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141.
Stefan Scholz Michael Bolte Matthias Wagner Hans‐Wolfram Lerner Dr. 《无机化学与普通化学杂志》2007,633(8):1199-1204
Syntheses and Properties of Di‐tert‐butylphosphides [M(PtBu2)2]2 (M = Zn, Hg) and [Cu(PtBu2)]4 The phosphides [M(PtBu2)2]2 (M = Zn, Hg) and [Cu(PtBu2)]4 are accessible from reaction of LiPtBu2 with ZnI2, HgCl2 and CuCl, respectively. [M(PtBu2)2]2 (M = Zn, Hg) are dimers in the solid state. X‐ray structural analyses of these phosphides reveal that [M(PtBu2)2]2 (M = Zn, Hg) contain four‐membered M2P2‐rings whereas [Cu(PtBu2)]4 features a planar eight‐membered Cu4P4‐ring. Degradation reaction of LiPtBu2(BH3) in the presence of HgCl2 results in the dimeric phosphanylborane BH3 adduct [tBu2PBH2(BH3)]2. X‐ray quality crystals of [tBu2PBH2(BH3)]2 (monoclinic, P21/n) are obtained from a pentane solution at 6 °C. According to the result of the X‐ray structural analysis, the O2‐oxidation product of [Hg(PtBu2)2]2, [Hg{OP(O)(tBu)OPtBu2}(μ‐OPtBu)]2, features in the solid state structure two five‐membered HgP2O2‐rings and a six‐membered Hg2P2O2‐ring. Herein the spiro‐connected Hg atoms are member of one five‐membered and of the six‐membered ring. 相似文献
142.
Dieter Scholz 《Monatshefte für Chemie / Chemical Monthly》1984,115(5):655-657
Enamines of cyclic ketones were -alkylthiolated in good yields by simply refluxing them with alkyl 4-methylbenzenethiosulfonates and triethylamine in acetonitrile. 相似文献
143.
In this review the combination of voltammetric methods of analysis with separation techniques, such as electrochemical separations, extractive separations, chromatography, electrochromatography, electrophoresis, volatilization and coprecipitation is critically discussed. Based on available publications and their own experience, the authors try to evaluate different separation techniques in view of future developments, paying special attention to extraction methods. For organic analysis, chromatography and electrophoresis with voltammetric detection are considered to be especially attractive while for stripping analysis, major progress is expected to be made in the development of electrodes and electronic equipment. Extraction, coprecipitation and volatilization will be of minor significance. 相似文献
144.
In TDPAC studies of the electric quadrupole interaction in RuxSc1–x alloys two different electric fieldgradients (EFG) have been observed at the site of99Ru: Vzz(I)=12.6·1017 V/cm2 and Vzz(II)=18.9·1017 V/cm2. The corresponding relative fractions f(I) and f(II), respectively, vary with the Ru concentration x. For low concentrations x<0.01 most nuclei (f(I)0.8) experience the smaller EFG Vzz(I). At x=0.01, however, the fraction f(I) goes abruptly to zero and Vzz(II) becomes dominant. In view of these results the previous interpretation of Vzz(II) as the EFG of dilute Ru on substitutional Sc sites can no longer be maintained. The Ru-Sc configurations producing these EFG's have not yet been identified. In the intermetallic compound Ru2Sc the interaction is completely different, in RuSc3, however, similar values have been observed. 相似文献
145.
Widmann A Kahlert H Petrovic-Prelevic I Wulff H Yakhmi JV Bagkar N Scholz F 《Inorganic chemistry》2002,41(22):5706-5715
Substitutional solid solutions of metal hexacyanometalates in which low-spin iron(III) and cobalt(III) ions populate the carbon-coordinated sites were synthesized and studied by powder diffraction including Rietveld refinement, cyclic voltammetry of immobilized microparticles, diffuse reflection vis-spectrometry, and magnetization techniques. The continuous solid solution series of potassium copper(II), potassium nickel(II), and iron(III) [(hexacyanoferrate(III))(1-x)(hexacyanocobaltate(III))(x)] show that the substitution of low-spin iron(III) by cobalt(III) in the hexacyanometalate units more strongly affects the formal potentials of the nitrogen-coordinated copper(II) and high-spin iron(III) ions than those of the remaining low-spin iron(III) ions. In the case of copper(II) and iron(III) [(hexacyanoferrate(III))(1-x)(hexacyanocobaltate(III))(x)] the peak currents decrease much more than can be explained by stoichiometry, indicating that the charge propagation is slowed by the substitution of low-spin iron(III) by cobalt(III). The Rietveld refinement of all compounds confirmed the structure initially proposed by Keggin for Prussian blue and contradicts the structure described later by Ludi. The dependencies of lattice parameters on composition exhibit in all series of solid solutions studied similar, although small, deviations from ideality, which correlate with the electrochemical behavior. Finally, a series of solid solutions of the composition KNi(0.5)(II)Cu(0.5)(II)[Fe(III)(CN)(6)](1-x)[Co(III)(CN)(6)](x), where both the nitrogen- and carbon-coordinated metal ions are mixed populated and were synthesized and characterized. These are the first examples of solid solutions of metal hexacyanometalates with four different metal ions, where both the nitrogen- and the carbon-coordinated sites possess a mixed population. 相似文献
146.
