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91.
The paper presents the principles and advantages of a technique combining high performance liquid chromatography and hydride
generation atomic absorption spectrometry (HPLC-HGAAS) applied to speciation analysis of inorganic species of arsenic As(III)
and As(V) in ground water samples. With separation of the arsenic species on an ion-exchange column in the chromatographic
system and their detection by the hydride generation atomic absorption spectrometry, the separation of the analytical signals
of the arsenic species was excellent at the limits of determination of 1.5 ng/ml As(III) and 2.2 ng/ml As(V) and RSD of 4.3%
and 7.8% for the concentration of 25 ng/ml. The hyphenated technique has been applied for determination of arsenic in polluted
ground water in the course of the study on migration of micropollutants. For total arsenic concentration two independent methods:
HGICP-OES and HGAAS were used for comparison of results of real samples analysis. 相似文献
92.
Speciation of inorganic arsenic by electrochemical hydride generation atomic absorption spectrometry 总被引:11,自引:0,他引:11
A simple procedure was developed for the speciation of inorganic arsenic by electrochemical hydride generation atomic absorption spectrometry (EcHG–AAS), without pre-reduction of As(V). Glassy carbon was selected as cathode material in the flow cell. An optimum catholyte concentration for simultaneous generation of arsine from As(III) and As(V) was 0.06 mol l−1 H2SO4. Under the optimized conditions, adequate sensitivity and difference in ratio of slopes of the calibration curves for As(III) and As(V) can be achieved at the electrolytic currents of 0.6 and 1 A. The speciation of inorganic arsenic can be performed by controlling the electrolytic currents, and the concentration of As(III) and As(V) in the sample can be calculated according to the equations of absorbance additivity obtained at two selected electrolytic currents. The calibration curves were linear up to 50 ng ml−1 for both As(III) and As(V) at 0.6 and 1 A. The detection limits of the method were 0.2 and 0.5 ng ml−1 for As(III) and As(V) at 0.6 A, respectively. The relative standard deviations were of 2.1% for 20 ng ml−1 As(III) and 2.5% for 20 ng ml−1 As(V). The method was validated by the analysis of human hair certified reference material and successfully applied to speciation of soluble inorganic arsenic in Chinese medicine. 相似文献
93.
Pt电极上吸附原子对仲丁醇电催化氧化性能的影响 总被引:1,自引:0,他引:1
运用电化学循环伏安和石英晶体微天平研究了HClO4溶液中仲丁醇在Pt电极及以Sb和S吸附原子修饰的Pt(Pt/Sbad和Pt/Sad)电极上的电催化氧化过程 .从电极表面质量变化可以看出 ,仲丁醇的氧化与电极表面的氧物种有着极其密切的关系 .Pt电极表面Sb吸附原子可在较低的电位下吸附氧 ,明显提高仲丁醇的氧化活性 .与Pt电极相比 ,Sb吸附原子修饰的Pt电极使仲丁醇氧化的峰电位负移约 10 0mV .相反 ,Pt电极表面S吸附原子的氧化会消耗表面氧物种 ,抑制仲丁醇的氧化 .从电极表面质量变化提供了吸附原子电催化作用的数据 相似文献
94.
Joseph Grobe Duc Le Van Franz Immel Marianne Hegemann Bernt Krebs Mechtild Lge 《无机化学与普通化学杂志》1996,622(1):24-34
Reactive E = C(pp)π-Systems. XLII [1]. Novel Coordination Compounds of 2-(Diisopropylamino)-1-phosphaethyne: [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}], [(Ph3P)2Pt{η2-(iPr2NCP)}], and [Co2(CO)6{η2-μ2-(iPr2NCP)}] 2-(Diisopropylamino)-phosphaethyne iPr2N? C?P ( 2 ) reacts with the Ni(0)-complexes [Ni(1,5-cyclooctadiene)2] and [Ni(CO)3(1-azabicyclo[2.2.2]octane)], respectively, to give the novel complex [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}] ( 5 ), with the 1,3-diphosphacyclobutadiene derivative and 2 (side-on) as π-ligands. The molecular structure of 5 determined by X-ray diffraction on single crystals proves the spin systems and rotational barriers deduced from NMR-data (1H, 13C-, 31P). The PC distances of the four-membered ring of 1.817(2) and 1.818(2) Å – as expected – are considerably longer than the PC bond of the η2-coordinated phosphaalkyne 2 [1.671(2) Å]. – In the reactions of 2 with [(Ph3P)2Pt(C2H4)] or [Co2(CO)8] the ligand properties of 2 resemble those of alkynes affording the complexes [(Ph3P)2Pt{η2-(iPr2NCP)}] ( 7 ) with side-on coordinated 2 and [Co2(CO)6{η2-μ2-(iPr2NCP)}] with 2 acting as a 4e donor bridge in quantitative yield. In attempts to prepare copper(I) complexes of the aminophosphaalkyne 2 by reaction with CuCl or CuI the only isolable product formed in reasonable amounts under the influence of air and moisture is the 1 λ3, 3 λ5-diphosphetene (iPr2N) ( 10 ) (isolated yield: ca. 20%). The crystal structure analysis of 10 indicates a strong structural relationship to the diamino-2-phosphaallyl cation [Me(iPr2N)]+ ( 12 ), the 1,3-diphosphacyclobutadiene ligand (iPr2NCP)2 in the binuclear complex [{η1, μ2-(iPr2NCP)2}Ni2(CO)6] ( 3a ) as well as to the heterocycles (dme)2LiOE2′ (E′ = S, 11a ; E′ = Se, 11b ) prepared by Becker et al. [11b, 35]. 相似文献
95.
