Two organic phosphors 5,5'-(4-pyridinylmethylene)bis[1,3-dimethyl-2,4,6-(1 H,3 H,5 H)-pyrimidinetrione] (BP) and 5,5'-(4-nitrophenylmethylene)bis[1,3-dimethyl-2,4,6-(1 H,3 H,5 H)-pyrimidinetrione] (BP-NO 2) have been synthesized through a one pot reaction of N, N-dimethylbarbituric acid and pyridine aldehyde in acetonitrile at 80 degC. The synthesized phosphors were characterized by single-crystal X-ray crystallography, Fourier transform infrared spectroscopy, UV-vis spectroscopy, thermogravimetry analysis and photoluminescence (PL) spectroscopy. A broadband PL emission spectrum ranging from 400 to 800 nm was recorded from both phosphors. The BP showed a luminescence peak at ca. 560 nm (2.21 eV), while the BP-NO 2 exhibited a peak at 590 nm (2.1 eV), which reflect pure yellow emissions. The optimized geometry of the phosphors has been studied with a quantum chemical approach using the density functional theory. The highest occupied and lowest unoccupied molecular orbitals are predicted from the calculations. [All rights reserved Elsevier].

A fluorescent turn-on sensor for the selective and sensitive detection of sulfur mustard simulants in water that uses a metal-ion indicator displacement assay (IDA) has been devised. In this IDA approach, a sulfur mustard simulant (the analyte) is allowed to react with a dithiol (1) to form a podand (2). This podand has a strong affinity to bind with Cd2+ and displaces an indicator (4-methylesculetin, ME) from a Cd2+ indicator complex (8) to give a turn-on of fluorescence. The detection is rapid and highly selective, as we did not observe any interference from other electrophiles, even from the oxygen analogue of the mustard simulant. The protocol was successfully used for the detection of the simulant present on surfaces and in soil samples.

Modern solar energy harnessing technology demands high grade energy to achieve efficient power generation with compact plant size and least payback period. But readily available solar energy is low grade energy. Concentrated Solar Power (CSP) technology is capable to cater the demand. Reflector or mirror in CSP contributes 50% of total cost of installation, hence huge initial investment and high life cycle costs are the major challenges associated with such plants. Moreover due to adverse service conditions and environmental impacts, it gets degraded early, causing substantial drop in efficiency and consequently reduction in life cycle. Fresnel lens as solar concentrator in Photovoltaic/Thermal (PV/T) applications may prove to be a promising alternative due to its potential to overcome technocommercial constraints associated with conventional reflector based CSP. A critical review covering global CSP deployment, operational requirement and failure mechanism in mirrors/reflectors is being presented. As an alternative, design considerations of Fresnel lens and its effect on various efficiencies, reflectance, transmittance and associated losses are discussed. Learning from early research work, innovative and emerging trends, economics, challenges and advantages are also presented. (C) 2014 Elsevier Ltd. All rights reserved.