The nonanuclear coordination compound [MoIV{(CN)FeIII(3-methyl-saldptn)}8]Cl4 exhibits multiple spin transitions (3-methyl-saldptn = N,N′-bis(3′′-methyl-2′′-hydroxy-benzyliden)-1,7-diamino-4-azaheptane). This spin crossover cluster is bound via a self-assembled monolayer onto a two dimensional array gold surface. M?ssbauer spectroscopy indicates that the thermally and optically induced spin crossover of the compound is maintained. Thereby, the foundation for its potential practical application (e.g. in the field of information storage) was laid. 相似文献
Nanocrystalline manganese aluminate (MnAl2O4) has been synthesized by Pechini and sequential homogenous precipitation methods and the results have been compared. The Taguchi L4 statistical design was utilized to optimize the production of MnAl2O4 nanoparticles by Pechini method. The MnAl2O4 nanocrystallites obtained by Pechini and sequential homogenous precipitation methods had the average particle size of 26.5 and 49.5 nm, respectively. The products were characterized with X-ray diffraction, laser light scattering, thermogravimetry analysis, Fourier transform infrared, UV–visible, energy dispersive X-ray, scanning electron microscope and inductively coupled plasma analyses. The photocatalytic activities of MnAl2O4 nanoparticles synthesized by two methods were investigated using aqueous solution of methylene blue under irradiation of visible light. 相似文献
Alkyl halides are efficiently converted to their corresponding S-alkyl thioacetates under mild and nonaqueous conditions, using polymer-supported sodium thioacetate as a new polymeric reagent at room temperature in high yields and purity. The spent polymeric reagent can be removed quantitatively by filtration and pure products can be obtained by evaporation of the solvent. The spent polymeric reagent can be regenerated and reused several times without its activity changing appreciably. 相似文献
Theoretical investigation on hydrazine (N2H4) adsorption on Ni(111) was done by using density functional theory. Stability and mechanism of hydrazine adsorption in anti, gauche and cis conformation on nickel surface were studied. Charge transfer between lone-pair orbital and d-band was found to stabilize the anti-conformation as the most stable conformation, in contrast with hydrazine in the gas-phase where gauche conformation is more favored. However, the derived anti-bonding state between adsorbate and substrate is partially occupied due to the spin-polarization in the local states near the Fermi level and thus contributes in weakening the bonding. The stable adsorption structure was further verified by comparing the calculated vibrational frequencies with HREELS measurement results. The results were found to be in agreement with experimental results. It was also found that the adsorption in cis-conformation is a transition state as evident from the existence of imaginary frequency on its lowest vibrational mode which belongs to NH2 torsional movement around N–N axis. 相似文献
We present a biographical sketch of Alenush Terian, the first Iranian woman physicist, who was known as the Iranian Solar Mother, since she founded the first solar telescopic observatory in Iran. She taught and carried out astronomical research for three decades with inadequate resources but with unflinching devotion, motivated by a strong desire to propagate scientific education and research in her country. 相似文献
An inside-needle extraction method was developed through thermal polymerization of atrazine-molecularly imprinted polymer (MIP) on the internal surface of a stainless steel hollow needle, which was oxidized and silylated. The fabricated coating (MIP layer) for the needle was durable and showed very good chemical and thermal stability. It could be mounted on a glass syringe and be directly coupled with gas chromatographic (GC) systems. The parameters being effective on the coating and extraction processes, namely nature of oxidizing agent, silylation time, nature and amount of porogen, template-to-MIP components ratio, polymerization time and temperature, sample volume, flow rate, pH and ionic strength of the sample were investigated and optimized. The extraction needle showed high selectivity as well as a great extraction capacity for triazines. The extraction of atrazine, simazine, cyanazine, ametryn, prometryn and terbutryn using the fabricated extraction needle and followed by GC analysis resulted in detection limits of 2.6, 21, 24, 32, 38 and 42 ng mL−1, respectively. The fabricated needle proved to be applicable to the analysis of real samples by comparing the results obtained for non-spiked and spiked samples of grape juice, tap water and groundwater.
An efficient, one-pot, three-component procedure for the synthesis of a small library of new chiral spirooxindolopyrrolizidines with high regio-, diastereo-, and enantioselectivity, from the 1,3-dipolar cycloaddition of azomethine ylides and optically active cinnamoyl oxazolidinone is described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the absence of any Lewis acids. The oxazolidinone chiral auxiliary is removed in a non-destructive manner. The reaction mechanism is discussed on the basis of the assignment of the absolute configuration of the cycloadducts, and on theoretical calculations. 相似文献