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81.
A polynuclear complex [Cd(endc)(H2O)]n·nH2O (endc = endo-norbomene-cis5,6-dicarboxylate anion) has been synthesized by the hydrothermal reaction of cadmium nitrate tetrahydrate with endo-norbomene-cis-5,6-dicarboxylic acid in 1:1 molar ratio,and structurally characterized by single-crystal X-ray diffraction.It crystallizes in monoclinic,space group P21/c with a = 1.16471(7),b = 0.95334(7),c = 0.91109(9) nm,Z = 4,V= 1.01035(14)nm3,Dc.= 2.160 g/cm3,μ= 2.172 mm-1,F(000) = 648,R =0.0302 and wR = 0.0752.According to structural analysis,each Cd(Ⅱ) ion is coordinated to six O atoms from three endc anions and one water molecule,giving a distorted octahedral geometry.Two- dimensional layer arrangement of the title complex is constructed from the bridging nature of endc.It is worth notice that adjacent two-dimensional layers are joined together to form a three-dimensional supramolecular framework via intermolecular hydrogen bonding interactions. 相似文献
82.
Antoine Aboukais Elena A. Zhilinskaya Jean-Franois Lamonier Igor N. Filimonov 《Colloids and surfaces. A, Physicochemical and engineering aspects》2005,260(1-3):199-207
Oxygen adsorption experiments were performed on evacuated and prereduced CeO2/SiO2 and CeO2/Al2O3 catalysts with and without platinum. Considerable amounts of the superoxide radical ions were stabilized on all the samples. Signal parameters suggest Ce4+–O2− positioning for all detectable superoxide species. Physisorbed oxygen broadens O2− signal beyond detection for all the alumina-based samples, while the same procedure for all the silica-based samples did not change signal shape of O2− species. Detectable O2− species are localized in the bulk of ceria and the nature of support (silica or alumina) determines the number of oxygen vacancies and the rate of electron transfer. XRD data suggest that for alumina-based samples small and/or thin islands of ceria dominate, while comparatively large ceria particles are stabilized on the surface of silica-based samples with the same ceria content. Average size of ceria crystallites is still not determining factor and cannot account for the observed differences. Higher concentrations of paramagnetic species may be stabilized on alumina-based samples and thus, sensor-like behavior towards gaseous oxygen at room temperature was detected for them—oxygen admission reversibly changes superoxide lineshape. For silica samples, only minor changes of O2− lineshapes were typical upon the change of the partial pressure of oxygen at ambient and low temperatures. Addition of platinum has little effect on parameters of the O2− signal, except an enhancement of the superoxide decay in the reducing media. Possible site for O2− stabilization inside the lattice of CeO2 was proposed and relevance of the observed effects to the redox catalysis discussed. 相似文献
83.
In this paper, a separation method of the inorganic anions including I–, NO
2
–
, NO
3
–
, IO
3
–
and SCN– on the reversed-phase ion-pair chromatography with direct UV detection has been developed, and the limits of detection of these inorganic anions were determined. The effects of the organic modifier volume fraction and concentration of the ion-pair reagent on the retention of inorganic anions were discussed. 相似文献
84.
R. M. Lazorenko-Manevich A. N. Podobaev L. A. Sokolova 《Russian Journal of Electrochemistry》2007,43(1):42-50
Based on the model of spatial separation of the dissolution and passivation of hydrophilic metals, the effect of strong specific adsorption of anions on the shape of curves for the relaxation of anodic current of metals in acid solutions after switching an anodic activation pulse off is considered by using iron as an example. 相似文献
85.
应用抑制电导检测离子色谱法建立了准确快速测定磷酸二氢钠中无机阴离子含量的分析方法。样品经过简单溶解后即可上机分析,分析时间小于30min。实验结果表明,方法的重现性好、灵敏度高、操作简便易行,还可以推广应用到其他工业原料如磷酸钠、磷酸氢钙及磷酸等的测定。 相似文献
86.
Ireneusz Sowa Magdalena Wójciak-Kosior Piotr Drączkowski Maciej Strzemski Ryszard Kocjan 《Analytica chimica acta》2013
The new sorbent for non-suppressed ion chromatography based on silica gel coated with a film of polyaniline (PANI) was obtained in a process of in situ polymerization of aniline by oxidation with ammonium peroxydisulfate. Raman analyses performed using a Thermo Scientific DXR confocal Raman Microscope equipped with the Omnic 8 software from Thermo Fisher Scientific have proved a uniform distribution of PANI on the surface of chromatographic beads and in the pores of the particle. 相似文献
87.
