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81.
Jasmin Shah M. Rasul Jan Behisht Ara 《International journal of environmental analytical chemistry》2013,93(15):1077-1085
A simple sensitive spectrophotometric method has been developed for the determination of atrazine in herbicide formulations and real samples. The method was based on the reaction of atrazine with pyridine to form a quaternary halide which in the presence of alkali forms a carbinol base. The heterocyclic ring of the carbinol base breaks and forms the glutaconic dialdehyde. The glutaconic dialdehyde group was coupled with sulfanilic acid to form a yellow coloured product having λ max 450 nm or coupled with aniline to form a orange red coloured product having λ max 480 nm. The Beer's law was obeyed over the range from 0.1 to 25 µg mL?1 and molar absorptivity 1.5 × 104 L mol?1 cm?1 for sulfanilic acid, and from 0.08 to 12 µg mL?1 and molar absorptivity 1.3 × 104 L mol?1 cm?1 for aniline were observed. The reaction conditions and other analytical parameters were optimised. The proposed method has been successfully applied for the analysis of commercial formulations and real samples. 相似文献
82.
Kishor R. Shah Royston H. Filby Albert I. Davis 《International journal of environmental analytical chemistry》2013,93(1):63-73
Thermal neutron activation analysis, a high-resolution Ge(Li) gamma-ray spectrometer, and an IBM 360/67 digital computer were used to determine the concentration of Na, K, Sc, Cr, Mn, Fe, Co, Cu, Zn, Se, Br, Rb, Sb, Cs, and Hg in ground coffee and tea. This nondestructive multielement technique requires neither pre- nor postirradiation chemistry and eliminates problems of reagent contamination. The method is simple, precise and sensitive to 15 elements. Interferences from fast neutron (n, p) and (n, α) reactions are small and, if necessary, corrections may be applied easily. This technique can be applied to percolated tea and coffee. 相似文献
83.
C. A. Snyder N. C. Tice J. B. Maddox J. O. E. Young M. G. Mazzotta B. D. Garabato J. W. Evans L. A. Dopierala S. A. Shah Z. A. Claytor A. C. Smith 《Transition Metal Chemistry》2013,38(8):801-809
A series of 5,6-fused ring cyclopentadienyl tricarbonyl manganese and rhenium complexes, [M(CO)3{η 5-1,2-C5H3(1,4-(R)2N2C2}] (2a–3d) were isolated by employing an off-metal ring closure route. Reacting thallium cyclopentadienide (Cp) salts (1a–d) with [MBr(CO)5] (M = Mn, Re) provided pyridazyl complexes (2a–3d) in high yield (75–99 %). Spectroscopic characterization (NMR, IR, MS) confirmed the identity of the desired organometallic pyridazines. The off-metal synthetic pathway employed did improve upon the isolation of these complexes as compared to previously reported routes. The molecular and electronic structure of complexes 2a–3d and their optimal energy structures have been characterized with quantum chemistry calculations. Vibrational frequencies calculated were compared to their experimental counterparts. The excited state calculations predict that the dominant low-energy transition involves a ligand-to-metal charge transfer. 相似文献
84.
Ramesh H. Shah 《Journal of carbohydrate chemistry》2013,32(1):139-146
D-Erythrose was synthesized in four steps from D-ribono-1,4-lactone via the 3,5-O-benzylidene derivative of the latter compound. Reduction of the benzylidene D-ribonolactone, and periodate cleavage of the resulting 3,5-O-benzylidene-D- ribitol were performed in a one-flask reaction. The ensuing 2,4-O-benzylidene-D-erythrose was hydrolyzed with 10% acetic acid to obtain syrupy D-erythrose. 相似文献
85.
The first report of natural l-vasicine as tridentate chiral ligand for the enantioselective addition of diethylzinc to a variety of aliphatic and aromatic aldehydes is described. The ligand generates R-isomer of the secondary alcohols upto 98% ee. The quinazoline structure possibly imparts rigidity to the ligand and hence, consistently high enantioselectivity. The importance of the quinazoline ring was also supported by the reaction with other related ligands, partially lacking the structural features, thus resulting in poor enantioselectivity. 相似文献
86.
