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131.
Sreemanta Mitra Amrita Mandal Anindya Datta Sourish Banerjee Dipankar Chakravorty 《Journal of magnetism and magnetic materials》2012
Nanosheets of nickel with thickness equal to 0.6 nm have been grown within the interlayer spaces of Na-4 mica. The sheets are made up of percolative clusters of nanodisks. Magnetization characteristics indicate a superparamagnetic behavior with a blocking temperature of 428 K. The magnetic anisotropy constant as extracted from the coercivity data has been found to be higher than that of bulk nickel by two orders of magnitude. This is ascribed to a large aspect ratio of the nickel nanophase. The Bloch exponent is also found to be considerably different from that of bulk nickel because of a size effect. The Bloch equation is still found to be valid for the two dimensional structures. 相似文献
132.
It is well-known that matrix effects in high performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) can seriously compromise quantitative analysis and affect method reproducibility. Paired ion electrospray ionization (PIESI) mass spectrometry is an approach for analyzing ultra-low levels of anions in the positive ion mode. This approach uses a structurally optimized ion pairing reagent to post-column associate with the anionic analyte, subsequently forming positively charged complexes. These newly formed complex ions are often more surface-active as compared to either the native anion or the ion pairing reagent. No studies have examined whether or not the PIESI approach mitigates matrix effects. Consequently, a controlled study was done using five analytes in highly controlled and reproducible synthetic groundwater and urine matrices. In addition, two different mass spectrometers (linear ion trap and triple quadrupole) were used. Compared to the negative ion mode, the PIESI-MS approach was less susceptible to matrix effects when performed on two different MS platforms. Using PIESI-MS, less dilution of the sample is needed to eliminate ionization suppression which, in turn, permits lower limits of detection and quantitation. 相似文献
133.
《Journal of Coordination Chemistry》2012,65(22):3914-3922
Two octacyanometallate-based NiII–MIV [M?=?Mo(1), W(2)] bimetallic assemblies chelated with tetradentate macrocyclic ligands have been synthesized by slow diffusion and characterized structurally. In both complexes, M and Ni centers acting as linker and connector, respectively, are connected by M–CN–Ni–NC–M linkages to form a 3-D diamond-type topological network. Magnetic behaviors of both complexes show a very weak antiferromagnetic interaction between NiII ions mediated by the diamagnetic [M(CN)8]4? bridges. 相似文献
134.
135.
《Journal of Coordination Chemistry》2012,65(14):1209-1215
The synthesis, molecular structure and spectroscopic and magnetic properties of (NH4)2(15-crown-5)3[Ni(mnt)2]2 (mnt?=?maleonitriledithiolate dianion) are reported. The most notable structural feature of (NH4)2(15-crown-5)3[Ni(mnt)2]2 is that the ions form a stacked structure with well-separated columns along the c and a axes. Variable temperature magnetic susceptibility measurements indicate strong antiferromagnetic interactions in the complex. 相似文献
136.
137.
Nickel aluminate (NiAl2O4) and doped nickel aluminate (Ni1-xMxAl2O4; M = Mg, Zn, Cu; x = 0.1) were prepared by sol-gel method using citric acid. The synthesized compounds were analyzed by various techniques such as powder XRD, FTIR, SEM-EDAX and UV-DRS. The lattice parameter was found to increase with the copper, zinc and magnesium doping in nickel aluminate. The band gap was decreased from 3.0 eV (NiAl2O4) to 2.9 (zinc doped), 2.7 eV (magnesium doped) and increased to 3.1 eV in the case of copper doping. The catalytic study was carried out for a cationic (methylene blue) and an anionic dye (methyl orange). The percentage degradation of methyl orange using Zn0.1Ni0.9Al2O4 and Mg0.1Ni0.9Al2O4 was found to be 92% (180 min) and 96% (90 min). 93% (120 min) and 97% (120 min) degradation of methylene blue was observed using zinc doped and magnesium doped nickel aluminate respectively. These results are comparatively higher than its parent analogue (94% (180 min) degradation against methyl orange and 91% (120 min) against methylene blue). Whereas the percentage degradation was found to be less in the case of Cu0.1Ni0.9Al2O4 (83% (180 min) against methyl orange and 90% (120 min) against methylene blue). 相似文献
138.
《Journal of Coordination Chemistry》2012,65(16):2788-2801
Nickel(II) complexes of N-(di-alkyl-carbamothioyl)-4-nitrobenzamide (alkyl?=?ethyl or n-propyl) have been synthesized and characterized by infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry. The structures of bis[N-(diethylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2a) and bis[N-(dipropylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2b) have been determined by X-ray crystallography. FTIR and NMR of the nickel complexes showed the absence of the N–H proton resonance and the N–H stretch and shift of ν C=O and ν C=S as expected. Both complexes have been used as single-source precursors for the deposition of nickel sulfide nanostructured thin films by aerosol-assisted chemical vapor deposition. The nanostructured thin films were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and atomic force microscopy. 相似文献
139.
《Analytical letters》2012,45(17):1497-1512
Abstract Hexamethylphosphoramide (HMPA) gives, in aqueous solutions in the presence of SCN? ions, complexes with many metal ions, which absorb in the visible region of spectrum. The spectra have been studied in function of ligand concentration and pH for Co, Ni and Fe complexes. For the Co complex an equation was found that describes the behaviour of the absorption vs. SCN? and HMPA concentration. Absorption follows Lambert-Beer law and can be used for analytical determinations. Analysis of solutions containing Ni and Co in various ratios of concentration has been performed and results are discussed. Co, Ni and Fe content of an alloy has been measured by this way. 相似文献
140.
Template-induced synthetic routes for azacalix[n](2,6)pyridines (n = 3, 4) have been elaborated. The proton and nickel ion served as the efficient template for the cyclization reactions, and the presence of the templates preferentially afforded the cyclic trimers and tetramers in moderate to good yields, respectively. The compatibility of the cyclic tetramer with nickel ion was also confirmed by X-ray crystallography. 相似文献