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Gajbhiye V.T.,Indian Agricultural Research Institute | Gupta S.,Indian Agricultural Research Institute | Mukherjee I.,Indian Agricultural Research Institute | Singh S.B.,Indian Agricultural Research Institute | And 3 more authors.
Bulletin of Environmental Contamination and Toxicology | Year: 2011

Persistence of azoxystrobin was studied in/on grapes when applied @ 150 g ai ha -1 (recommended dose) and 300 g ai ha -1 (double the recommended dose) in three grapes growing states of India, namely Karnataka, Maharashtra and Tamil Nadu, in the year 2006-2007. A total of five sprays were given at an interval of about 15 days. Grapes and soil samples were collected after 5th spray, extracted and analysed by gas chromatography using electron capture detector. Half life of azoxystrobin on grapes varied from 5.4 to 11.2 days. Residues of azoxystrobin were much below the prescribed MRL (0.5 mg kg -1) after 21 days. The dissipation of azoxystrobin in soil followed first order rate kinetics with an average half life of 8.1 days at the recommended dose of application. © 2010 The Author(s).

Panini P.,Indian Institute of Science | Shukla R.,Indian Institute of Science | Mohan T.P.,Rallis India Ltd. | Vishalakshi B.,Mangalore University | Chopra D.,Indian Institute of Science
Journal of Chemical Sciences | Year: 2014

In the present study, we have prepared and structurally characterized a derivative of 1,2,4 triazoles, namely 3-(4-fluoro-3-phenoxyphenyl)-1-((4-methylpiperazin-1-yl)methyl)-1H-1,2,4-triazole-5-thiol (T-1) via single crystal X-ray diffraction. The crystal structure was observed to be stabilized by the presence of various intermolecular interactions in the crystalline solid such as O-H ⋯S, C-H ⋯F, C-H ⋯S, C-H ⋯N, C-H ⋯O, C-H ⋯π, lp⋯π and π⋯π intermolecular interactions. The interaction energy of these interactions was evaluated through PIXEL method with decomposition of the total energy into the coulombic, polarization, dispersion and repulsion contribution. The study of the nature of H-bonds with sulfur reveals that stabilization due to contribution from polarization plays a significant role. It is noteworthy that the presence of the solvent molecules in the crystal structure were observed to provide stabilization to an otherwise destabilized molecular pair (comprising of two molecules of 1,2,4 triazoles in the asymmetric unit). © 2014 Indian Academy of Sciences.

Hosmani R.S.,Syngenta | Nayak S.P.,Mangalore University | Kumar Y.,Rallis India Ltd.
Quality Assurance and Safety of Crops and Foods | Year: 2012

Introduction: Kresoxim-methyl is a broad spectrum fungicide used for controlling sheath blight and blast in paddy, also downy and powdery mildew diseases in grapes. Objectives: A supervised field trial consisting of two experiments viz. soil application and foliar application was conducted in order to study the uptake, distribution, translocation and metabolism of kresoxim-methyl in paddy, treated at the rates of 250 and 500 g a.i. ha-1. Methods: Depending on the crop growth and stage (40, 60, 80 and 110 days after transplanting), different plant parts like foliage, shoot, roots, panicles, straw and grain, along with soil, were sampled and analysed using liquid chromatography tandem mass spectrometry for parent compound kresoxim-methyl and its metabolites. Results: The results of the study revealed that there was little translocation of residues of kresoxim-methyl and its acid metabolite to various plants parts, i.e. foliage, roots, soil, shoot and panicle, and very little to straw and grains. Conclusion: The major route of metabolism was hydrolysis with formation of acid metabolite. © 2012 Blackwell Publishing Ltd.

Shukla R.,Indian Institute of Science | Mohan T.P.,Rallis India Ltd. | Vishalakshi B.,Mangalore University | Chopra D.,Indian Institute of Science
CrystEngComm | Year: 2014

In the present study, we have synthesized and characterized two biologically active 1,2,4-triazole derivatives, a fluoro derivative, namely (E)-3-(4-fluoro-3-phenoxyphenyl)-4-((4-fluorobenzylidene)amino) -1-(morpholinomethyl)-1H-1,2,4-triazole-5(4H)-thione (TRZ-1), and a chloro derivative, namely (E)-4-((4-chlorobenzylidene)amino)-3-(4-fluoro-3- phenoxyphenyl)-1-(morpholinomethyl)-1H-1,2,4-triazole-5(4H)-thione (TRZ-2), via single crystal and powder X-ray diffraction. The chloro derivative crystallizes in an anhydrous form (TRZ-2A) and a solvated one (TRZ-2B) due to the presence of a toluene molecule in the crystal. This solvatomorphic behavior has been studied in detail using different thermal techniques, namely DSC and TGA, combined with hot stage microscopy (HSM). All of the three crystal structures show the presence of different intermolecular interactions of the type C-H⋯O, C-H⋯SC, C-H⋯π, C-H⋯X (X = -F, -Cl), π⋯π and lp⋯π interactions. The fingerprints for all these interactions were evaluated using Hirshfeld surfaces. The nature and energetics associated with these interactions were characterized using PIXEL and supported by ab initio quantum mechanical calculations using TURBOMOLE. In addition, the calculations performed on the evaluation of the electrostatic potential provide deeper insights into the nature of lp⋯π interactions. This journal is © The Royal Society of Chemistry.

Dey D.,Indian Institute of Science | Mohan T.P.,Rallis India Ltd. | Vishalakshi B.,Mangalore University | Chopra D.,Indian Institute of Science
Crystal Growth and Design | Year: 2014

A comprehensive analysis of the crystal packing and the energetic features of a series of four biologically active molecules belonging to the family of substituted 4-(benzylideneamino)-3-(4-fluoro-3-phenoxyphenyl)-1H-1,2,4-triazole-5-(4 H )-thione derivatives have been performed based on the molecular conformation and the supramolecular packing. This involves the formation of a short centrosymmetric R2 2(8) N-H⋯S supramolecular synthon in the solid state, including the presence of C-H⋯S, C-H⋯O, C-H⋯N, C-H⋯F, C-H⋯Cl, C-F⋯F-C, C-Cl⋯Cl-C, and C-H⋯π intermolecular interactions along with π-π stacking to evaluate the role of noncovalent interactions in the crystal. The presence of such synthons has a substantial contribution toward the interaction energy (-18 to -20 kcal/mol) as obtained from the PIXEL calculation, wherein the Coulombic and polarization contribution are more significant than the dispersion contribution. The geometrical characteristics of such synthons favor short distance, and the population of related molecules having these geometries is rare as has been obtained from the Cambridge Structural Database (CSD). Furthermore, their interaction energies have been compared with those present in our molecules in the solid state. The topological characteristics of the N-H⋯S supramolecular synthon, in addition to related weak interactions, C-H⋯N, C-H⋯Cl, C-F⋯F-C, and C-Cl⋯Cl-C, have been estimated using the quantum theory of atoms in molecules (QTAIM). In addition, an analysis of the Hirshfeld surface and associated fingerprint plots of these four molecules also have provided a platform for the evaluation of the contribution of different atom⋯atom contacts, which contribute toward the packing of the molecules in solids. (Figure Presented). © 2014 American Chemical Society.

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