Divya Pratap Singh

A binuclear Mn(II) complex as an efficient catalyst for transamidation of carboxamides with amines

A binuclear Mn(II) complex has been synthesized and characterized by different structural methods. The complex contains two unique oxo-bridged metal centres and has been explored as an excellent catalyst for transamidation of carboxamides with amines under solvent-free conditions.

Removal of Zn(II) from water by adsorption on China clay

Abstract The efficiency of china clay as an adsorbent for the removal of Zn(II) from water has been determined at different concentrations, temperatures and pH of the solutions. The kinetic studies of adsorption indicate the process to be diffusion controlled and the intraparticle transport of Zn(II) within the pores of china clay is found to be the rate limiting step. Equilibrium data at different temperatures follow Langmuir model of adsorption. Thermodynamic parameters for the present system indicates spontaneous and endothermic nature of adsorption. The maximum removal (95%) is observed at pH 8.0 and temperature 40°C with initial concentration 1.53 × 10‐4M. The variation in adsorption with pH has been explained on the basis of surface ionisation and complexation.

Synthesis, structural investigations and corrosion inhibition studies on Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-amino-benzoic acid (phenyl-pyridin-2-yl-methylene)-hydrazide

Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-amino-benzoic acid (phenyl-pyridin-2-yl-methylene)-hydrazide (Habph) have been synthesized. The complexes were characterized by different physico-chemical and spectral studies viz. molar conductance, magnetic susceptibility measurements, electronic, IR and NMR spectra. The molecular structures of the ligand Habph and its Mn(II), Ni(II), Cu(II), Zn(II) complexes were further confirmed by single crystal X-ray diffraction technique. The Habph acts as a monobasic tridentate ligand coordinating through pyridyl-N, azomethine-N and enolate-O atoms with metal ions. Magnetic moments and electronic spectral studies suggest a high spin octahedral geometry for all the complexes. The ligand molecule exhibits a Z molecular conformation about the >CN– bond, whereas the metal complexes show E-configuration in their single crystal structures. The presence of inter- and intra-molecular H-bonding and various C–H⋯π interactions stabilize the molecular structure of the metal complexes. The structure of the Co(II) complex has been satisfactorily modeled by density functional theory (DFT) and time dependent-DFT (TD-DFT) calculations. The results of electrochemical impedance spectroscopy (EIS) and adsorption behavior of the ligand and metal complexes show appreciable corrosion inhibition efficiency for mild steel in a 1 M HCl medium. The metal complexes show a better inhibition effect than the ligand.

Blasting side effects - Investigations in an opencast coal mine in India

Field investigations were conducted in a potential opencast coal mine in India with a view to optimizing blast patterns for controlling ground vibration, sound pressure level and fly rock within safe and tolerable limits. Blasting was performed in all operating benches i.e., alluvium, sandstone, shale, coal and blast vibrations were monitored on the alluvial soil present in the vicinity of the mine. It was observed that in all the blasting rounds, low frequency ground vibrations were generated. Further investigations were carried out by recording structural response to ground vibration on single and double storied buildings. It was observed that the ground vibrations were amplified by structures themselves, as much as 2.0 to 5.6 times

Fly ash for the treatment of Zn(II) rich effluents

SummaryThe ability of fly ash to remove Zn(II) from water by adsorption has been tested at different concentrations, temperatures and pH of the solution. It was found that low adsorbate concentration, small particle size of adsorbent and higher temperature favoured the removal of Zn(II) from aqueous solution. The Langmuir isotherm was used to represent the equilibrium data at different temperatures. The apparent heat of adsorption has been found to be 17.325 Kcal mol−1, which indicates the process to be endothermic. The uptake of Zn(II) is diffusion controlled and the mass transfer coefficient is 3.56 × 10−5cm s−1.The maximum removal was noted at pH 7.5.

Synthesis, thermal studies and spectral characterization of Co(II), Ni(II), Cu(II), and Zn(II) complexes with some polymeric diacetyl acyldihydrazone ligands

AbstractTwo polymeric ligands, diacetyl oxaloyldihydrazone (DODH), diacetyl malonoylhydrazone (DMDH) and their Co(II), Ni(II), Cu(II) and Zn(II) complexes were synthesized and characterized by elemental analyses, IR, mass, 1H & 13C NMR, ESR and electronic spectral studies. The ligands and their complexes are highly insoluble in water and common organic solvents and decompose at high temperature. The metal atoms are embedded between two polymeric chains of the organic ligands and the monomeric unit of the polymeric chain behaves as a neutral bidentate ligand and coordinate through two >C=N groups to different metals as indicated by 1H & 13C NMR and IR spectral studies. The molecular weights determined by 1H NMR and mass spectral studies suggest oligomeric nature of the ligands and their Zn(II) complexes. The magnetic susceptibility measurements and electronic spectral studies indicate a square planar geometry around the metal ion in Co(II) and Ni(II) complexes. Electronic and ESR spectral studies for Cu(II) complexes suggest a distorted octahedral stereochemistry around the metal atom and 2B1g as the ground state. Thermal studies (TGA and DTA) of some of the complexes in inert atmosphere show a multi-step exothermic decomposition of the bonded organic ligand at high temperature and metal (II) chloride as the end product.