Hans G. Fliri Dieter Scholz Anton Stütz 《Monatshefte für Chemie / Chemical Monthly》1979,110(1):245-247
Construction of the carbon-skeleton of (R,S)-muscone was achieved by reacting methyllithium with the dianion of cyclopentadecanedione-1,3, itself accessible by hydration of cyclopentadecanediyne-1,3.
Synthese von (R,S)-Muscon (Kurze Mitteilung) Short communication
Zusammenfassung Die Konstruktion des Kohlenstoffgerüstes von (R,S)-Muscon gelingt durch Reaktion des Dianions von Cyclopentadecandion-1,3, das durch Hydratisierung von Cyclopentadecandiin mit Methyllithium erhältlich ist.相似文献
147.
A sampling flash apparatus for recording weak transient absorptions in the microsecond range is described. Two methods for the evaluation of first- and second-order rate constants from mixed-order plots are briefly discussed. The concentration dependence of the lifetime of anthracene in its excited triplet state has been investigated in cyclohexane at room temperature. It is assumed that the observed decrease in triplet lifetime with increasing anthracene concentration is due to impurity quenching and not due to triplet excimer formation. 相似文献
148.
On the Possibility of Planar Tetracoordination of the Fourth Main Group Elements (C, Si, Ge) Semiempirical MO calculations (CNDO/2, EHT) have been used to examine the ability of silicon, carbon, and germanium to form planar tetracoordinated compounds. The calculations have been performed for the tetrahedral ground state structures (Td – symmetry) as well as for the artificial planar structures (D4h – symmetry) of the compounds CH4, SiH4, GeH4, and CF4, SiF4, GeF4. A comparison between the tetrahedral and planar species showed, that all planar species are less stable. Furthermore they have larger bond distances and their bonds are stronger polarized. The possibility of the examined compounds to form planar structures increases with growing atomic number of the central atom and with increasing electronegativity of the substituents. 相似文献
149.
Gold nanoparticle synthesis in graft copolymer micelles 总被引:4,自引:0,他引:4
G. Carrot J. C. Valmalette C. J. G. Plummer S. M. Scholz J. Dutta H. Hofmann J. G. Hilborn 《Colloid and polymer science》1998,276(10):853-859
An amphiphilic poly(acrylic acid)/polystyrene graft copolymer (PAA-g-PS) has been used to form “nanoreactors” for the synthesis
of gold clusters. Such copolymers tend to form stable micelles in non-polar organic solvents where the poly(acrylic acid)
chains constitute the core, and the polystyrene chains, the shell. In the present study, the micellar structure of PAA-g-PS
in toluene has been demonstrated by dynamic light scattering and transmission electron microscopy (TEM).
The subsequent preparation of gold-graft copolymer composites involved the introduction of gold chloride (AuCl3), either in powder form or previously dissolved in ether, into the micellar cores of the PAA-g-PS in toluene. The gold salt
was then reduced by ultraviolet (UV) irradiation of the emulsion, or of dried cast films. TEM and ultraviolet-visible (UV/Vis)
spectroscopy were used to characterize the resulting composites. Gold particles of less than 5 nm in diameter were observed
in all cases, but the size distribution and the spatial arrangement of the clusters in the cast films were modified when diethyl
ether was used to introduce AuCl3 into the PAA-g-PS micellar cores. This was thought to be due to enhanced nucleation of the gold particles and partial disruption
of the micellar cores in the presence of diethyl ether.
Received: 21 January 1998 Accepted: 11 June 1998 相似文献
150.
A. Scholz 《Monatshefte für Chemie / Chemical Monthly》1908,29(5):439-450
Ohne Zusammenfassung 相似文献