Extraction of uranium(VI) with N,N,N′,N′-tetrabutylmalonamide and N,N,N′,N′-tetrahexylmalonamide

A new diamide N,N,N′,N′-tetrahexylmalonamide (THMA) was synthesized, characterized and used in the extraction of U(VI) from nitric acid solutions. N,N,N′,N′-tetrabutylmalonamide (TBMA) was also studied to test the steric hindrance. Factors affecting this extraction system, the concentration of the extractant, aqueous nitric acid and NaNO₃ and the temperature were investigated. The IR spectral study was also made of the extracted species.     

N′N′N pincer and N′N bidentate(pyrazolylpyridyl) Rh(I) complexes as catalyst precursors for hydroformylation of olefins

Transition Metal Chemistry - The industrial process of hydroformylation or the oxo process has been used for many years in the production of aldehydes from alkenes. Different metals have been used...     

N,N′-bis(2-Vinyloxyethyl)carbodiimide

Previously unreported N,N-bis(2-vlnyloxyethyl)carbodiimide was synthesized by the reaction of N,N -bis(2-vinyloxyethyl)thiourea with yellow mercuric oxide in CH₂Cl₂ at room temperature.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1897–1898, August, 1990.     

Substituierte N,N′-Bis(silyl)-cyclodisilazane

Zusammenfassung Die Spaltung von Cyclotri- und-tetrasilazanen mit Halogenwasserstoff oder mit Dimethyldihalogensilan (Schema 1, Rkk. 7 und 8) und die intermolekulare Kondensation von 1.3-Dihalogentetramethyldisilazanen durch Pyrolyse bzw. mit Triäthylamin oder auch mit Cyclosilazanen (Rkk. 11, 12) führt zu den N,N-Bis(dimethylhalogensilyl)-tetramethyl-cyclodisilazanen (I–III). Diese können über die Rkk. 13, 14–20 (Schema 2) und 21 in zahlreiche Derivate (IV–XIII) übergeführt werden.

---

Substituted N.N-bis(silyl)-cyclodisilazanes (chemistry of silicon-nitrogen compounds, XCVI)

Cleavage of cyclotri- and-tetrasilazanes with hydrogen halides or with dimethyldihalogenosilanes (scheme 1; equ. 7 and 8) and the intermolecular condensation of 1.3-dihalogenotetramethyldisilazanes by pyrolysis, in the presence of triethylamine, or with cyclosilazanes (equ. 11, 12), lead to the N.N-bis-(dimethylhalogenosilyl)-tetramethylcyclodisilazanes (I–III), which can be transformed via equ. 13, 14, 20 (scheme 2) and 21 into numerous derivatives (IV–XIII).

---

---

95. Mitt.:U. Wannagat, J. Herzig, P. Schmidt undM. Schulze, Mh. Chem.102, 1817 (1971).

---

a) Mit Auszügen aus der DissertationE. Bogusch, Techn. Hochschule Graz 1966, und b) nach Arbeiten vonP. Geymayer am Inst für Anorg. Chem. der Techn. Hochschule Graz, Sommer 1965.     

N,N′-Bis(trimethylsilylmethyl)thiocarbamide and N,N′-Bis(trimethylsilylmethyl)-λ6-thiocarbamide S,S-Dioxide

N,N′-Bis(trimethylsilylmethyl)-λ⁶-thiocarbamide S,S-dioxide was synthesized by oxidation of N,N′-bis(trimethylsilylmethyl)thiocarbamide with hydrogen peroxide. The synthesized dioxide is a less active reducing agent than previously studied S,S-dioxides of organosilicon thiocarbamides in which the silicon atom is separated from the thiocarbamide fragment by a -CH₂CH₂CH₂- bridge.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 912–914.Original Russian Text Copyright © 2005 by Vlasova, Grigor’eva, Voronkov.     

Infrared spectra of N2O-(ortho-D2)N and N2O-(HD)N clusters trapped in bulk solid parahydrogen

High-resolution infrared spectra of the clusters N2O-(ortho-D2)N and N2O-(HD)N, N=1-4, isolated in bulk solid parahydrogen at liquid helium temperatures are studied in the 2225 cm-1 region of the nu3 antisymmetric stretch of N2O. The clusters form during vapor deposition of separate gas streams of a precooled hydrogen mixture (ortho-D2para-H2 or HDpara-H2) and N2O onto a BaF2 optical substrate held at approximately 2.5 K in a sample-in-vacuum liquid helium cryostat. The cluster spectra reveal the N2O nu3 vibrational frequency shifts to higher energy as a function of N, and the shifts are larger for ortho-D2 compared to HD. These vibrational shifts result from the reduced translational zero-point energy for N2O solvated by the heavier hydrogen isotopomers. These spectra allow the N=0 peak at 2221.634 cm-1, corresponding to the nu3 vibrational frequency of N2O isolated in pure solid parahydrogen, to be assigned. The intensity of the N=0 absorption feature displays a strong temperature dependence, suggesting that significant structural changes occur in the parahydrogen solvation environment of N2O in the 1.8-4.9 K temperature range studied.     

Synthetic approaches to N(delta)-methylated L-arginine, N(omega)-hydroxy-L-arginine, L-citrulline, and N(delta)-cyano-L-ornithine

Nomega-Methylated arginines such as asymmetric dimethyl-L-arginine (ADMA) and monomethyl-l-arginine (NMMA) are known as potent physiological inhibitors of nitric oxide synthases (NOSs). To explore a possible physiological and pharmaceutical relevance of N(delta)-methylated analogues, a synthetic scheme had to be developed that would not lead to N(delta)-methyl-L-arginine only but also to its presumed metabolites of NOS catalysis. Two basic synthetic approaches have been pursued to obtain N(delta)-methylated derivatives of L-ornithine, L-citrulline, L-arginine, and N(omega)-hydroxy-L-arginine. A first attempt utilized conventionally protected L-ornithine, i.e., the tert-butyl ester and Boc-amine, and led to three end compounds in excellent yields. Simultaneous protection of the alpha-amino acid moiety by formation of boroxazolidinones, particularly by employing 9-borabicyclo[3.3.1]nonane (9-BBN-H), proved to be a convenient option to perform side chain modifications and led to all of the desired end compounds. Additionally, enantiomeric excess (ee, %) of crucial synthetic intermediates and end compounds was determined by chiral HPLC.     

N,N′-dialkylsubstituted Imidazolidine-2-thionecopper(I) complexes. X-ray analysis of chloro-bis(N,N′-dimethylimidazolidine-2-thione)copper(I)

Summary New complexes of copper(I) withN,N-dialkylsubstituted imidazolidine-2-thione ligands were prepared by reduction of CuX₂ (X = Cl or Br). The i.r. spectra show that in all the complexes the ligand coordinates through the sulphur atom. The crystal structure of chloro-bis(N,N-dimethylimidazolidine-2-thione)copper(I) has been determined from x-ray diffraction data. Crystals are monoclinic. space groupC ₂, with unit cell dimensions:a = 16.022(15),b = 9.942(10),c = 15.112(15) A, = 139.84(10)², Z = 4. The final R index is 5.2%. The copper coordination is trigonal, involving sulphur atoms of the two ligands and One chlorine atom. The steric effect of the two methyls imposes a rotation of the imidazolidine rings with respect to the coordination plane. The dihedral angle between the mean plane of thiourea moieties. parallel one with the other. and the coordination plane is 119.3°.This work was supported by the National Research Council (C.N.R.) of Rome.     

Gravimetrische Phosphorbestimmung mit N,N,N′,N′-Tetrakis-(2-hydroxybutyl)-äthylendiammoniumdiperchlorat

This reagent forms a sparingly soluble precipitate, [C₁₈H₄₀O₄N₂H₂]₃[P(Mo₃O₁₀)₄]₂ in presence of phosphate and molybdate in hydrochloric acid solution. The precipitate is well suitable for a gravimetric determination of phosphorus (factor 0.013190). Standard deviation was ± 0.3 mg for 93.94 mg and ± 0.6 mg for 1174,2 mg of precipitate. Fe, Mn, Cr, Co and Ni do not interfere up to a 500-fold excess.     

N,N,N＇,N＇-四丁基丙二酰胺萃取Tb(Ⅲ)的研究

取代酰胺类萃取剂因其易合成、分解产物易除去而不影响萃取工艺流程等优点,在核燃料后处理方面显示出很好的应用前景.国内外在该类萃取剂萃取铀(Ⅵ)、钍(Ⅳ)以及硝酸的性能研究方面已经做了大量工作[1,2],但对高放废液中共存稀土元素的萃取研究报道较少[3].     

Copper(II) complexes of 2-formyl-, 2-acetyl- and 2-benzoyl-pyridine N(4)-phenyl-, N(4)-o-methoxyphenyl-, N(4)-p-methoxy-phenyl- and N(4)-p-nitrophenylthiosemicarbazones

Summary Cu^II complexes of 2-formyl-, 2-acetyl- and 2-benzoylpyridine N(4)-phenyl-, N(4)-o-methoxyphenyl-, N(4)-p-methoxyphenyl- and N(4)-p-nitrophenyltniosemicarbazones, coordinated either as neutral or monoanionic ligands, have been prepared and characterized. I.r., electronic and e.p.r. spectra of the complexes, as well as ