Synthesis of ammonium [14C]thiocyanate

Ammonium [¹⁴C]thiocyanate was prepared from potassium [¹⁴C]cyanide with a radiochemical yield of 90%. [¹⁴C]hydrocyanic acid, generated from potassium [¹⁴C]cyanide by sulphuric acid, reacts with aqueous ammonia and elemental sulphur in the presence of trace amounts of ammonium sulphide to yield ammonium [¹⁴C]thiocyanate.     

Cavitation--a novel technique for making stable nano-suspensions

The purpose of the present study was to obtain nano-scale particles of styrene butadiene rubber. As SBR particles are elastic in nature, conventional methods of size reductions such as impacting, grinding are unable to achieve the final size. So, attempts have been made here to make the nano-particles of the SBR using cavitation technique. Both acoustic and hydrodynamic cavitation techniques have been employed and studied. Hydrodynamic cavitation has been proved to be more energy efficient than the acoustic cavitation on the basis of various parameters. The maximum production rate equivalent to 2 kg/h (solid processing) has been achieved in the newly developed hydrodynamic cavitation set-up (made in house). Similar to transient cavitation, stable cavitation has also been shown to contribute for reduction in the size of the material with very low variation in size. This technique has been proved successful for the size-reduction of the elastic material to nano-scale, thus it may also be used for the size-reduction of the other brittle and hard material by adjusting various cavitational parameters.     

Understanding guest and pressure‐induced porosity through structural transition in flexible interpenetrated MOF by Raman spectroscopy

Interpenetrating metal organic frameworks are interesting functional materials exhibiting exceptional framework properties. Uptake or exclusion of guest molecules can induce sliding in the framework making it porous or non‐porous. To understand this dynamic nature and how framework interaction changes during sliding, metal organic framework (MOF) 508 {Zn(BDC)( 4,4′‐Bipy)_0.5 · DMF(H₂O)_0.5} was selected for study. We have investigated structural transformation in MOF‐508 under variable conditions of temperature, pressure and gas loading using Raman spectroscopy and substantiated it with IR studies and density functional theory (DFT) calculations. Conformational changes in the organic linkers leading to the sliding of the framework result in changes in Raman spectra. These changes in the organic linkers are measured as a function of high pressure and low temperature, suggesting that the dynamism in MOF‐508 framework is driven by ligand conformation change and inter‐linker interactions. The presence of Raman signatures of adsorbed CO₂ and its librational mode at 149 cm⁻¹ suggests cooperative adsorption of CO₂ in the MOF‐508 framework, which is also confirmed from DFT calculations that give a binding energy of 34 kJ/mol. Copyright © 2015 John Wiley & Sons, Ltd.     

Maintenance of residual activity of Bt toxin by using natural and synthetic dyes: a novel approach for sustainable mosquito vector control

Mosquito control protein from Bacillus thuringiensis gets inactivated with exposure to sunlight. To address this issue, the potential of synthetic and natural dye was investigated as sunlight protectants. Bt SV2 in absence of dyes when exposed to sunlight showed reduced effectiveness against the fourth instars of mosquito larvae. Whereas acriflavin, congo red and violacein were able to maintain 86.4%, 91.6% and 82.2% mosquito larvicidal efficacy of Bt SV2 against IVth instars larvae of Anopheles stephensi Meigen after exposure to sunlight. Similarly, beetroot dye, acriflavin, congo red and violacein maintained 98.4%, 97.1%, 90.8% and 70.7% larvicidal activities against Aedes aegypti Linnaeus after sunlight exposure. Prodigiosin was found to be the best photo-protectant by simultaneously protecting and enhancing Bt activity by 6.16% and 22.16% against A. stephensi and A. aegypti, respectively. Combination of dyes with Bt formulations can be a good strategy for mosquito control programmes in tropical and sub-tropical regions.     

Interfacial Engineering of CdO–CdSe 3D Microarchitectures with in situ Photopolymerized PEDOT for an Enhanced Photovoltaic Performance

In the present work, porous 3D CdO‐microstructured electrode obtained by pyrolysis of 3D CdCO₃ microstructures is self‐sensitized with CdSe using an ion exchange reaction. After sensitization, an interfacial treatment of the CdO–CdSe interface is performed by depositing a thin film of PEDOT using a photoinduce polymerization route. The microstructured electrode before and after interfacial treatment is characterized using field‐emission scanning microscope, energy dispersive X‐ray analyzer, contact angle measurement, UV–Visible absorption spectrophotometer and X‐ray photoelectron spectrometer. After constructing a liquid junction solar cell with a Pt counter electrode, the photovoltaic performance and interfacial charge transfer kinetics across the CdO–CdSe interface before and after PEDOT treatment are investigated. The results exhibit an improved interfacial charge‐transfer resistance after the PEDOT treatment, which leads to enhance the short‐circuit current by 15.81% and the power conversion efficiency by 19.82%.     

Synthesis,Characterization, and Antibacterial Activity of Novel (1H‐Benzo[d]imidazole‐2‐yl)‐6‐(diethylamino)‐3H‐one‐xanthene,Phenoxazine, and Oxazine

A series of novel (1H‐benzo[d]imidazole‐2‐yl)‐6‐(diethylamino)‐3H‐one‐xanthene, phenoxazine, and oxazine derivatives have been synthesized from 2‐(2′,4′‐dihydroxyphenyl) benzimidazole intermediate. Synthesized compounds 8a , 8b , 8c , 8d are fluorescent in solution, photophysical properties of compounds were studied and results revealed that compounds absorb and emit in UV–visible region with good fluorescence quantum yield. Synthesized compounds are thermally stable up to 300°C. The antibacterial activities of the synthesized compounds were studied by the well‐diffusion method. Escherichia coli (ATTC‐25922), Staphylococcus aureus (ATCC‐25923), Micrococcus (ATCC‐4698), and Bacillus subtilis (ATCC‐55422) were used to investigate the antibacterial activities.     

Uncatalyzed synthesis of new substituted dihydro-2H-dipyrimido[1,2-a,4,5-d]pyrimidine-2,4(3H)-dione

Research on Chemical Intermediates - A convenient and new method has been developed for the synthesis of highly substituted dihydro-2H-dipyrimido[1,2-a,4,5-d]pyrimidine-2,4(3H)-dione derivatives by...