Visible-light-promoted oxidative coupling of styrene with cyclic ethers

A new visible-light-promoted oxidative coupling of vinylarenes with cyclic ethers has been developed using rose bengal as photocatalyst and tert-butyl hydrogenperoxide(TBHP) as oxidant under ambient air at room temperature. A library of α-oxyalkylated ketones with broad functionalities has been synthesized in moderate to good yields. A radical mechanism is suggested for the present protocol.     

Relative efficacy of water use in five varieties of Abelmoschus esculentus (L.) Moench. under water-limited conditions

In the present investigation, five varieties of okra (Abelmoschus esculentus (L.) Moench.) were screened for their water use efficiency under two water regimes, viz., 60% and 100% filed capacity. Drought stress was imposed at 60% field capacity from 30 to 70 days after sowing, while the control pots were maintained at 100% field capacity throughout the period of entire growth. Biomass and yield, leaf area duration, cumulative water transpired water use efficiency, net assimilation rate, mean transpiration rate and harvest index under water deficit level were measured. Water use efficiency significantly increases in all the okra varieties under water-limited environment. Drought stress decreased the biomass and yield, leaf area duration, cumulative water transpired, net assimilation rate, mean transpiration rate and harvest index in the okra varieties studied. But among the varieties, variety JK Haritha showed better results. None of the varieties studied had showed increased drought tolerance than the control.     

Mineral uptake and biochemical changes in Helianthus annuus under treatment with different sodium salts

Experiments were conducted to study the effects of different sodium salts viz., sodium chloride (NaCl), sodium sulphate (Na(2)SO(4)) and sodium carbonate (Na(2)CO(3)) on growth, dry matter production, mineral contents, biochemical constituent and enzyme activities of sunflower (Helianthus annuus L.). The germinating sunflower seeds were treated with 10, 20 and 50mM NaCl and Na(2)SO(4) and 5, 10 and 15 mM Na(2)CO(3). The seedling growth, minerals, chlorophyll content and biochemicals like protein and free amino acid contents with enzyme activities like ATPase and protease were analysed on 8 DAS. The seedlings were separated into root, stem, leaf and cotyledon on 8 DAS. All the treatments decreased the germination percentage; shoot length, root length, leaf area and dry weight, chlorophyll and protein contents significantly. Potassium, sodium and free amino acid contents; activities of ATPase and protease were increased when compared to control. This effect was very high in the Na(2)CO(3) treated seedlings this was followed by Na(2)SO(4) and NaCl treated seedlings. From the results of this investigation, it is clear that, the sunflower seedlings were affected significantly in the Na(2)CO(3) treatments, and followed by Na(2)SO(4) and NaCl treatments.     

Simple Chemical Route Synthesis of Fe2O3 Nanoparticles and its Application for Adsorptive Removal of Congo Red from Aqueous Media: Artificial Neural Network Modeling

Nanocrystalline Fe₂O₃ powder was synthesized by a simple chemical route involving FeCl₃ and NaOH. The Fe₂O₃ powder thus prepared was characterized using x-ray diffraction study, scanning electron microscopy, and Fourier transform infrared spectroscopy. The adsorption properties of crystalline Fe₂O₃ powder have been investigated with an aim to explore a possible low cost and efficient way to remove Congo red (CR) from waste water. Fe₂O₃ powder was found as an excellent adsorbent for CR from aqueous medium. Adsorption capacity as much as 203.66 mg g^?1 is reported at room temperature. Effect of different experimental parameters such as reaction pH, initial CR dye concentration, adsorbent dose, and reaction temperature were studied on adsorption capacity of Fe₂O₃ powder and modeled by artificial neural network (ANN). Optimal ANN structure (4–5–1) shows minimum mean squared error (MSE) of 0.00235 and determination coefficient (R²) of 0.991 with Levenberg–Marquardt algorithm. Isotherm analysis of experimental data exhibited better fit to the Langmuir isotherm. The adsorption process was found to follow second-order kinetics as depicted by the analysis of experimental results. Thermodynamic study shows that the adsorption process is endothermic, spontaneous, and thermodynamically favorable in the temperature range of 27°C to 60°C.     

Engaging Allene‐Derived Zwitterions in an Unprecedented Mode of Asymmetric [3+2]‐Annulation Reaction

Catalytic addition of chiral phosphine, that is, (R)‐ or (S)‐SITCP, to an α‐substituted allene ester generated a zwitterionic dipole. Under optimized reaction conditions, this dipole could engage isatine‐derived N‐Boc‐ketimines in a novel mode of [3+2] annulation reaction. Pyrrolinyl spirooxindoles are thus afforded in high yields and with excellent enantioselectivities. The unprecedented annulation reaction successfully facilitated the construction of sp³‐rich and highly substituted 3,2′‐pyrrolidinyl spirooxindoles supporting many chiral centers.     

Organoruthenium derivative of the cyclic [H7P8W48O184]33- anion: [{K(H2O)}3{Ru(p-cymene)(H2O)}4P8W49O186(H2O)2]27-

Reaction of [Ru(p-cymene)Cl2]2 with [H7P8W48O184]33- (P8W48) in aqueous acidic medium results in the organometallic derivative [{K(H2O)}3{Ru(p-cymene)(H2O)}4P8W49O186(H2O)2]27- (1); in addition to the four {Ru(p-cymene)(H2O)} units, an unusual WO6 group with four equatorial, terminal ligands is also grafted to the crown-shaped P8W48 precursor.