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121.
Treatment of the ligand 6‐aza‐2‐thiothymine (ATT, HL, 1 ) with palladium chloride in methanol forms the ionic complex [(HL)4Pd]Cl2·8MeOH ( 2 ), while its reaction with palladium iodide in same solvent produces the neutral complex trans‐[(HL)2PdI2]·2MeOH ( 3 ) in high yields. The reaction of 1 with Na2[PdCl4] in the presence of sodium acetate in a molar ratio of 2:1:2 and with platinum(II) chloride in presence of sodium acetate led to the dimer tetranuclear complexes [(L4Pd2)NaCl]2·8MeOH ( 4 ) and [L4Pt2Cl2]·6MeOH·H2O ( 5 ). The latter is the first PtIII complex of the ligand. All complexes were characterized by elemental analyses and IR spectroscopy and the crystal structures of 2 , 3 , 4 and 5 are determined by single‐crystal X‐ray diffraction. Crystal data for 2 at ?80 °C: triclinic space group , a = 1006.6(1), b = 1006.9(1), c = 1158.1(1) pm, α = 85.20(1)°, β = 83.84(1)°, γ = 88.91(1)°, Z = 1, R1 = 0.0278; for 3 at ?80 °C: triclinic space group , a = 490.5(1), b = 977.2(2), c = 1116.8(2) pm, α = 90.26(1)°, β = 102.33(1)°, γ = 96.08(1)°, Z = 1, R1 = 0.0394; for 4 at ?80 °C: orthorhombic space group Ccca, a = 1791.7(2), b = 1874.1(2), c = 2044.0(1) pm, Z = 4, R1 = 0.0341 and for 5 at ?80 °C: monoclinic space group P21/c, a = 1464.3(1), b = 2003.7(1), c = 1368.5(1) pm, β = 95.66(1)°, Z = 4, R1 = 0.0429. 相似文献
122.
The carbodiphosphorane CO2 adduct O2CC(PPh3)2 ( 1a ) reacts with [(CO)5W(THF)] and [(CO)3W(NCEt)3] to produce the complexes [(CO)5W{η1‐O2CC(PPh3)2}] ( 2 ) and [(CO)4W{η2‐O2CC(PPh3)2}] ( 3 ), respectively. Whereas in 2 the betain‐like ligand is coordinated at the tungsten atom in a monodentate manner, in 3 it acts as a chelating ligand with formation of a WO2C four‐membered ring. As a by‐product during the reaction with the acetonitrile adduct also some crystals of the hydrolysis product [HC(PPh3)2]2[W6O19] · 3C2H4Cl2 (4 · 3C2H4Cl2) were isolated. All compounds could be characterized by X‐ray analyses and the usual spectroscopic methods. 相似文献
123.
Zusammenfassung Durch Messung der Verteilungskoeffizienten wird der Nachweis erbracht, daß Chelataustauscher durch Zusatz von Metalloxinaten, z. B. von Al- und Ba-Oxinat, während der Kondensation der Harze selektiver gemacht werden können. In dieser Arbeit werden die pH-lg ex-kurven verschiedener Oxinatharze diskutiert. Die Form der Kurven wird aus dem Zusammenwirken von Komplexbildung, Donnan-Verteilung und Austauschvorgängen mit Carboxylgruppen abgeleitet. Die Steigungen der pH-lg ex-kurven werden als Maß für die mittlere Ligandenzahl verwendet. Die Selektivität der Austauscher wird durch die pH100-Werte charakterisiert. Damit wird der Nachweis erbracht, daß die sterische Anordnung des Oxins im Harz für die Selektivität mitverantwortlich ist.
Mit 8 Abbildungen
1. Mitt. (s. S. 1050) wird im folgenden I genannt. 相似文献
By measuring the distribution coefficients it is shown that the selectivity of chelate resins can be raised by adding metaloxinates of Al and Ba, e.g., during the condensation. The pH-lg ex-curves of various oxinate resins are discussed in this paper. The shape of the curves is derived from the interaction between complex formation, Donnan-distribution and exchange with carboxylic groups. The slope of the pH-lg ex-curves is used as measure for the average ligand number. The selectivity of the resins is characterized by the pH100 (pH value at ex=100). From these experiments it follows conclusively, that the steric arrangement of the oxine in the resin is responsible for the selectivity.
Mit 8 Abbildungen
1. Mitt. (s. S. 1050) wird im folgenden I genannt. 相似文献
124.
New Entrance Optics for Solar Spectral UV Measurements 总被引:2,自引:0,他引:2
The investigation of the impact of solar UV radiation on the biosphere requires spectral measurements of solar UV radiation of high accuracy. However, the accuracy of current measurements is limited, and this can partly be attributed to the entrance optics of the instruments used for these examinations. The angular response of spectro-radiometers measuring spectral global UV irradiance should be given by the cosine of the incidence angle. In-tercomparison campaigns have shown that deviations from this ideal cosine response lead to uncertainties in solar measurements of more than 10%. Here we present recently developed entrance optics that reduce these uncertainties to ±4% in the UV. The new entrance optics have been characterized with respect to their angular response, transmission, weather durability, fluorescence and dependence of the angular response on wavelength and polarization. Solar spectroradiometric measurements carried out with the new optics were compared with simultaneously performed measurements of a second spectroradiometer that was equipped with a conventional diffuser. The deviations of up to 12% between both systems are quantitatively explained to within 3%. 相似文献
125.
