate (Bi2MoO6) nano-particles (NPs) were synthesized using bismuth nitrate, ammonium molybdate, citric acid and ethyl cellulose by a simple sol–gel method. The structure, morphology, opto-magnetic and photocatalytic properties of the obtained powder were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, high resolution scanning electron microscopy (HRSEM), energy dispersive X-ray (EDX), ultraviolet–visible diffuse reflectance spectra (DRS), photoluminescence (PL) spectra and vibrating sample magnetometer (VSM) techniques. The XRD, FT-IR and EDX results indicate that the resultant powder is pure and single phase crystalline Bi2MoO6 with orthorhombic structure. The HRSEM image shows that the morphology of obtained powder consists with well defined nano-particles structure. The VSM results show superparamagnetic behavior of the obtained nano-particles. The photocatalytic activity of Bi2MoO6 nano-particles was performed. The addition of TiO2 catalyst enhances the photocatalytic activity of Bi2MoO6 nano-particles. The catalysts Bi2MoO6, TiO2 and mixed oxide catalyst Bi2MoO6–TiO2 nano-composites (NCs) were tested for the photocatalytic degradation (PCD) of 4-chlorophenol (4-CP). It is found that the PCD efficiency of Bi2MoO6–TiO2 NCs is higher than that of pure Bi2MoO6 and TiO2 catalysts.

Synthesis, spectral characterization and biological activity of metal(II) complexes with 4-aminoantipyrine derivatives.

Novel metal(II) complexes derived from furfurylidene-4-aminoantipyrine and 2-aminobenzothiazole were synthesized and characterized by spectroscopic (IR, (1)H NMR, UV-Vis., ESR and DART-MS) and other analytical methods. IR spectral studies indicate the binding sites of the ligand with the metal ion. Molar conductance data and magnetic susceptibility measurements provide evidence for monomeric and neutral nature of the complexes. The X band ESR spectrum of the Cu(II) complex at 300 and 77K was recorded. The electrochemical behaviour of the complexes in MeCN at 298 K was studied. Thermal studies of the ligand and its complexes show the presence of coordinated water in the complexes. The grain size of the complex was calculated by Scherrer formula using powder XRD. The surface morphology of the complexes was studied using SEM. The in vitro biological screening of the ligand and its complexes were tested against bacterial species S. aureus, E. coli, K. pneumoniae, P. vulgaris and P. aeruginosa and fungal species A. niger, R. stolonifer, A. flavus, R. bataicola and C. albicans. The DNA binding and cleavage activity of the ligand and its complexes were studied. Super oxide dismutase (SOD) activities of the ligand and its complexes have also been measured.

Thiophene and benzodioxole appended thiazolyl-pyrazoline compounds: Microwave assisted synthesis, antimicrobial and molecular docking studies.

A novel series of thiophene and benzodioxole appended thiazolyl-pyrazoline derivatives have been designed, synthesized and evaluated against different bacteria and fungi. The antimicrobial activity of the synthesized compounds were screened using MIC method and were proved synthesized compounds 7o, 7r and 7t to show good antimicrobial activity against bacteria and fungi. In silico molecular docking studies revealed that all the synthesized molecules showed good binding energy toward the target receptor DNA topoisomerase IV, ranging from -10.42 to -11.66 kcal/mol.

Okra (Abelmoschus esculentus) Plant Extract-Assisted Combustion Synthesis and Characterization Studies of Spinel ZnAl2O4 Nano-Catalysts