D. N. Kravtsov V. M. Pachevskaya A. S. Peregudov E. I. Fedin 《Russian Chemical Bulletin》1995,44(7):1311-1315
A number of compounds of the type oftrans-4-FC6H4Pt(PAr3)2SC6H4F-4, where Ar is a substituted phenyl group, have been prepared starting from the corresponding chlorides. By exchange reactions oftrans-4-FC6H4Pt[P(C6H4F-4)3]2SC6H4F-4 with the above-mentioned compounds or Ar3P,trans-4-FC6H4Pt[P(C6H4F-4)3][PAr3]SC6H4F-4 have been generated in solution. For the latter compounds, the effect of Ar3P oncis- andtrans-ligands has been studied by the19F NMR technique. It has been shown that thecis- andtrans-effects of Ar3P run parallel and are well described by pK
a
values and ionization potentials of the unshared electron pair in Ar3P, as well as by 0 constants of the aryl groups.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1359–1363, July. 1995. 相似文献
96.
A. V. Makarycheva-Mikhailova S. I. Selivanov N. A. Bokach V. Yu. Kukushkin P. F. Kelly A. J. L Pombeiro 《Russian Chemical Bulletin》2004,53(8):1681-1685
Reactions of the platinum(IV) nitrile complexes [PtCl4(RCN)2] (R = Me, CH2Ph, Ph) with 1,2- and 1,4-PhS(=NH)C6H4SPh in CH2Cl2 afforded addition products of sulfimides and coordinated nitriles, viz., the [PtCl4{NH=C(R)N=S(Ph)(C6H4SPh)}2] complexes. The latter were isolated in 75—90% yields and characterized by elemental analysis, positive-ion FAB mass spectrometry, IR spectroscopy, and 1H and 13C1H NMR spectroscopy. The temperature dependence of the 1H NMR spectra of the model [PtCl4{NH=C(R)N=SPh2}2] complexes (R = Me, Et) in CD2Cl2 studied in a temperature range from +40 to -70 °C demonstrated that E—Z isomerization of the ligands is a dynamic process in a range from +40 to -10 °C. The activation free energy of this process was calculated.Published in Russian in Izvestiya Akademii Nauk.
Seriya Khimicheskaya, No. 8, pp. 1618–1622, August, 2004. 相似文献
97.