Reisner E Arion VB Rufińska A Chiorescu I Schmid WF Keppler BK 《Dalton transactions (Cambridge, England : 2003)》2005,(14):2355-2364
Reaction of the antitumor complex trans-[Ru(III)Cl4(Hind)2]- (Hind = indazole) with an excess of dimethyl sulfoxide (dmso) in acetone afforded the complex trans,trans,trans-[Ru(II)Cl2(dmso)2(Hind)2] (1). Two other isomeric compounds trans,cis,cis-[Ru(II)Cl2(dmso)2(Hind)2] (2) and cis,cis,cis-[Ru(II)Cl2(dmso)2(Hind)2] (3) have been obtained on refluxing cis-[Ru(II)Cl(2)(dmso)(4)] with 2 equiv. of indazole in ethanol and methanol, respectively. Isomers 1 and 2 react with acetonitrile yielding the complexes trans-[Ru(II)Cl2(dmso)(Hind){HN=C(Me)ind}].CH3CN (4.CH3CN) and trans,cis-[Ru(II)Cl2(dmso)2{HN=C(Me)ind}].H2O (5.H2O), respectively, containing a cyclic amidine ligand resulting from insertion of the acetonitrile C triple bond N group in the N1-H bond of the N2-coordinated indazole ligand in the nomenclature used for 1H-indazole. These are the first examples of the metal-assisted iminoacylation of indazole. The products isolated have been characterized by elemental analysis, IR spectroscopy, UV-vis spectroscopy, electrospray mass-spectrometry, thermogravimetry, differential scanning calorimetry, 1H NMR spectroscopy, and solid-state 13C CP MAS NMR spectroscopy. The isomeric structures of 1-3 and the presence of a chelating amidine ligand in 4 and 5 have been confirmed by X-ray crystallography. The electrochemical behavior of 1-5 and the formation of 5 have been studied by cyclic voltammetry. 相似文献
126.
90% of the alkaline extracts contained substances giving positive reaction with iodoplatinate and Dragendorff reagents. One of these could be identified as nicotine. Methods for differentiating beween morphine and nicotine are mentioned and it is pointed to the possibility of erroneous results in the thin-layer chromatographic investigation of urinary extracts of smokers of basic pharmaceuticals. 相似文献
127.
128.
Barron JA Glazier S Bernhard S Takada K Houston PL Abruña HD 《Inorganic chemistry》2003,42(5):1448-1455
The absorption and emission spectra, excited-state lifetimes, quantum yields, and electrochemical measurements have been obtained for a new series of chiral complexes based on three different chiral 2,2':6',2' '-terpyridine ligands, (-)-ctpy, (-)-[ctpy-x-ctpy], and (-)-[ctpy-b-ctpy], with one, two, or multiple Ru metal centers. The room-temperature absorption and emission maxima of [[((-)-ctpy)Ru]-(-)-[ctpy-b-ctpy]-[Ru((-)-ctpy)]](PF(6))(4) and ((-)-[ctpy-b-ctpy])-[[Ru((-)-[ctpy-b-ctpy])](PF(6))(2)](n) were shifted to lower energies and also exhibited significantly longer luminescence lifetimes when compared to [Ru((-)-ctpy)(2)](PF(6))(2), [[((-)-ctpy)Ru]-(-)-[ctpy-x-ctpy]-[Ru((-)-ctpy)]](PF(6))(4), and ((-)-[ctpy-x-ctpy])-[[Ru((-)-[ctpy-x-ctpy])](PF(6))(2)](n). In terms of their electrochemical behavior, all of the complexes studied exhibited one Ru-centered and two ligand-centered redox waves and the [[((-)-ctpy)Ru]-(-)-[ctpy-x-ctpy]-[Ru((-)-ctpy)]](PF(6))(4), ((-)-[ctpy-x-ctpy])-[[Ru((-)-[ctpy-x-ctpy])](PF(6))(2)](n), and ((-)-[ctpy-b-ctpy])-[[Ru((-)-[ctpy-b-ctpy])](PF(6))(2)](n)() complexes were found to electrodeposit upon ligand-based reduction. The difference between the formal potentials of the Ru-centered and the first ligand-centered (least negative) waves corresponded linearly with the changes in the observed emission energies. The shifts in energy are discussed using a particle-in-a-box model, and the luminescence lifetimes are discussed in terms of the structure of the excited-state manifold. 相似文献
129.
The thermal properties, i.e., heat capacity, enthalpy, entropy, and Gibbs function, and the transition behavior of the copolymer system of 4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid have been studied based on differential scanning calorimetry. The heat capacities of the glass, crystal, and anisotropic melt are shown to be largely additive on a molar basis. Additivity is lost in the two transition regions, glass transition and disordering transition. Isothermal crystallization experiments on the copolymers revealed the existence of two types of crystals which melt at high temperature (fast-grown crystals) and low temperature (slowly grown crystals). The ATHAS computation method is used to bring heat capacities of the solid state into agreement with approximate frequency spectra. The changes in heat capacity at the glass transitions occur at 434°K for the poly(oxy-1,4-benzoyl) [33.2 J/(K mol)] and at 420°K for poly(oxy-2,6-naphthoyl) [46.5 J/(K mol)]. The copolymers have a transition range of above 100°K. The anisotropic melt is linked to the well-known condis state of poly(oxy-1,4-benzoyl) by a continuous changes in disorder and mobility without an additional first-order transition. 相似文献
130.