N-Sulfonyl imines have been synthesized in good to excellent yields from aldehydes and chloramine-T using proline as an organocatalyst in aqueous medium at ambient temperature. The protocol is applicable to a wide range of aldehydes, especially enals exhibit remarkable efficiency in the reaction. The reaction presumably occurs via iminium activation and opens new avenues for the synthesis of N-sulfonyl imines under environmentally benign and mild conditions. 相似文献
87.
Zia‐ur‐ Rehman Muhammad Moazzam Naseer Afzal Shah Saqib Ali Auke Meetsma 《Heteroatom Chemistry》2015,26(2):123-133
A fascinating ligand, 4‐formylpiperazinium 4‐formylpiperazine‐1‐carbodithioate (L‐salt) has been reacted with two electronically and sterically different trimethyltin(IV) chloride and triphenyltin(IV) chloride. The complexes 1 and 2 were characterized by elemental analysis, spectroscopic techniques, and X‐ray single crystal analysis. The latter technique confirmed the polymeric and monomeric nature of 1 and 2 , respectively. Both 1 and 2 showed intriguing molecular packing properties in the solid state. However, the packing of 1 is more interesting and unique where one‐dimensional polymer chains self assemble in two‐over‐two saltire‐shaped fashion to provide an overall multilayered structure. The different behavior of L toward two different tin(IV) compounds can be attributed to different electronic and steric environments around metal center. 相似文献
88.
Ejaz Mohsin Azad Muhammad Muzammil Shah Atta ur Rehman Afaq S. Kamran Song Jung-il 《Cellulose (London, England)》2022,29(3):1775-1790
Cellulose - This study focuses on the synergistic effects of hydroxide based nanoparticles namely aluminum trihydrate (ATH) and zirconium hydroxide (ZHO) on the mechanical characteristics, thermal... 相似文献
89.
A new high: Cannabis as a budding source of carbon-based materials for electrochemical power sources
Zahra I. Rana Ami R. Shah Alice V. Llewellyn Katrina Mazloomian Patricia McAlernon Thomas S. Miller Patrick L. Cullen Paul R. Shearing Dan J.L. Brett 《Current Opinion in Electrochemistry》2022
Cannabis sativa L., a low-cost, fast-growing herbaceous plant, is seeing a resurgence in widespread cultivation as a result of new policies and product drive. Its biodegradable and environmentally benign nature coupled with its high specific surface area and three-dimensional hierarchal structure makes it an excellent candidate for use as a biomass-derived carbon material for electrochemical power sources. It is proposed that this ‘wonder crop’ could have an important role in the energy transition by providing high-functioning carbon-based materials for electrochemistry. In this article, all instances of C. sativa usage in batteries, fuel cells and supercapacitors are discussed with a focus on highlighting the high capacity, rate capability, capacitance, current density and half-wave potential that can be achieved with its utilisation in the field. 相似文献
90.
Sodiq Adeyeye Nafiu Syed Shaheen Shah Dr. Abdul Aziz Dr. M. Nasiruzzaman Shaikh 《化学:亚洲杂志》2021,16(14):1956-1966
Direct attachment of gold nanoparticles to a green support without the use of an external reducing agent and using it for removing toxic pollutants from wastewater, i. e., reduction of nitroarene to amine, are described. A novel approach involving the reduction of gold by the jute plant (Corchorus genus) stem-based (JPS) support itself to form nanoparticles (AuNPs) to be used as a catalytic system (‘dip-catalyst’) and its catalytic activity for the hydrogenation of series of nitroarenes in aqueous media are presented. AuNPs/JPS catalyst was characterized using SEM, UV-Vis, FTIR, TEM, XPS, and ICP-OES. Confined area elemental mapping exhibits uniform and homogeneous distribution of AuNPs on the support surface. TEM shows multi-faceted AuNPs in the range of 20–30 nm. The reactivity of AuNPs/JPS for the transfer hydrogenation of nitroarene as well as hydrogenation of quinoline under molecular H2 pressure was evaluated. Sodium borohydride, when used as the hydrogen source, demonstrates a high catalytic efficiency in the transfer hydrogenation reduction of 4-nitrophenol (4-NP). Quinoline is quantitatively and chemoselectively hydrogenated to 1,2,3,4-tetrahydroquinoline (py-THQ) using molecular hydrogen. Reusability studies show that AuNPs are stable on the support surface and their selectivity is not affected. 相似文献