Copper(II) complexes of acid amide derivatives of 2-aminopyridineand an exogenous ligand

The bidentate ligands, 2-[(N-acetyl)aminopyridine] (AAPH, A) and 2-[(N-benzoyl)aminopyridine] (BAPH, B) have been used to synthesize copper(II) complexes including an exogenous ligand X (X = AcO^–, HCO₂ ^–, N₃ ^– and benzimidazole). The complexes were characterized by elemental analysis, electronic and vibrational spectroscopy, magnetic and e.s.r. studies. E.s.r. parameters and visible spectra indicated that all the complexes are monomers and exist in distorted octahedral geometry except for benzimidazole. With benzimidazole as an exogenous ligand, a five coordinate complex is formed.     

Imperviousness of the hydrophobic silica aerogels against various solvents and acids

The experimental results on the imperviousness of the silica aerogels against various organic solvents and acids, are reported. Various types of hydrophobic silica aerogels were prepared using methyltrimethoxysilane (MTMS); tetraethoxysilane (TEOS) with ethyltriethoxysilane (ETES) and phenyltriethoxysilane (PTES) as co-precursors. The organic solvents used were: methanol, ethanol and acetone, and the acids used were: hydrochloric acid (HCl), nitric acid (HNO₃) and sulphuric acid (H₂SO₄). The imperviousness of the aerogels against these solvents and acids were tested with the variation of the percentage of organic solvents and acids in water from 10 to 100% and was characterized by the contact angle measurements. It was observed that in all the cases, the contact angle decreased with an increase in the percentage of solvent in water. While there was no absorption of the solvent up to 20% in water by the ETES and PTES modified aerogels, the MTMS-based aerogels showed the imperviousness up to 60% of the solvent in water. The MTMS aerogels were also impervious against all the three acids up to 100%, while the ETES and PTES modified aerogels could withstand only up to 80% of acids in water.     

Heat capacity and vibrational dynamics of polyvinylidene fluoride (β-form)

Polyvinylidene fluoride (PVDF) is a polymer of industrial importance, mainly due to its piezoelectric and pyroelectric properties. A comprehensive study of the normal modes and their dispersion in PVDF (β-form) has been reported in the reduced zone scheme using Wilson’s GF matrix method as modified by Higgs. A Urey-Bradley force field has been used. The evaluation of normal modes and their dispersion has been taken to logical conclusion by calculating the heat capacity as a function of temperature. The extent of agreement with the experimental data supports the potential field. Characteristic features of the dispersion curves such as repulsion and exchange of character have also been discussed.     

Simultaneous determination of Cs and Sr in the high level waste by ion-chromatography

A method based on ion-chromatography has been developed for determination of Cs and Sr in high level waste (HLW) without matrix separation. The acidity of HLW (3 M HNO₃) was decreased to 0.01 M by addition of NaOH. Chromatographic separation of Cs⁺ and Sr⁺⁺ in presence of bulk Na⁺ has achieved using methane sulphonic acid as mobile phase in isocratic and gradient mode. The calibration plot was linear for the concentration range of 0.5–12 mg/L for Cs and 0.025–6 mg/L for Sr with regression coefficients close to 1. RSD obtained for Cs and Sr was 1 and 5 % respectively. Detection limit calculated as 3(S/N) was found to be 20 μg/L for Cs and 30 μg/L for Sr. The standard addition procedure was used to validate the developed method. The samples received from PREFRE, Tarapur and WIP, BARC were analyzed by the new method and the results are presented.     