Spinel ZnAl2O4 nano-catalysts were synthesized by a simple, economical and eco-friendly microwave irradiation (MIM) and conventional heating methods (CHM), using metal nitrates and Okra (Abelmoschus esculentus) plant extract, which play a dual role of both oxidizing and reducing nature. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray (EDX) and selected area electron diffraction (SAED) pattern results were confirmed that the samples have a single-phase cubic spinel structure with high crystalline nature of ZnAl2O4. Surface morphology of the samples was revealed by high resolution scanning electron microscopy (HR-SEM) and high resolution transmission electron microscopy (HR-TEM) techniques and they are confirmed particle-like structure with grain size below 50 nm. The optical band gap (Eg) was measured using Kubelka-Munk model by UV-Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) and the Eg value is higher for MIM product than CHM, due to the smaller particle size of ZnAl2O4-MIM. The magnetic property of the samples was determined by vibrating sample magnetometer (VSM) and showed a superparamagnetic behavior. Spinel ZnAl2O4 nano-catalysts are magnetically recyclable and could be reused with no significant loss in catalytic activity. Both the samples were successfully tested as catalysts for the conversion of alcohols into respective carbonyl compounds using H2O2 (as oxidant) and acetonitrile (as a solvent) system. It was found that the ZnAl2O4-MIM nanocatalysts show best performance of conversion of alcohols into a carbonyl compounds than that of ZnAl2O4-CHM, due to the smaller particle size and higher surface area of ZnAl2O4-MIM samples.

Magnetically Separable MnxZn1-xFe2O4; (0.0 ≤ x ≤ 0.5) Nanostructures: Structural, Morphological, Opto-Magnetic, and Photocatalytic Properties

Mn2+ doped ZnFe2O4 nanocrystals have been successfully synthesized by one-pot autocombustion method. The synthesized MnxZn1-xFe2O4 nanocrystals were characterized by XRD, FT-IR, HR-SEM, TEM, EDX, BET, DRS, PL, and VSM. The results indicated that the prepared spinel MnxZn1-xFe2O4 nanocrystals showed high crystallinity and uniform size distribution with particle-like morphologies. The present study leads to enhance the photocatalytic activity of MnxZn1-xFe2O4 with the addition of TiO2. Having established that spinel MnxZn1-xFe2O4 was photocatalytically active, the mixed oxide catalysts of MnxZn1-xFe2O4 -TiO2 were also tested for the photocatalytic degradation of 4-chlorophenol.

Synthesis, Spectral Characterization, and Antimicrobial Activities of Schiff Base Complexes Derived From 4-Aminoantipyrine

ABSTRACT Novel cobalt (II), nickel (II), copper (II), and zinc (II) complexes were synthesized from Schiff base ligand derived from 4-aminoantipyrine, vanillin, and o-anisidine. The structural features were derived from their elemental analysis, molar conductance, magnetic measurements, and various spectroscopic techniques such as infrared, ultraviolet visible, nuclear magnetic resonance, and electron paramagnetic resonance spectroscopy. Antimicrobial screening tests were performed against bacteria and fungi. The comparative study of the minimum inhibitory concentration values of the Schiff base and its metal complexes indicate that the metal complexes exhibit greater antimicrobial activity than the free ligand.

Preparation and Characterizations of PVP–TiO 2 NPs Calcined at 500, 600 and 700 °C by the Hydrothermal Method and Their Properties

The effect of the crystalline phase PVP encapsulated titanium dioxide (TiO2) nanoparticles (NPs) to optimize the optical properties and photocatalytic activity were comparatively investigated at different calcination temperatures. The synthesized products were characterized using instrumental techniques, such as powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscope, energy dispersive X-ray, ultraviolet–visible (UV–visible), photoluminescence (PL) and vibrating sample magnetometer. The functional groups were identified by the FT-IR analyses. XRD result showed that the anatase and rutile phase structure of TiO2 NPs was confirmed. The spherical shaped morphology is predicted by the SEM analysis. The optical properties of the TiO2 NPs were studied by the UV–visible and PL analysis. The magnetic behavior of the TiO2 NPs was studied. Photocatalytic activity of TiO2 NPs was tested by the degradation of MeB dye under UV light irradiation. In addition, the chemical oxygen demand removal follows the photo degradation in behaviour was observed.