Dr. Kyohei Otsuka Naozumi Matsumoto Dr. Shintaro Ishida Prof. Dr. Soichiro Kyushin 《Angewandte Chemie (International ed. in English)》2015,54(27):7833-7836
The radical anion of octa‐tert‐butyloctasilacubane was generated and isolated. The EPR spectrum showed the satellites due to the tertiary 13C nuclei of the eight tert‐butyl groups. The X‐ray crystallographic analysis showed that the Si? Si bonds are shortened and the Si? C bonds are elongated compared with those of octa‐tert‐butyloctasilacubane. These results are well explained by the distribution of an unpaired electron in the singly occupied molecular orbital (SOMO). 相似文献
88.
Tadashi Sugano Mohamedally KurmooStephen J. Blundell William HayesSerge Vilminot 《Polyhedron》2011,30(18):3202-3205
Three divalent transition-metal (Co, Ni and Cu) complexes with the organic anion, 1,2,4-triazolato (tr), as a ligand molecule were prepared by means of hydrothermal syntheses and their magnetic properties were investigated by SQUID magnetometry. The Co(tr)2 and Cu(tr)2 complexes exhibit long range ordering below 8 and 30 K, respectively, while the Ni(tr)2 complex does not show any magnetic phase transition down to 1.8 K. The magnetization isotherms of Co(tr)2 and Cu(tr)2 measured at 2.0 K show hysteresis loops with the coercive fields of 0.5 and 4.7 kOe, respectively. At temperatures higher than about 50 K, the temperature dependence of the magnetic susceptibility of Co(tr)2, Ni(tr)2 and Cu(tr)2 follows the Curie-Weiss law with the Curie constants of 2.95, 0.945 and 0.420 emu K mol−1 and the Weiss temperatures of −62, −74 and −97 K, respectively. These results suggest that the magnetically ordered phases observed in Co(tr)2 and Cu(tr)2 at low temperatures come from antiferromagnetic interactions resulting in canted arrangements of magnetic moments of the transition-metal cations. We discuss here the magnetic interactions in these transition-metal complexes by referring the results of the magnetization measurements. 相似文献
89.
Mechanical properties of anion exchange membranes by combination of tensile stress–strain tests and dynamic mechanical analysis 下载免费PDF全文
Riccardo Narducci J.‐F. Chailan A. Fahs Luca Pasquini Maria Luisa Di Vona Philippe Knauth 《Journal of Polymer Science.Polymer Physics》2016,54(12):1180-1187
The thermomechanical properties of anion exchange polymers based on polysulfone (PSU) quaternized with trimethylamine (TMA) or 1,4‐diazabicyclo[2.2.2]octane (DABCO) and containing hydroxide or chloride anions by tensile stress–strain tests and dynamic mechanical analysis (DMA) have been determined. The reported mechanical properties included the Young's modulus, tensile strength, and elongation at break from tensile tests and the storage and loss modulus and glass transition temperature from DMA. The anion exchange membranes behaved as stiff polymers with Young's modulus in the order of 1 GPa, relatively with high strength (about 30 MPa) and low elongation at break (around 10%) was observed. Tensile tests were also made with membranes exchanged with hydrogen‐carbonate and carbonate anions to control the absence of important carbonation of the OH form. The glass transition temperatures were of the order of 150 °C (PSU‐TMA) or 200 °C (PSU‐DABCO) for the hydroxide form, confirmed by differential scanning calorimetry; they increase further by about 50 K, when hydroxide ions are replaced by chloride. This result and the increase of the storage modulus could be interpreted by the higher hydration of hydroxide ions and the plasticizing effect of water, which reduced the Van der Waals interactions between the macromolecular chains. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1180–1187 相似文献
90.
Dr. Flávio Figueira Igor Marques Dr. Andreia S. F. Farinha Prof. Dr. Augusto C. Tomé Prof. Dr. José A. S. Cavaleiro Prof. Dr. Artur M. S. Silva Prof. Dr. Jonathan Sessler Prof. Dr. Vítor Félix Prof. Dr. João P. C. Tomé 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14349-14355
A novel sapphyrin derivative was obtained from the reaction between a free‐base sapphyrin and dimethyl acetylenedicarboxylate (DMAD). The formation of the new compound involved a double aza‐Michael addition of two pyrrolic NH groups to a DMAD molecule, with the formation of a disubstituted ethano bridge. The NMR spectral data reveal a product with an unsymmetrical structure; DFT calculations provided support for a structure in which the ethano bridge links two adjacent pyrrole units. The present study provides a seemingly unprecedented example of an N,N′‐dinucleophile reacting with DMAD to form a heterocyclic compound in which the two N‐atoms are linked to the two sp3 carbon atoms derived from a substituted acetylene. 相似文献