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排序方式: 共有214条查询结果,搜索用时 156 毫秒
51.
Bijan Etemadi Abdol Abadi Rex A. Palmer Brian W. Fitzsimmons 《Journal of chemical crystallography》1988,18(1):35-53
The crystal structure of bis (NN-di(n-propyl)dithiocarbamato iron(III) iodide, FeIII(S2CN6H14)2I, has been determined by the heavy-atom method and refined toR=0.055 for 3487 reflections withI(hkl)>3I(hkl). The crystals are triclinic,C¯1,Z=8,a=27.644(6),b=19.186(4),c=8.694(2) Å,=87.79(1),=88.72(1), =101.87(2)°. The I-Fe bond lengths are different in the two moleculesA andB in the asymmetric unit, having values of 2.642 Å (2.655) and 2.612 Å (2.634) respectively (libration-corrected values given in parentheses). The measured effective magnetic moment
eff3.89 BM, independent of temperature (93-353K), suggests a spinS of 3/2 with three unpaired electrons for FeIII. 相似文献
52.
Synthesis,Structure, Bonding,and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2}2{μ‐η2:η2‐B2H4}] and [{Cp*M(CO)2}2B2H2M(CO)4], M=Mo,W
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Dr. Bijan Mondal Ranjit Bag Sagar Ghorai Dr. K. Bakthavachalam Prof. Eluvathingal D. Jemmis Prof. Sundargopal Ghosh 《Angewandte Chemie (International ed. in English)》2018,57(27):8079-8083
The reaction of [(Cp*Mo)2(μ‐Cl)2B2H6] ( 1 ) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO)2}2{μ‐η2:η2‐B2H4}] ( 2 ). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged Cs structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum–alkyne complex [{CpMo(CO)2}2C2H2]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO)4] fragment, [{Cp*Mo(CO)2}2 B2H2W(CO)4] ( 3 ) was isolated upon treatment with [W(CO)5?thf]. Compound 3 shows the intriguing presence of [B2H2] with a short B?B length of 1.624(4) Å. We isolated the tungsten analogues of 3 , [{Cp*W(CO)2}2B2H2W(CO)4] ( 4 ) and [{Cp*W(CO)2}2B2H2Mo(CO)4] ( 5 ), which provided direct proof of the existence of the tungsten analogue of 2 . 相似文献
53.
The separation of a complex mixture of inorganic and organic anions by ion chromatography–capillary electrophoresis using a cationic polymer added to the background electrolyte and indirect UV detection has been studied. The addition of unmodified polymer to an electrolyte suitable for indirect detection resulted in the appearance of a system peak due to the counter-anion on the polymer and while the position of the analytes relative to this system peak could be changed, this was found to be an unacceptable approach for mixtures of large numbers of analytes. Although conversion of the polymer to replace the counter-ion with the indirect UV detection probe ion simplified the system, this approach restricted the flexibility of the system because the probe and polymer concentration were necessarily linked. This limitation could be overcome by selecting the appropriate type of probe ion, with probes having a low ion-exchange selectivity coefficient providing greater retention of analytes than probes with a high ion-exchange selectivity coefficient. Three electrolyte systems with different probes (benzoate, chromate and phthalate) were modelled using a previously derived migration equation and this was used to optimise the electrolyte composition to enable the separation of a mixture of 24 inorganic and organic anions within 7 min. The electrolyte composition was then optimised for the analysis of anions in Bayer liquor with the final separation selectivity being substantially improved for selected key analytes. 相似文献
54.
Precise measurements of the electrical conductances of solutions of potassium thiocyanate (KCNS), ammonium thiocyanate (NH4CNS), sodium nitrate (NaNO3) and ammonium nitrate (NH4NO3) in 2-ethoxyethanol (EE) at temperatures 35, 40, 45 and 50,∘C are reported. The conductance data have been analyzed by the 1978 Fuoss conductance equation. A thermodynamic analysis of the ionic association processes has also been made and the Coulombic forces are found to play a major role in the association processes. The ionic contributions to the limiting equivalent conductances have been determined using the reference electrolyte method. Strong association was found for all these electrolytes in this solvent medium. The cations are found to be substantially solvated in 2-ethoxyethanol, whereas the anions appear to have only weak interaction with the solvent molecules. 相似文献
55.
John Koenitzer Bijan Khazai Jacob Hormadaly Robert Kershaw Kirby Dwight Aaron Wold 《Journal of solid state chemistry》1980,32(1):128-129
The orthorhombic α-PbO2 phase of FeNbO4 was prepared and its photoelectronic properties measured: Sintered disks were shown to be n type and gave a resistivity of 40 Ω-cm. Measurements of the photoresponse gave a flat-band potential between 0.1 and 0.4 V vs SCE at a pH of 8.5 and an optical band gap of 2.08(2) eV. Several higher-energy band gaps at 2.68(2), 2.94(2), 3.24(2), and 4.38(2) eV were also determined. There appears to be an enhancement of the quantum efficiency due to the presence of [FeO6] active centers while retaining the fundamental characteristics of the [NbO6] octahedra. 相似文献
56.
Summary A group of mixed-tris chelates of osmium(III) and osmium(IV) of type [OsAQ2]0/1 + [HA = glycine (glyH), picolinic acid (PicH) and quinaldic acid (qndH); HQ = 8-quinolinol] were prepared and characterized by physicochemical, magnetic and spectroscopic methods. The complexes exhibit several spin-allowed and spin-forbidden absorption bands and shoulders in the 200–700 nm region. The new chelates are electroactive and display nearly reversible OsIV-OsIII and OsIII-OsII couples in the ca. –1.1 to +0.3 V range versus s.c.e. The stability of metal oxidation states is discussed in terms of the electrochemical results. 相似文献
57.
58.
Optics is regarded undoubtedly a potential and successful candidate in information and data processing because of its inherent
parallelism. In last few decades several all-optical data processors, algebraic processors, arithmetic processors are proposed.
Here in this communication the authors propose a completely new scheme for implementing binary data arithmetic in 2’s Complement
method which is the most advantageous among all other established subtraction methods. To implement it we use non-linear material
massively. 相似文献
59.
60.
Precise conductance measurements of solutions of lithium chloride, lithium bromide, lithium iodide, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, tetrabutylammonium bromide, and tetrabutylammonium tetraphenylborate in N,N-dimethylacetamide are reported at 25°C in the concentration range 0.005–0.015 mol-dm–3. The conductance data have been analyzed by the 1978 Fuoss conductance equation in terms of the limiting molar conductance (0), the association constant (K
a), and the association diameter (R). The limiting ionic conductances have been estimated from an appropriate division of the limiting molar conductivity of the reference electrolyte Bu4NBPh4. Slight ionic association was found for all these salts in this solvent medium. The results further indicate significant solvation of Li+ion, while the other ions are found to be unsolvated in N,N-dimethylacetamide. 相似文献