627-53-2Relevant academic research and scientific papers
UV vapor generation for determination of selenium by heated quartz tube atomic absorption spectrometry
Guo, Xuming,Sturgeon, Ralph E.,Mester, Zoltan,Gardner, Graeme J.
, p. 2092 - 2099 (2007/10/03)
A new vapor generation technique utilizing UV irradiation coupled with atomic absorption for the determination of selenium in aqueous solutions is described. In the presence of low molecular weight organic acid solutions, inorganic selenium(IV) is converted by UV irradiation to volatile selenium species, which are then rapidly transported to a heated quartz tube atomizer for detection by atomic absorption spectrometry. Optimum conditions for photochemical vapor generation and interferences from concomitant elements were investigated. Identification of the volatile products using cryotrapping GC/MS analysis revealed that inorganic selenium(IV) is converted to volatile selenium hydride, selenium carbonyl, dimethyl selenide, and diethyl selenide in the presence of formic, acetic, propionic, and malonic acids, respectively. In acetic acid solution, the efficiency of generation was estimated to be 50 ± 10%. No interference from Ni2+ and Co2+ at concentrations of 500 and 100 mg L-1, respectively, was evident. A detection limit of 2.5 μg L-1 and a relative sensitivity of 1.2 pg L-1 (1% absorption) with a precision of 1.2% (RSD, n = 11) at 50 pg L-1 were obtained.
Reaction of Mono- and Dihaloalkanes with Mixed Solutions of Chalcogens in Alkaline Reductive Systems
Deryagina,Grabel'nykh,Mamaseva
, p. 711 - 714 (2007/10/03)
Sufur-selenium, sulfur-tellurium, selenium-tellurium, and sulfur-selenium-tellurium mixtures readily dissolve in the hydrazine hydrate-alkali system to form chalcogenide anions. Alkylation of the latter with ethyl bromide results in preferential formation
New Routes to Poly(Alkylene Sulfidoselenides)
Deryagina, E. N.,Grabelnykh, V. A.,Russavskaya, N. V.,Alekminskaya, O. V.
, p. 1729 - 1733 (2007/10/03)
A procedure was developed for preparing mixed poly(alkylene sulfidoselenides) by simultaneous dissolution of sulfur and selenium in basic reducing systems NaOH (KOH)-N2H4 * H2O-H2O, followed by alkylation of the resulting solutions with bielectrophilic agents.
NEW ROUTE TO ORGANIC SELENIDES AND TELLURIDES
Korchevin, N. A.,Podkuiko, P. A.,Stankevich, V. K.,Deryagina, E. N.,Trofimov, B. A.
, p. 85 - 87 (2007/10/03)
A new simple and convenient synthetic route to organic chalcogenides R2Y (R = alkyl, allyl, benzyl; Y = Se, Te) is developed, which involves generation of Se2- and Te2- anions from Se and Te in the system KOH-hydrazine hydrate, where the latter plays the role of both the medium and reducing agent.Subsequent alkylation of the anions with the corresponding alkyl halides furnishes the target chalcogenides in almost 95percent yield.Alkyl chlorides react faster than alkyl bromides and alkyl iodides.
Electronic and steric effects in the dissociative displacement of thioethers from mixed phenyl(thioether)platinum(II) complexes
Alibrandi, Giuseppe,Minniti, Domenico,Scolaro, Luigi Monsù,Romeo, Raffaello
, p. 1939 - 1943 (2008/10/08)
A series of compounds of the type cis-[PtPh2L2], where L encompasses a wide range of thioethers of different steric and electron-donating characteristics, have been prepared and characterized. Most of these monomeric compounds exist in solution in equilibrium with the sulfur-bridged dimer [Pt2Ph4(μ-L)2] and the free thioether. Addition of small amounts of ligand in solution allows the stabilization of the monomeric form. Kinetic studies of the displacement of the thioethers with 2,2′-bipyridine (bpy) to yield [PtPh2(bpy)] in CH2Cl2 at 298.16 K, carried out in the presence of sufficient excess of [L] and [bpy] to ensure pseudo-first-order conditions, showed that the reactions follow a bivariate nonlinear rate law kobsd = a[bpy]/(b[L] + [bpy]) + c[bpy], which has the same form as that of similar systems for which a dissociative mechanism has been proposed. The reactivity decreases linearly with increasing σ-donor ability of the leaving thioether, with bulky substituents on sulfur playing an accelerating role. The relative sensitivities of the dissociative and associative processes to the inductive effects of the leaving group are compared and related to the degree of lengthening and weakening of the bond with the metal produced by the trans-activating group.
