Tetraamminecopper(2+) bis(permanganate) ([Cu(NH3)4](MnO4)2; 1 ) was prepared, and its properties were studied in both aqueous solution and the solid phase. The presence of H‐bond interactions between the ammonia ligand of the complex cation and an O‐atom of the permanganate ion was detected by IR and Raman methods. The solid‐phase thermal deammoniation of 1 led to an unusual intramolecular redox reaction between the Mn O⋅⋅⋅H N linkage with formation of NH4NO3 and CuMn2O4‐type mixed oxides instead of stepwise deammoniation, even below 100°. The thermal deammoniation of 1 in aqueous solution led, instead of to hydrated copper(2+) bis(permanganate), to the formation of NH4MnO4 ( 2 ). Since the temperature of the thermal deammoniation of 1 is lower than the decomposition temperature of the permanganate ion, the regulated solid‐phase decomposition of 1 allowed preparation of CuMn2O4‐type oxides with mixing of copper and manganese at the atomic level. 相似文献
Polymer-in-salt-electrolytes (PISEs) are an important class of electrolytes as they carry the promise of faster and single ion transport. Unfortunately, due to unavailability of a suitable polymer host PISE has still not reached to commercial level. In the present work, using a novel synthesis protocol developed by the group, glutaraldehyde crosslinked wheat starch has been successfully modified with sodium iodide (NaI) to synthesize a flexible PISE membrane with desired electrochemical properties. Present paper reports the effect of crosslinker and exposure to high humidity ambience on electrochemical and morphological properties. It has been established that on exposure to higher humidity atmosphere starch-based PISEs stabilize at lower resistance value, but with higher ion relaxation time, which indicates that effect of high humidity treatment is more on salt dissociation instead of assisting the ion transport. The studied materials have conductivity ≈0.01 S cm−1 range with ESW >2.5 V, ensuring its usability in electrochemical devices. The developed synthesis protocol does not require any complicated synthesis route and/or sophisticated instrument hence the overall process is economical also, adding up to its potentiality for energy device fabrication. 相似文献
Zn1 − xFexS (x=0.0, 0.1, 0.2, 0.4 and 0.6) nanocrystals have been obtained by chemical co-precipitation from homogeneous solutions of zinc and iron salt compounds, with S2− as precipitating anion formed by decomposition of thiophenol. The TEM micrographs show a spherical shape for ZnS nanocrystals and their average size is around 7 nm. The optical absorption spectra indicate a blue shift of the absorption edge with increasing Fe-content. The luminescence of nanoparticles excite at about 370 nm with an emission peak at around 490 nm. At room temperature, ESR signal characteristic of Fe3+ was observed in samples of all concentrations. 相似文献
Complementing classical isocratic elution, several more sophisticated operating modes have been proposed and are applied in preparative chromatography in order to improve performance. One such approach is gradient elution, where the solvent strength is altered by varying the fraction of a modifier added to the mobile phase to enhance selectivity and to achieve faster elution. Another useful technique is closed-loop recycling, allowing better peak resolution and increased yields. This study focuses on a modified new scheme which incorporates the advantages of both gradient elution and closed-loop recycling for the separation of a ternary mixture where the intermediately eluting component is the target. A parametric study was carried out using typical adsorption isotherm parameters to elucidate the effects of varying loading factors and parameters specific to the two basic operational modes on production rates and yields. A comparison was also made between the proposed scheme and conventional techniques. It was found that the studied scheme could exploit increased column loadings and offers significantly higher production rates. 相似文献
Aqueous colloidal manganese dioxide (MnO2) was prepared via titration by using potassium permanganate and sodium thiosulphate in aqueous neutral medium. The kinetics of oxidation of d-glucose onto the surface of colloidal MnO2 have been studied spectrophotometrically. The results show that the rate of initial stage (nonautocatalytic path) increases with increasing the [d-glucose], [H+], and temperature and also upon addition of nonionic surfactant Triton X-100 (TX-100), which indicates that the surfactant enhances the concentration of d-glucose at the surface of the colloidal MnO2. Hydrogen bonding interaction seemingly arises between –OH groups of d-glucose and oxygen of the ether linkages of polyoxyethylene chain of TX-100. A possible mechanism of the oxidative degradation of d-glucose is discussed in terms of d-glucose/TX-100 and colloidal MnO2 interaction. 相似文献
A large number of α-naphthyl selenium and tellurium compounds (1-14) have been prepared through two different methods. The first method involves the alkylation of sodium 1-naphthylselenolate/tellurolate, generated in situ using hydrazine hydrate as reducing agent while the second method involves the reaction of in situ generated α-naphthylseleno/telluromagnesium bromide with an appropriate electrophile. The synthesized alkyl-1-naphthyl selenides/tellurides and some α,ω-bis(1-naphthylseleno)alkanes have been characterized with the help of elemental analysis and using various spectroscopic techniques viz., NMR (1H, 13C, 77Se and 125Te), IR, UV/vis spectroscopy and mass spectrometry (only in few representative cases). Interpretation of 1H, 13C NMR spectra and assignment of individual resonances for tris(1-naphthylseleno)methane have been done with the help of [1H-1H] and [1H-13C] correlation spectroscopy (COSY). X-ray crystallographic results and molecular geometry of benzyl-1-naphthyl selenide, 2 and diphenylmethyl-1-naphthyl selenide, 3 have also been illustrated. 相似文献
This paper reviews the practical applications of solid phase microextraction-High performance liquid chromatography in the analysis of toxic metal species as these are important contaminants and are carcinogenic. Their determination in formulations, in feed and food, and in complex environmental matrices (e.g., waste water and industrial effluents) often requires analytical methods capable of high efficiency, unique selectivity, and high sensitivity. Solid phase microextraction (SPME) requires low solvent consumption and is quick in use. SPME is used for extraction and online desorption of analytes with the mobile phase of HPLC and subsequent detection by UV, ICP-MS or ESI-MS as detectors. Different SPME-HPLC methods are summarized in this article to demonstrate the usefulness of this technique for metallic species of As, Cr, Pb, Hg and Se. 相似文献
Polymer electrolyte has seen tremendous growth after works of Fenton & Armand, and energy devices are being produced at commercial level. Today’s social lifestyle needs miniaturized energy devices at every step of life; consequently, they add up to chemical garbage of the world. The sustainable development in the field needs eco-friendly energy devices. Hence, starch (being at low cost, abundant in nature and eco-friendly) has received great scientific attention. In recent past, many attempts have been made to modify the various starches to get fast ion-conducting materials. In our laboratory, also, wheat, potato, rice and arrowroot starches have been modified with different sodium salts, and in each case, considerably high-conducting (>10−3 S/cm) films have been found. In present case, also, a high-conducting transparent film (10−2 S/cm) is obtained with corn starch and NaClO4 salt after being crosslinked with glutaraldehyde (GA). Bode plots (both phase and magnitude), capacitive-response plot, capacitive-frequency plots and linear sweep voltammetry curves are analysed to explain the possibility of using the prepared electrolyte in capacitive device. The larger electrochemical stability window (ESW) ~ 2.4 V and smaller ion relaxation time ~ 65 μs make it a potential candidate for device fabrication. The equivalent series resistance is ~6.252 Ω for 0.8-mm-thick sample.
α‐amino nitrones are found to have a great significance in the synthesis of peptides. Simple reaction methodology, high yield, and atom efficiency in these reactions have made this protocol highly attractive. The synthetic route may be extended to the synthesis of dipeptides in enantiomerically pure form. Potential biological activity of the newly synthesized peptides is the major application in this new methodology. 相似文献