Complexes ML12 and ML22, with M = FeII, CoII, NiII, and 1,3-bis(2-R-tetrazol-5-yl)triazenide ligands L1 (R = Me) and L2 (R = tBu), have been synthesized by the reaction of corresponding 1,3-bis(2-R-tetrazol-5-yl)triazenes with metal(II) salts in basic media and characterized by IR, UV–Vis spectroscopy, thermal and X-ray diffraction analyses. Both 1,3-bis(2-R-tetrazol-5-yl)triazenes were found to deprotonate on coordination and act as tridentate chelating ligands forming distorted MN6 octahedra around metal(II) cations. 相似文献
The article presents the findings of microscopic and electrochemical studies of electrooxidation of bismuth particle of varying sizes. Bismuth particles were immobilized on the surface of indifferent carbon containing screen-printed electrodes. The calculations and experimental studies demonstrated that the transition from macroparticles to nanoparticles caused a shift of the maximum current potential of bismuth oxidation into the area with more negative potentials. A positive correlation between experimental and calculated data confirms once again a relevant application of the earlier proposed mathematical model and the possible use of the shift of the maximum current potential of electrooxidation to describe electrochemical activity and energy properties of metal nanoparticles. 相似文献
In this study the problem of finding the conformal mapping from a sphere onto a plane with a given scale function independent
of longitude is solved for an arbitrary spherical domain. The obtained results are compared with the well-known projections
used in cartography and geophysical fluid dynamics. The problem of minimization of the distortion under conformal mappings
is solved for domains in the form of the spherical disk. The distortions of some extensively used conformal mappings are compared
with the distortions of orthogonal mappings. 相似文献
Monoclinic KY(WO4)2:Pr3+, Tm3+:KY(WO4)2:Er3+, Yb3+ single crystals are grown by low-gradient Czochralski technique. Stimulated emission at 1.0223μm wavelength in the new lasing 1D2→3F3 channel of Pr3+ ions in KY(WO4)2 at room temperature under Xe-flashlamp pumping is excited. Full sets of Stark-level energies for Pr3+ ions in KY(WO4)2 and KGd(WO4)2 crystals at 77 K are determined. 4f2-4f2 intensity-transitions for the KY(WO4)2:Pr3+ are analyzed preliminarily. All observed at present and earlier one-micron Pr3+-ion, induced transitions in the 1D2→3F3 and 1D2→3F4 channels are identified. In yttrium and gadolinium sensitized-tungstates a two-micron (3H4→3H6) low-threshold generation of Tm3+ ions at cryogenic temperatures is achieved.All authors cooperate with the Joint Open Laboratory for Laser Crystals and Precise Laser Systems at the Institute of Crystallography and Institute of Laser Physics, Russian Academy of Sciences. 相似文献
Herein, we describe the synthesis of molecular scaffolds consisting of medium‐sized fused heterocycles using amino acids, which are some of the most useful building blocks used by nature as well as chemists to create structural diversity. The acyclic precursors were assembled by using traditional Merrifield solid‐phase peptide synthesis, and cyclization was carried out through acid‐mediated tandem endocyclic N‐acyliminium ion formation, followed by nucleophilic addition with internal nucleophiles. The synthesis of molecular scaffolds consisting of seven‐, eight‐, and nine‐membered rings proceeded with full stereocontrol of the newly generated stereogenic center in most cases. 相似文献
Considerable efforts have been devoted to the development of rapid and sensitive methods allowing the detection of viral nucleic acid. We herein describe an assay for identification of a specific influenza sequence. The suggested method was based on isolation using paramagnetic particles coupled with electrochemical detection of isolated product. Peptide nucleic acid (PNA) was used as a probe for hybridization and identification of the influenza-derived specific sequence. The use of PNA can show numerous benefits: PNA probe is not degradable by enzymes and the duplex of PNA with RNA/DNA is more thermostable and more resistant to pH changes than DNA/DNA or RNA/RNA duplexes. This PNA probe assay can be applied as a magnetically guidable tool for detection of DNA/RNA samples under different conditions.
CE with MS detection is a hyphenated technique which greatly improves the ability of CE to deal with real samples, especially with those coming from biology and medicine, where the target analytes are present as trace amounts in very complex matrices. CE-MS is now almost a routine technique performed on commercially available instruments. It faces currently a tremendous development of the technique itself as well as of its wide application area. Great interest in CE-MS is reflected in the scientific literature by many original research articles and also by numerous reviews. The review presented here has a general scope and belongs to a series of regularly published reviews on the topic. It covers the literature from the last 2 years, since January 2008 till June 2010. It brings a critical selection of related literature sorted into groups reflecting the main topics of actual scientific interest: (i) innovations in CE-ESI-MS, (ii) use of alternative interfaces, and (iii) ways to enhance sensitivity. Special attention is paid to novel electrolyte systems amenable to CE-MS including nonvolatile BGEs, to advanced CE separation principles such as MEKC, MEEKC, chiral CE, and to the use of preconcentration techniques. 相似文献