Remediation of Textile Dye Waste Water Using a White-Rot Fungus Bjerkandera adusta Through Solid-state Fermentation (SSF)

A strict screening strategy for microorganism selection was followed employing a number of white-rot fungi for the bioremediation of textile effluent, which was generated from one Ireland-based American textile industry. Finally, one fungus Bjerkandera adusta has been investigated in depth for its ability to simultaneously degrade and enrich the nutritional quality of highly coloured textile effluent-adsorbed barley husks through solid-state fermentation (SSF). Certain important parameters such as media requirements, moisture content, protein/biomass production and enzyme activities were examined in detail. A previously optimised method of dye desorption was employed to measure the extent of dye remediation through effluent decolorisation achieved as a result of fungal activity in SSF. B. adusta was capable of decolourising a considerable concentration of the synthetic dye effluent (up to 53%) with a moisture content of 80-85%. Protein enrichment of the fermented mass was achieved to the extent of 229 g/kg dry weight initial substrate used. Lignin peroxidase and laccase were found to be the two main enzymes produced during SSF of the dye-adsorbed lignocellulosic waste residue.     

Effects of block size of pluronic polymers on the water structure in the corona region and its effect on the electron transfer reactions

Effects of constituent block size of triblock copolymers on the nature of the water molecules in the corona region of their micelles have been investigated using time-resolved fluorescence measurements. The physical nature of the water molecules in the micellar corona region of the block copolymer, Pluronic F88 ([ethylene oxide (EO)]103-[propylene oxide (PO)]39-EO103), has been studied using a solubilized coumarin dye. Solvent reorientation time and rotational correlation time have been measured and compared with another block copolymer, Pluronic P123 (EO20-PO70-EO20), which has a different composition of the constituent PO and EO blocks. It is noted that due to the presence of larger number of EO blocks in F88 as compared with P123, the corona region of the former micelle is more hydrated than that of the latter. The solvent reorientation time and rotational correlation time are found to be relatively shorter for F88 as compared with P123. This indicates that the water molecules in the corona of the F88 micelle are more labile than those of P123, which is also supported from the estimated number of water molecules associated with each EO unit, measured from the size of each type of micelle and its aggregation number. To understand the effect of block size on the chemical reactions in these microheterogeneous media, electron transfer reactions have been carried out between different coumarin acceptors and N, N-dimethylaniline donor. The electron transfer results obtained in F88 micelles have been compared with those obtained in P123, and the results are rationalized on the basis of the relative hydration of the two triblock copolymer micelles.     

One Pot Regioselective Synthesis and Antimicrobial Studies of Some Novel Indazolyl–Thiazole Derivatives

2‐Benzylidene‐1‐tetralones, obtained via Claisen condensation of 1‐tetralones with aromatic aldehydes, in one pot condensation with thiosemicarbazide/semicarbazide and α‐haloketones in the presence of trifluoroethanol and conc. HCl gives rise to a series of new substituted‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazol‐2yl‐thiazoles. The condensation was also carried out in two steps, and the intermediates 3‐substituted‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazole‐2‐carbothioamides/carboxamides, obtained in the first step by the reaction of 2‐bezylidene‐1‐tetralones with thiosemicarbazide/semicarbazide, on reaction with α‐haloketones gives rise to indazolyl–thiazoles. A detailed X‐ray diffractometry of intermediate (3aR)‐3‐phenyl‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazole‐2‐carbothioamide were carried out to establish its crystal structure. Further, density functional theory studies on (3aR)‐3‐phenyl‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazole‐2‐carbothioamide and its regioisomer were carried out. There is good correlation between the theoretical and experimental spectral data. The antibacterial and antifungal activities of the selected compounds were examined, and some are found to exhibit excellent activities.     

Willgerodt–Kindler reaction-driven one pot solventless entry to 2-oxazolines

We report an efficient and green protocol for the synthesis of 2-oxazolines by the reaction of aromatic nitriles with β-aminoalcohols using sulfur under solvent-free conditions. The reaction occurs via the Willgerodt–Kindler mechanism followed by transamidation and dehydrosulfuration. This methodology offers several advantages such as good yields, mild and practical reaction conditions, simple work-up procedure, and broad substrate scope, which makes the process simple, convenient, and environmental-friendly.