S. Muthamizh

Synthesis and characterization of chromium(III) Schiff base complexes: Antimicrobial activity and its electrocatalytic sensing ability of catechol

A series of acyclic Schiff base chromium(III) complexes were synthesized with the aid of microwave irradiation method. The complexes were characterized on the basis of elemental analysis, spectral analysis such as UV-Visible, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopies and electrospray ionization (ESI) mass spectrometry. Electrochemical analysis of the complexes indicates the presence of chromium ion in +3 oxidation state. Cr (III) ion is stabilized by the tetradentate Schiff base ligand through its nitrogen and phenolic oxygen. From the spectral studies it is understood that the synthesized chromium(III) complexes exhibits octahedral geometry. Antimicrobial activity of chromium complexes was investigated towards the Gram positive and Gram negative bacteria. In the present work, an attempt was made to fabricate a new kind of modified electrode based on chromium Schiff base complexes for the detection of catechol at nanomolar level.

Synthesis, growth and photoluminescence behaviour of Gd2O2SO4:Eu3+ nanophosphors: the effect of temperature on the structural, morphological and optical properties

Gd2(SO4)3·8H2O, Gd2O2SO4, and Gd2O2SO4:Eu3+ nanoparticles have been synthesized in the presence of Gd3+ ions and sodium dodecyl sulphate (SDS) by the simple complexation-thermal decomposition (CTD) method. The structural analysis, growth mechanism and optical properties of the Gd2(SO4)3·8H2O, and Gd2O2SO4 are described by the diffraction pattern, functional group analysis, Raman, morphology, elemental analysis, and absorbance spectra. The most intriguing factor was that the Gd2O2SO4 nanoplates are in the range of 42–50 nm without adding any external stabilizer. The results revealed that the Gd2O2SO4 nanoparticles with an orthorhombic structure have a band gap of 3.12 eV. Furthermore, Gd2O2SO4 shows an intense red photoluminescence associated with the 5D0 → 7F2 transition in the presence of Eu3+. The results suggest that the Gd2O2SO4:Eu3+ nanophosphors, may have a beneficial approach in the field of biomedical application as luminescent probe/labels.

Manganese sesquioxide to trimanganese tetroxide hierarchical hollow nanostructures: effect of gadolinium on structural, thermal, optical and magnetic properties

Various hollow manganese oxide (bixbyite Mn2O3 and hausmannite Mn3O4) nanoparticles (NPs) with different morphologies were obtained from a single precursor, manganese oxalate (MnC2O4). To synthesize a Mn3O4 stacked nanostructure rather than coral-like Mn2O3 nanospheres, as synthesized MnC2O4 was thermally decomposed at 700 °C in the presence of Gd3+, through the oriented arrangement mechanism. The formation process and structural variation arising from varying the thermal treatment (450 °C and 700 °C) and the cationic dopant Gd3+ were analyzed by FTIR, TGA, and XRD. The unexpected size reduction, and significant physicochemical properties were analyzed using various techniques such as FESEM coupled with EDAX, HR-TEM, DRS-UV-vis, EPR, EIS and VSM. The addition of gadolinium induces particle size reduction and a phase transition from cubic Mn2O3 to tetragonal Mn3O4, which leads to the suppression of the electrical conductivity, and changes in the optical band gap. The prepared Mn3O4 nanocrystals exhibit ferromagnetic behavior below Tc ≈ 45 K and weak paramagnetic behavior at room temperature.

Copper vanadate nanoparticles: synthesis, characterization and its electrochemical sensing property

Copper vanadate (Cu2V2O7) nanoparticles were synthesized by a simple thermal decomposition method. The synthesized copper vanadate nanorods were characterized by X-ray diffraction analysis, and it is found that the synthesized sample belongs to monoclinic Cu2V2O7. Fourier transform infrared spectroscopy (FT-IR) confirms the formation of Cu–O bond in the sample. Ultraviolet–visible (DRS-UV–visible) spectroscopy and photoluminescence spectroscopy reveals the optical property of the Cu2V2O7 nanoparticles. The nanobar-like morphology was confirmed by both scanning electron microscopy and high resolution transmission electron microscopy. Further, the electrochemical sensing behavior of Cu2V2O7 nanoparticles was investigated by cyclic voltammetry using lidocaine as an analyte. The electrochemical sensing experiment suggests that the Cu2V2O7 nanoparticles will become a potential candidate in the field of drug sensor.