Sellmann D Hille A Heinemann FW Moll M Reiher M Hess BA Bauer W 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(17):4214-4224
The reactions of [Ru(N2)(PR3)(‘N2Me2S2’)] [‘N2Me2S2’=1,2‐ethanediamine‐N,N′‐dimethyl‐N,N′‐bis(2‐benzenethiolate)(2?)] [ 1 a (R=iPr), 1 b (R=Cy)] and [μ‐N2{Ru(N2)(PiPr3)(‘N2Me2S2’)}2] ( 1 c ) with H2, NaBH4, and NBu4BH4, intended to reduce the N2 ligands, led to substitution of N2 and formation of the new complexes [Ru(H2)(PR3)(‘N2Me2S2’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH3)(PR3)(‘N2Me2S2’)] [ 3 a (R=iPr), 3 b (R=Cy)], and [Ru(H)(PR3)(‘N2Me2S2’)]? [ 4 a (R=iPr), 4 b (R=Cy)]. The BH3 and hydride complexes 3 a , 3 b , 4 a , and 4 b were obtained subsequently by rational synthesis from 1 a or 1 b and BH3?THF or LiBEt3H. The primary step in all reactions probably is the dissociation of N2 from the N2 complexes to give coordinatively unsaturated [Ru(PR3)(‘N2Me2S2’)] fragments that add H2, BH4?, BH3, or H?. All complexes were completely characterized by elemental analysis and common spectroscopic methods. The molecular structures of [Ru(H2)(PR3)(‘N2Me2S2’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH3)(PiPr3)(‘N2Me2S2’)] ( 3 a ), [Li(THF)2][Ru(H)(PiPr3)(‘N2Me2S2’)] ([Li(THF)2]‐ 4 a ), and NBu4[Ru(H)(PCy3)(‘N2Me2S2’)] (NBu4‐ 4 b ) were determined by X‐ray crystal structure analysis. Measurements of the NMR relaxation time T1 corroborated the η2 bonding mode of the H2 ligands in 2 a (T1=35 ms) and 2 b (T1=21 ms). The H,D coupling constants of the analogous HD complexes HD‐ 2 a (1J(H,D)=26.0 Hz) and HD‐ 2 b (1J(H,D)=25.9 Hz) enabled calculation of the H? D distances, which agreed with the values found by X‐ray crystal structure analysis ( 2 a : 92 pm (X‐ray) versus 98 pm (calculated), 2 b : 99 versus 98 pm). The BH3 entities in 3 a and 3 b bind to one thiolate donor of the [Ru(PR3)(‘N2Me2S2’)] fragment and through a B‐H‐Ru bond to the Ru center. The hydride complex anions 4 a and 4 b are extremely Brønsted basic and are instantanously protonated to give the η2‐H2 complexes 2 a and 2 b . 相似文献
98.
Navnath S. Gavande 《Tetrahedron》2006,62(17):4201-4204
CaH2 was been found, for the first time, as a mild reducing agent to generate thiophenolate anion from Ph2S2 in N-methyl-2-pyrrolidone (NMP) for deprotection of aryl alkyl ethers. Excellent chemoselctivity was observed for substrates having chloro and nitro groups without displacement of the chlorine atom and the nitro group. Selective ether cleavage took place in the presence of α,β-unsaturated carbonyl and nitro groups without reduction and conjugate addition (to the α,β-unsaturated carbonyl group). 相似文献
99.
V. V. Gritsenko O. A. D'yachenko P. Cassoux A. I. Kotov E. E. Laukhina C. Faulmann E. B. Yagubskii 《Russian Chemical Bulletin》1993,42(7):1149-1151
A neutral metal complex, [Pt(dddt)2]° (1), has been obtained by oxidation of the [Pt(dddt)2]– anion with excess (Bu4N)AuBr4 in nitrobenzene. Crystallographic data for 1a=17.854(9) Å,b=18.409(9) Å,c=4.717(5) Å, =68.83(2)°, space group P21/n,Z=4,d
calc=2.55 g/cm3. In1 two independent centrosymmetric [Pt(dddt)2]° molecules are packed in stacks that form layers parallel to the (110) plane. The molecules of1 in the layers have shortened S...S contacts 3.491(9) Å, and 3.594(10) Å. The average bond lengths Pt-S 2.242(7) Å, S-C 1.71(2) Å and C=C 1.40(3) Å, together with the square-planar coordination of Pt in PtS4, suggest considerable conjugation in the metal cycles.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1207–1209, July, 1993. 相似文献
100.
I. V. Korol’kov A. I. Gubanov K. V. Yusenko I. A. Baidina S. A. Gromilov 《Journal of Structural Chemistry》2007,48(3):486-493
Several non-equilibrium solid solutions belonging to the platinum-osmium systems Os0.9Pt0.1, Os0.8Pt0.2, Os0.5Pt0.5, Os0.7Pt0.3, Os0.75Pt0.25 are prepared and studied. The thermal decomposition of [Pt(NH3)4][OsCl6] in the hydrogen and helium atmosphere is investigated. It is found that the Pt0.5Os0.5 solid solution develops through the formation of (NH4)2[OsCl6] and a metallic phase based on Pt. The crystal structure of a double complex salt [Pt(NH3)4][OsCl6] is studied (X8-APEX Bruker, 1508 independent reflections, R = 2.04%). Crystal data for PtOsN4Cl6H12 are: a = 11.6216(5) Å, b = 11.0016(5) Å, c = 10.3819(5) Å, V = 1327.4(1) Å3, space group Cmca, Z = 4, d x = 3.333 g/cm3. The coordination polyhedron around Os is octahedral: 〈Os-Cl〉 2.357 Å, ∠Cl-Os-Cl 89.5–90.5°, while around Pt it is square-planar: Pt-N 2.046 Å, ∠ N-Pt-N 89.59° and 90.41°. 相似文献