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1.
A mild and efficient protocol for the coupling of indoles and pyrroles with allyl halides such as allyl bromide, crotyl bromide and propargyl bromide in the presence of gallium metal in a Bu4NBr-DMF-H2O system has been developed. The reaction is equally effective when cadmium is used in lieu of gallium and the corresponding 3-allyl indoles and 3-allyl pyrroles were obtained in almost comparable yields. 相似文献
2.
Mixed valent Pd(0)/Pd(II) nano‐sized aggregates supported onto a chemically robust layered zirconium carboxyphosphonate framework is prepared and its catalytic activity in Suzuki‐Miyaura cross coupling reaction is explored. The exceptionally high catalytic efficacy of the heterogeneous catalyst in Suzuki‐Miyaura cross coupling reaction is signified by remarkably short reaction time 2 minutes and high turnover frequency of 1.3 x 104 hr?1. The catalyst can be recycled several times without significant loss of catalytic efficacy, while spectroscopic, structural and microscopic investigations suggest the integrity of the catalyst even after fifth catalytic cycle. The unique ability of the zirconium carboxyphosphonate framework to interact strongly with palladium in dual Pd(0)/Pd(II) oxidation states has been attributed to this remarkable augmentation of catalytic efficacy. 相似文献
3.
4.
Gogoi Deepshikha Hussain Amreen A. Pal Arup R. 《Plasma Chemistry and Plasma Processing》2019,39(1):277-292
Plasma Chemistry and Plasma Processing - We report plasma based fabrication of an optoelectronic device with plasmon enhanced infrared sensitivity realized by integrating plasmonic gold... 相似文献
5.
A mild, efficient, and solvent‐free protocol for tetrahydropyranylation of alcohols in the presence of a catalytic amount of SnCl2 · 2H2O is reported. Simple filtration of the reaction mixture through a short silica‐gel pad gives the pure products in excellent yields. Depyranylation can also be achieved by adding methanol under similar reaction conditions. 相似文献
6.
Surfactant (SDS)‐mediated cleavage of imines was achieved with acetic anhydride to the corresponding carbonyls (aldehydes and ketones) and acetanilides in water at 25–30°C with very good to excellent yields, thus contributing significantly to the green chemistry concept. 相似文献
7.
Relaxation dynamics of plasmons in Au−SiO2 core-shell nanoparticles have been followed by femtosecond pump-probe technique. The effect of excitation pump energy and surrounding medium on the time constants associated with the hot electron relaxation has been elucidated. A gradual increase in the electron-phonon relaxation time with pump energy is observed and can be attributed to the higher perturbation of the electron distribution in AuNPs at higher pump energy. Variation in time constants for the electron-phonon relaxation in different solvents is rationalized on the basis of their thermal conductivities, which govern the rate of dissipation of heat of photoexcited electrons in the nanoparticles. On the other hand, phonon-phonon relaxation is found to be much less effective than electron-phonon relaxation for the dissipation of energy of the excited electron and the time constants associated with it remain unaffected by thermal conductivity of the solvent. 相似文献
8.
Mixed ionic and electronic conductivity of three solid charge transfer (CT) complexes of pyridine, 4-methylpyridine (γ-picoline) and 3,5-dimethylpyridine (3,5-lutidine) with ICl (iodine monochloride) are reported. Electrical parameters of the prepared complexes in the pellet form are evaluated at various temperatures and at wide frequency range by employing AC complex impedance spectroscopic technique. Suitable equivalent circuits for the Nyquist plots, which provide the most realistic model of the electrical properties of the CT complexes, have been suggested. Both transport number measurements and impedance spectra reveal that the conduction in γ-picoline-ICl complex is mainly due to ions, in 3,5-dimethylpyridine-ICl complex, it is due to both ions and electrons and in pyridine-ICl complex, it is predominantly due to electrons. The a.c. conductivity measurements of the CT complexes have been carried out in the frequency range of 10–105 Hz within the temperature range of 303–353 K. The variation of a.c. conductivity with frequency follows the Jonscher’s universal power law. The temperature dependence of electrical conductivity suggests the semiconducting behaviour of the materials. 相似文献
9.
A new alternative system for the oxidation of secondary alcohols to ketones with DMSO/N2H4.H2O/I2/H2O/CH3CN in hydrated media has been developed. The system also selectively oxidizes the secondary alcoholic groups to the corresponding ketones in the presence of primary alcoholic groups present within the same molecule in moderate to very good yields at reflux temperature. 相似文献
10.
Theoretical insight of nitric oxide adsorption on neutral and charged Pdn (n = 1–5) clusters
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Pakiza Begum Pranjal Gogoi Bhupesh Kumar Mishra Ramesh Chandra Deka 《International journal of quantum chemistry》2015,115(13):837-845
Density functional theory (DFT) calculations within the framework of generalized gradient approximation have been used to systematically investigate the adsorption of nitric oxide (NO) molecule on neutral, cationic, and anionic Pdn (n = 1–5) clusters. NO coordinate to one Pd atom of the cluster by the end‐on mode, where the tilted end‐on structure is more favorable due to the additional electron in the π* orbital. On the contrary, in the neutral and cationic Pd2 system, NO coordinates to the bridge site of cluster preferably by the side‐on mode. Charge transfer between Pd clusters and NO molecule and the corresponding weakening of N? O bond is an essential factor for the adsorption. The N? O stretching frequency follow the order of cationic > neutral > anionic. Binding energy of NO on anionic clusters is found to be greater than those of neutral and cationic clusters. © 2015 Wiley Periodicals, Inc. 相似文献