Polyaniline Nanorods: Synthesis, Characterization, and Application for the Determination of para-Nitrophenol

ABSTRACT A para-nitrophenol sensor based on a 5-sulfosalicylic acid doped polyaniline nanorods modified glassy carbon electrode is reported. The formation of 5-sulfosalicylic acid doped polyaniline was characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electroactivity of the 5-sulfosalicylic acid doped polyaniline nanorods was studied by cyclic voltammetry and differential pulse voltammetry and high response was observed for the reduction of para-nitrophenol. The calibration curve for para-nitrophenol was linear from 6.7 × 10−6 M to 112.1 × 10−6 M. The sensitivity and limit of detection were 24 nA µM−1 and 3.2 × 10−6 M, respectively. The sensor was simple, inexpensive, and employed for the determination of para-nitrophenol in tap water with recoveries from 97.6 to 101.0%.

Solid state synthesis of copper tungstate nanoparticles and its electrochemical detection of 4-chlorophenol

Copper tungstate (CuWO4) nanoparticles were prepared by Solid state synthesis. The CuWO4 nanoparticles were synthesized by reacting 1:1 mole ratio of copper chloride and sodium tungstate. The XRD pattern reveals that the synthesized CuWO4 has anorthic (triclinic) structure. In addition, the average grain size, lattice parameter values were also calculated using XRD data. The FT-IR analysis confirm the presence of Cu-O and W-O bonds in CuWO4 nanoparticles. The electrochemical sensing behavior of CuWO4 nanoparticles towards 4-chlorophenol was investigated using cyclic voltammetry.

Implementation of oligonucleotide-gated supports for the electrochemical detection of Ochratoxin A

Abstract We report herein the design a hybrid material for the recognition of Ochratoxin A (OTA) by using an aptamer gated-material able to release electroactive species, which can be measured using differential pulse voltammetry. Mesoporous silica nanoparticles loaded with Methylene Blue and capped with an OTA aptamer were prepared and characterised. A highly selective and sensitive response due to the displacement of the capping aptamer in the presence of OTA and subsequent MB release was found in aqueous media. Finally, the possible use of the gated material for the detection of OTA in a real matrix was also explored.

Molybdenum oxide nanocubes: Synthesis and characterizations

Molybdenum oxide nanoparticles were prepared by Solid state synthesis. The MoO3 nanoparticles were synthesized by using commercially available ammonium heptamolybdate. The XRD pattern reveals that the synthesized MoO3 has orthorhombic structure. In addition, lattice parameter values were also calculated using XRD data. The Raman analysis confirm the presence of Mo-O in MoO3 nanoparticles. DRS-UV analysis shows that MoO3 has a band gap of 2.89 eV. FE-SEM analysis confirms the material morphology in cubes with nano scale.

MnMoO4 nanolayers : Synthesis characterizations and electrochemical detection of QA

MnMoO4 nanolayers were prepared by precipitation method. The MnMoO4 nanolayers were synthesized by using commercially available (CH3COO)2Mn.4H2O and Na2WO4.2H2O. The XRD pattern reveals that the synthesized MnMoO4 has monoclinic structure. In addition, lattice parameter values were also calculated using XRD data. The Raman analysis confirm the presence of Mo-O in MnMoO4 nanolayers. DRS-UV analysis shows that MnMoO4 has a band gap of 2.59 eV. FE-SEM and HR-TEM analysis along with EDAX confirms the material morphology in stacked layers like structure in nano scale. Synthesized nanolayers were utilized for the detection of biomolecule quercetin (QA).MnMoO4 nanolayers were prepared by precipitation method. The MnMoO4 nanolayers were synthesized by using commercially available (CH3COO)2Mn.4H2O and Na2WO4.2H2O. The XRD pattern reveals that the synthesized MnMoO4 has monoclinic structure. In addition, lattice parameter values were also calculated using XRD data. The Raman analysis confirm the presence of Mo-O in MnMoO4 nanolayers. DRS-UV analysis shows that MnMoO4 has a band gap of 2.59 eV. FE-SEM and HR-TEM analysis along with EDAX confirms the material morphology in stacked layers like structure in nano scale. Synthesized nanolayers were utilized for the detection of biomolecule quercetin (QA).