Enhanced catalytic activity, facile synthesis and characterization studies of spinel Mn–Co aluminate nano-catalysts

Undoped and Mn2+ doped CoAl2O4 (MnxCo1-xAl2O4; x = 0.0 to 1.0) spinel nanoparticles were successfully synthesized by a microwave heating method using glycine as the fuel. X-ray powder diffraction (XRD) was confirmed the cubic spinel structure. The average crystallite size of the samples was found to be in the range of 16.46 nm to 20.25 nm calculated by Scherrers formula. The nano-sized particle-like morphology of the samples was confirmed by high resolution scanning electron microscopy (HR-SEM) and transmission electron microscopy (HR-TEM) analysis. Energy dispersive X-ray (EDX) results showed the pure form of spinel aluminate structure. The band gap energy (Eg) of pure CoAl2O4 was estimated to be 3.68 eV from UV-Visible diffuse reflectance spectroscopy (DRS), and the Eg values increased with increase of Mn2+ ions, due to the smaller grain size. The magnetic hysteresis (M-H) loop showed the superparamagnetic nature, and the magnetization and coercivity values increased with increasing Mn2+ ions, which was confirmed by vibrating sample magnetometer (VSM). All compositions of the nano-catalysts were tested as catalyst successfully for the conversion of benzyl alcohol into benzaldehyde and observed good catalytic activity.

Selective and efficient detection of picric acid among other nitroaromatics by NIR fluorescent cyanine chemosensors

Designed and synthesized a fluorescent probe composed of a Hemi cyanine dye bearing conjugated N, N-dimethyl amino benzaldehyde based fluorophore C1 and C2 as a new visible and near-infrared chemo dosimeter type sensor on highly sensitive and selective chemosensors. The color change and quenching of the dye emission are selective detections of picric acid at nanomolar concentration is accomplished in water medium without having any interference from other NACs. The protonation and deprotonation between N,N-dimethylaniline, and N,N-diethyl aniline units will prompt to the changes in the targeted ICT molecules and the emission response can be detected on distinct NAC. The dyes C1 and C2 set out towards NACs was explored in the THF-H2O medium by UV-vis and fluorescence spectra situated around 560 nm with high molar absorption coefficient. NMR spectroscopic titrations in DMSO‑d6 for affirming the interface between the picric acid with C1 1H NMR was utilized to confirm our proposed mechanism. The as-synthesis of cyanine dyes C1 and C2, involves condensation reaction between (1.0 equiv) of 1,1,2,3-tetramethyl-1H-benzo[e]indol-3-ium iodide 2 with (1.1 equiv.) p-N,N-dimethyl amino benzaldehyde, and catalytic amount of piperidine in ethanol continued by reflux for 7 h under idle states, in this way giving a facile, convenient and minimal effort strategy for detection of picric acid in solution and in contact mode.

Structural, Morphological and Optical Properties of ZnO, ZnO:Ni2+ and ZnO:Co2+ Nanostructures by Hydrothermal Process and Their Photocatalytic Activity

ZnO, ZnO:Ni2+ and ZnO:Co2+ nanoparticles (NPs) were prepared via hydrothermal process. The synthesized samples were characterized by using various techniques such as, FT-IR, powder XRD, SEM-EDX, TEM-SAED, UV–Visible, PL and BET. The as-synthesized ZnO, ZnO:Ni2+ and ZnO:Co2+ NPs exhibit strong physicochemical properties including in structural, surface morphology, chemical composition, surface area, optical and photocatalytic activity were comparatively investigated as function of Ni2+ and Co2+ doping. UV–Visible absorption spectra exhibit blue shifted in absorption edge of ZnO, ZnO:Ni2+ and ZnO:Co2+ NPs compared to bulk counterparts. The photocatalytic activity of the ZnO, ZnO:Ni2+ and ZnO:Co2+ NPs have been evaluated by monitoring the degradation of MeB and RhB dyes under UV light irradiation. In degradation efficiency, 84 and 93% of the MeB and RhB dyes is degraded in the presence of the ZnO:Ni2+ and ZnO:Co2+ photocatalyst under optimum experimental conditions. The rate of de-coloration of MeB and RhB dyes are detected by UV–Visible absorption spectroscopy and organic dye mineralization is confirmed by table of carbon study. In addition, the mechanism of the photocatalytic degradation of MeB and RhB dyes has been briefly discussed.