Gajanan Pandey

Vibrational analysis of substituted anilines, anisoles and anisidines: Part I. Vibrational spectra and normal coordinate analysis of some nitro compounds

Abstract The Fourier transform infrared spectra of o-, m- and p-nitroanilines, o-, m- and p-nitroanisoles and 2-nitro-p-, 4-nitro-o- and 5-nitro-o-anisidines along with the Fourier transform far-infrared spectra of the nitroanilines, p-nitroanisole and the nitroanisidines were recorded. The Raman spectra of m- and p-nitroanilines, p-nitroanisole and nitroanisidines were also measured. A normal coordinate analysis was carried out for the in-plane vibrations of these molecules using a 63-parameter modified valence force field. The force constants were refined in an overlay least-squares technique employing 277 frequencies of the molecules. Unambiguously vibrational assignments were made using potential energy distributions and eigenvectors.

Removal of Cd(II) and Cu(II) from aqueous solution using Bengal gram husk as a biosorbent

AbstractIn the present work, Cicer arietinum husk (Bengal gram husk BGH) has efficiently been utilized for the removal of Cd(II) and Cu(II) from aqueous solutions. Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction and proximate analysis were used to analyse the biosorbent. Batch experiments were conducted to analyse as well as to evaluate the sorption capacity of metal ions. Factors affecting metal ions adsorption, such as contact time, pH, concentration ranges and adsorbent doses were studied. Maximum sorption of Cu(II) was found at pH 5, while for Cd(II), it was achieved at pH 7. From FTIR and NMR results, it has been found that in BGH, –OH group was present in abundance, and participated in metal complex formation in the sorption experiments. The biosorption process was fast enough because equilibrium reached at 120 min, following pseudo-second-order kinetics. The biosorption data fitted well in the Langmuir isotherm model, indicating the m...

Achieving High Ortho Selectivity in Aniline C–H Borylations by Modifying Boron Substituents

High ortho selectivity for Ir-catalyzed C-H borylations (CHBs) of anilines results when B2eg2 (eg = ethylene glycolate) is used as the borylating reagent in lieu of B2pin2, which is known to give isomeric mixtures with anilines lacking a blocking group at the 4-position. With this modification, high selectivities and good yields are now possible for various anilines, including those with groups at the 2- and 3-positions. Experiments indicate that ArylN(H)Beg species are generated prior to CHB and support the improved ortho selectivity relative to B2pin2 reactions arising from smaller Beg ligands on the Ir catalyst. The lowest-energy transition states (TSs) from density functional theory computational analyses have N-H···O hydrogen-bonding interactions between PhN(H)Beg and O atoms in Beg ligands. Ir-catalyzed CHB of PhN(H)Me with B2eg2 is also highly ortho-selective. 1H NMR experiments show that N-borylation fully generates PhN(Me)Beg prior to CHB. The TS with the lowest Gibbs energy was the ortho TS, in which the Beg unit is oriented anti to the bipyridine ligand.

Nucleation temperature-controlled synthesis and in vitro toxicity evaluation of l-cysteine-capped Mn:ZnS quantum dots for intracellular imaging

Quantum dots (QDs), one of the fastest developing and most exciting fluorescent materials, have attracted increasing interest in bioimaging and biomedical applications. The long-term stability and emission in the visible region of QDs have proved their applicability as a significant fluorophore in cell labelling. In this study, an attempt has been made to explore the efficacy of L-cysteine as a capping agent for Mn-doped ZnS QD for intracellular imaging. A room temperature nucleation strategy was adopted to prepare non-toxic, water-dispersible and biocompatible Mn:ZnS QDs. Aqueous and room temperature QDs with L-cysteine as a capping agent were found to be non-toxic even at a concentration of 1500 µg/mL and have wide applications in intracellular imaging.

