The separation of some Bi- and tervalent cations on zirconium phosphate columns

Summary On small columns filled with the inorganic cation-exchanger zirconium phosphate, Zn²⁺-Cd²⁺ were quantitatively and Ni²⁺-Co²⁺ partly separated. The exchanger was in the NH₄+ form, and 0.5–4N NH₄Cl served as eluent. With the exchanger in the H+ form, U0₂ ²⁺ was separated from bivalent cations and ferric iron by stepwise elution with 0.1, 0.5 and 4N HCl solutions.

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Zusammenfassung An kleinen Säulen des anorganischen Kationenaustauschers Zirkoniumphosphat wurden Zn²⁺ und Cd²⁺ quantitativ, Ni²⁺ und Co²⁺ teilweise getrennt. Der Austauscher lag in der NH₄+-Form vor, 0,5-bis 4-n Ammoniumchlorid diente als Eluent. Mit der H+-Form des Austauschers wurde UO₂ ²⁺ von zweiwertigen Kationen und von Fe³⁺ durch schrittweise Elution mit 0,1-, 0,5- und 4-n Salzsäure getrennt.

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Résumé On a séparé Zn²⁺-Cd²⁺ quantitativement et Ni²⁺-Co²⁺ partiellement sur de petites colonnes remplies de phosphate de zirconium comme échangeur minéral cationique. L'échangeur se trouvait sous forme NH₄+ et l'on a pris NH₄Cl 0,5-4N comme éluant. Avec l'échangeur sous forme H⁺, on a séparé UO₂ ²⁺ des cations bivalents et de l'ion ferrique par élution graduelle avec des solutions chlorhydriques 0,1, 0,5 et 4N.

     

Selective electrophilic monofluorination on rings of various sizes using elemental fluorine

Elemental fluorine substitutes tertiary unactivated hydrogens in an electrophilic mode. This unorthodox substitution depends on the atomic charge density, on the hydrogen atom and on the p-orbital contribution on the CH bond. This is demonstrated by reacting F₂ with tertiary CH bonds located on rings of various sizes, producing the corresponding tertiary fluorine derivatives.     

Isolation of the novel dirhodium(II/II) thiolate compound Rh(2)(eta(1)-C(6)H(5)S)(2)(mu-C(6)H(5)S)(2)(bpy)(2)

The reaction of the anticancer active compound [Rh(2)(mu-O(2)CCH(3))(2)(bpy)(2)(CH(3)CN)(2)][BF(4)](2) (1) (bpy = 2,2'-bipyridine) with NaC(6)H(5)S under anaerobic conditions yields Rh(2)(eta(1)-C(6)H(5)S)(2)(mu-C(6)H(5)S)(2)(bpy)(2).CH(3)OH (2), which was characterized by UV-visible, IR, and (1)H NMR spectroscopies as well as single-crystal X-ray crystallography. Compound 2 crystallizes as dark red platelets in the monoclinic space group C2/c with cell parameters a = 20.398(4) A, b = 11.861(2) A, c = 17.417(4) A, beta = 108.98 degrees, V = 3984.9(14) A(3), Z = 4. The main structural features are the presence of a [Rh(2)](4+) core with a Rh-Rh distance of 2.549(2) A bridged by two benzene thiolate ligands in a butterfly-type arrangement. The axial positions of the [Rh(2)](4+) core are occupied by two terminal benzene thiolates. Cyclic voltammetric studies of 2 reveal that the compound exhibits an irreversible oxidation at +0.046 V in CH(3)CN, which is in accord with the fact that the compound readily oxidizes in the presence of O(2). The fact that this unusual dirhodium(II/II) thiolate compound is formed under these conditions is an important first step in understanding the metabolism of dirhodium anticancer active compounds with thiol-containing peptides and proteins.     

Thermal behaviour of some 2-benzylamino-2-deoxyheptonic acids

The thermal behaviour of some 2-benzylamino-2-deoxyheptonic acids obtained from 2-benzylamino-2-deoxy-D-glycero-L-gluco, 2-benzylamino-2-deoxy-D-glycero-D-ido and 2-benzylamino-2-deoxy-D-glycero-D-taloheptononitriles (reported) previously has been studied in air (static atmosphere) and N₂ (dynamic atmosphere, flow rate 200 ml/min).

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Zusammenfassung Das thermische Verhalten einiger aus 2-Benzylamino-2-desoxy-D-glycero-L-gluco-, 2-Benzylamino-2-desoxy-D-glycero-D-ido und 2-Benzylamino-2-desoxy-D-glycero-D-talo-heplononitril (kürzlich beschrieben) erhaltenen 2-Benzylamino-2-desoxy-heptonsäuren wurde ín Luft (statische Atmosphäre) und N₂ (dynamische Atmosphäre, Strömungsgeschwindigkeit 200 ml/min) untersucht.

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( 200 /) 2--2- , 2--2---uepo-L, 2-2- ---- 2-2--- -- 2--2----ma .

     

Support vector machines and neural networks used to evaluate paper manufactured using Eucalyptus globulus

Using advanced machine learning techniques as an alternative to conventional double-entry volume equations, a regression model of the inside-bark volume (dependent variable) for standing Eucalyptus globulus trunks (or main stems) has been built as a function of the following three independent variables: age, height and outside-bark diameter at breast height (DBH). The experimental observed data (age, height, outside-bark DBH and inside-bark volume) for 142 trees (E. globulus) were measured and a nonlinear model was built using a data-mining methodology based on support vector machines (SVM) and multilayer perceptron networks (MLP) for regression problems. Coefficients of determination and Furnival’s indices indicate the superiority of the SVM with a radial kernel over the allometric regression models and the MLP.     

Synthesis and properties of new fluorene-containing copolymer via the catalytic dehydrocoupling reaction of 9,9-dipropargyl fluorene and 4,4′-diphenyl-2,6-dibromo-dithieno-[3,2-b:2′,3′-d]silole

ABSTRACT

New fluorene-containing copolymer was prepared via the catalytic dehydrocoupling reaction of 9,9-dipropargylfluorene and 4,4′-diphenyl-2,6-dibromo-dithieno-[3,2-b:2′,3′-d]silole in 44% yield. The resulting polymer was completely soluble in common organic solvents. The thermal behaviors and optical properties of the resulting polymer were measured and discussed. The chemical structure of polymer was characterized by NMR, IR, and UV-visible spectroscopies. The polymer showed characteristic wide UV-visible absorption band and blue PL maximum value at 440 nm, which is corresponding photon energy of 2.82 eV. The quantum yield (6.44%) of poly(DPF-DTS) was found to be 5 times higher than that of poly(DPF-bithiophene)).