Synthesis, characterization and biocidal activity of some transition metal(II) complexes with isatin salicylaldehyde acyldihydrazones.

Cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes with two new unsymmetrical ligands, isatin salicylaldehyde oxalic acid dihydrazide (isodh) and isatin salicylaldehyde malonic acid dihydrazide (ismdh) were synthesized and characterized by elemental analyses, electrical conductance, magnetic moments, electronic, NMR, ESR and IR spectral studies. The isodh acts as a dibasic tetra dentate ligand bonding through two >C=N-, a deprotonated phenolate and deprotonated indole enolate groups to the metal. The ismdh ligand shows monobasic tetra dentate behaviour in bonding with metal ion through two >C=N-, indole >C=O and a deprotonated phenolate group. The electronic spectral data suggest 4-coordinate square planar geometry for Co(II), Ni(II) and Cu(II) complexes of isodh, whereas, 6-coordinate octahedral structure for the ismdh complexes. The ESR studies also indicate a square planar and distorted octahedral environment around Cu(II) for isodh and ismdh complexes, respectively. Most of the metal complexes show better antifungal activity than the standard and a significant antibacterial activity against various fungi and bacteria.

UV-B Radiation Stress Causes Alterations in Whole Cell Protein Profile and Expression of Certain Genes in the Rice Phyllospheric Bacterium Enterobacter cloacae.

Among the different types of UV radiation, UV-B radiation (280-315 nm) has gained much attention mainly due to its increasing incidence on the Earth’s surface leading to imbalances in natural ecosystems. This study deals with the effects of UV-B radiation on the proteome and gene expression in a rice phyllospheric bacterium, Enterobacter cloacae. Of the five bacteria isolated from rice leaves, E. cloacae showed the highest level of resistance to UV-B and total killing occurred after 8 h of continuous exposure to UV-B. Reactive oxygen species were induced by UV-B exposure and increased with increasing duration of exposure. Protein profiling by SDS-PAGE and 2-dimensional gel electrophoresis (2-DE) revealed major changes in the number as well as expression of proteins. Analysis of 2-DE gel spots indicated up/down-regulation of several proteins under the stress of UV-B radiation. Thirteen differentially expressed proteins including two hypothetical proteins were identified by MALDI-TOF MS and assigned to eight functional categories. Both the hypothetical proteins (gi 779821175 and gi 503938301) were over-expressed after UV-B irradiation; gi 503938301 was characterized as a member of FMN reductase superfamily whereas gi 779821175 seems to be a structural protein as it did not show any functional domain. That the expression of certain proteins under UV-B stress is indeed up-regulated was confirmed by qRT-PCR. Transcript analysis of selected gene including genes of hypothetical proteins (cp011650 and cp002886) showed over-expression under UV-B stress as compared to untreated control cultures. Although this study deals with a limited number of proteins, identification of differentially expressed proteins reported herein may prove useful in future studies especially for assessing their significance in the protection mechanism of bacteria against UV-B radiation stress.

A binuclear Cu(I) complex as a novel catalyst towards the direct synthesis of N-2-aryl-substituted-1,2,3-triazoles from chalcones

A binuclear Cu(I) complex containing a N′,N′-bis{(1H-indol-3-yl)methylene}oxalohydrazide (H2bioh) ligand has been synthesized and characterized. The molecular structures of the synthesized compounds have been determined by single crystal X-ray diffraction. The crystal structures are stabilized by inter- and intra-molecular π–π stacking and C–H⋯π interactions. The Cu(I)-complex has successfully been employed as an efficient catalyst for one-pot operation involving the azide–chalcone click reaction and subsequent arylation has been developed. The complex exhibits excellent catalytic activity with significantly low catalyst loading. The overall process is insensitive to air and moisture and can be manipulated under ambient temperature with operational ease.

Rab11 Plays an Indispensable Role in the Differentiation and Development of the Indirect Flight Muscles in Drosophila

Rab11, an evolutionary conserved, ubiquitously expressed subfamily of small monomeric GTPase has been known to regulate diverse cellular and developmental events, by regulating the exocytotic and transcytotic events inside the cell. Our studies show that Rab11 regulates Drosophila adult myogenesis by controlling proliferation and differentiation of the Adult muscle precursors (AMPs). Blocking Rab11 in the AMPs, which fuse to form the Indirect Flight Muscles (IFMs) of fly, renders flies completely flightless and non-viable. The indirect flight musculature, comprising of the differentially patterned dorsal longitudinal muscles (DLMs) and dorsal ventral muscles (DVMs), is affected to different extents. Abrogating or knocking down normal Rab11 function results in severely disrupted IFMs. DLMs forming from larval templates are reduced in number along with a significant reduction in their fibre size. The de novo developing DVMs are frequently absent. The DLMs in Rab11 hypomorphs are highly reduced, showing as a small constricted mass in one half of the thorax. Further, Rab11 function is essential for growth of these muscles during later half of adult myogenesis, as down regulation of Rab11 in IFMs results in degenerated muscles and broken fibres. Finally, we show that loss of Rab11 activity in the AMPs result in acquisition of migratory characteristic of myoblast as they show cellular protrusion at their polar ends accompanied with loss of cell-cell contacts. Our data provide the first evidence of a trafficking protein playing an indispensable role in regulating early stages of adult muscle development.