Isolation and characterization of biofumigant from leaves of Lantana camara for control of stored grain insect pests

Due to environmental concerns, health hazards to man and the evolution of resistance in insect pests, there have been constant efforts to discover newer insecticides both from natural sources and by chemical synthesis. Natural sources for novel molecules hold promise in view of their eco-friendly nature, selectivity and mammalian safety. We have isolated one natural bioactive molecule from the leaves of Lantana camara named Coumaran, based on various physical-chemical and spectroscopic techniques (IR, H-1 NMR, C-13 NMR and MS). Coumaran is highly toxic and very low concentration is needed for control of stored product insects. This molecule has potent grain protectant potential and caused significant reduction in F1 progeny of all the three species in the treated grain and the progeny was completely suppressed at 30 mu g/l. The differences in germination between the control and treated grains were not significant. The lack of any adverse effect of Coumaran on the seed germination is highly desirable for a grain protectant, becoming a potential source of biofumigant for economical and environmentally friendly pest control strategies against stored grain pests during storage of grains or pulses. (C) 2013 Elsevier B.V. All rights reserved.

Organic fragments from graphene oxide: Isolation, characterization and solvent effects

As-prepared graphene oxide (GO) contains oxidative debris which can be washed using basic solutions. We present the isolation and characterization of these debris. Dynamic light scattering (DLS) is used to monitor the separation of the debris in various solvents in the presence of different protic and aprotic alkylamino bases. The study reveals that the debris are rich in carbonyl functional groups and water is an essential component for separation and removal of the debris from GO under oxidative reaction conditions.

Isolation and characterization of a bioflocculant from Bacillus megaterium for turbidity and arsenic removal

A biodegradable flocculant was produced during growth of Bacillus megaterium. The major component of the bioflocculant was found to be a polysaccharide composed of some proteins. Fourier transform infrared (FTIR) spectra analysis revealed the presence of carboxyl and hydroxyl groups in the bioflocculant, and thermal characterization by differential scanning calorimetly (DSC) showed the transition and crystalline melting point at 90-105 degrees C. The effects of bioflocculant dosage and pH on the flocculation of mineral suspensions were evaluated. The bioflocculant exhibited good flocculating capability on mineral suspensions and achieved flocculating efficiencies of 90 percent for k-aolinite and 85 percent for hematite suspensions at a dosage of only 5 mL/L. The maximum arsenite removal was found to be 90 percent at a bioflocculant dosage of 2 g/L, which is better than traditional chemicalflocculants. This study demonstrates that microbial bioflocculants have potential for application in environmental cleanup, such as in the flocculation of mineral fines and in the remediation of solutions that contain toxic heavy metals.

Non-covalent C-Cl center dot center dot center dot pi interaction in acetylene-carbon tetrachloride adducts: Matrix isolation infrared and ab initio computational studies

Non-covalent halogen-bonding interactions between n cloud of acetylene (C2H2) and chlorine atom of carbon tetrachloride (CCl4) have been investigated using matrix isolation infrared spectroscopy and quantum chemical computations. The structure and the energies of the 1:1 C2H2-CCl4 adducts were computed at the B3LYP, MP2 and M05-2X levels of theory using 6-311++G(d,p) basis set. The computations indicated two minima for the 1:1 C2H2-CCl4 adducts; with the C-Cl center dot center dot center dot pi adduct being the global minimum, where pi cloud of C2H2 is the electron donor. The second minimum corresponded to a C-H...Cl adduct, in which C2H2 is the proton donor. The interaction energies for the adducts A and B were found to be nearly identical. Experimentally, both C-Cl center dot center dot center dot pi and C-H center dot center dot center dot Cl adducts were generated in Ar and N2 matrixes and characterized using infrared spectroscopy. This is the first report on halogen bonded adduct, stabilized through C-Cl center dot center dot center dot pi interaction being identified at low temperatures using matrix isolation infrared spectroscopy. Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) analyses were performed to support the experimental results. The structures of 2:1 ((C2H2)(2)-CCl4) and 1:2 (C2H2-(CCl4)(2)) multimers and their identification in the low temperature matrixes were also discussed. (C) 2015 Elsevier B.V. All rights reserved.