Fe-EBT Chelate Complex: A Novel Mean for Growth of α-FeOOH and γ-Fe2O3 Nanostructures

Acicular goethite (α-FeOOH) and worm-like maghamite (γ-Fe2O3) nanostructures have been prepared adopting a novel route, using Na2[Fe(HL)2(H2O)2] chelate complex in alkaline medium. It is found that concentration of hydrated Fe(III) ions increased with increasing temperature, which later play a key role in generation of different phases of iron oxide. Phase and morphology of the products are investigated using XRD, FTIR, SEM, and TEM analysis. Using UV–Vis spectra, various electronic transitions of goethite and maghamite particles are examined. Maghamite nanostructures exhibit superparamagnetic property at room temperature. On the basis of experimental observations and analytical data, growth mechanism of the nanostructures is discussed.

Nanoparticles: An Emerging Weapon for Mitigation/Removal of Various Environmental Pollutants for Environmental Safety

Nanotechnology is a recent field of technology and nanoparticle materials are fundamental units that measure within the range 1–100 nm with several types of morphologies. They have exceptional and unique catalytic properties, which are associated with their size and are changed from their bulk materials. These nanoparticle materials are prepared by the various methods such as chemical, physical and biological methods. The prepared nanoparticles are investigated by numerous characterisation techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area analysis, absorbance spectroscopy, photoluminescence spectroscopy. XRD revealed the crystalline nature of the nanoparticles. SEM and TEM images provides information on the morphology and particle size distribution, and BET revealed the surface properties of the nanoparticles. Optical properties are investigated by absorbance and photoluminescence spectroscopic techniques. The effective photo-catalysis of organic toxic pollutants and heavy metals from the environment have been a challenging subject for human health. Much research has explored the environmental behaviour of nanostructured materials for the effective removal of hazardous organic pollutants and heavy metals, existing both in the surface and underground wastewater. The goal of this chapter is to indicate the outstanding removal capability and environmental remediation of nanostructured materials for various toxic organic pollutants and heavy metal ions.

Preparation and photocatalytic activity of TiO2/PPy/GO for the degradation of Rose Bengal and Victoria Blue dye in visible light in aqueous solution

This research work describes a proficient method for synthesis of TiO2/PPy and TiO2/PPy/GO nanocomposites. These nanocomposites were prepared by one-step in-situ deposition oxidative polymerization of pyrrole hydrochloride using ammonium persulphate as an oxidant in the presence of TiO2 nanoparticles (NPs) cooled in an ice bath. The obtained nanocomposites were characterized by X-ray diffraction, transmission electron microscope, scanning electron microscope, UV-Visible, Brunauer– Emmett–Teller, and photoluminescence spectra techniques. The obtained results showed that TiO2 NPs have been encapsulated by PPy with a strong effect on the morphology of TiO2/PPy and TiO2/ PPy/GO nanocomposites. The photocatalytic degradation of Rose Bengal and Victoria Blue dyes were done at different condition viz. concentration of dye, time of illumination, pH, and dose of photocatalyst. The maximum photodegradation of dyes was found at 7 pH, 20 ppm concentration of Victoria Blue and 25 ppm of Rose Bengal dye solution, 800 mg/L for Victoria Blue dye (VB) and 1,600 mg/L for Rose Bengal dye (RB) amount of photocatalyst, and 120 min irradiation of visible light. Kinetics of photodegradation was investigated for VB and RB dye and found first-order kinetics.

Photocatalytic Degradation of Citric Acid in Wastewater in Presence of Visible Light by La:Ni:TiO 2 Nanocomposite

In this study, nanocomposites of La:Ni:TiO 2 nanocomposite was prepared by the co-precipitation method. The material was found in the nano dimension by the SEM and TEM analysis. The rutile and anatase both phases were present in XRD analysis of the synthesized materials. The particle size was found 24 and 82 nm in the case of La:Ni:TiO 2 nanocomposite and pure Titania respectively. The surface area of Titania and La:Ni:TiO 2 nanocomposite were found 6.4 and 43.2 m 2 /g. The band gap energy of Titania and La:Ni:TiO 2 nanocomposite were found 3.2 eV and 3.0 eV respectively. The photodegradation of Citric Acid was investigated at different parameters such as temperature, concentration, pH of the reaction mixture, the dose of photocatalyst and time of illumination of visible light. The photodegradation of Citric Acid occurs 60-90% in presence of La:Ni:TiO 2 nanocomposite, while in presence of titania 10-18%. It is found that photodegradation of Citric Acid follows the first order kinetics.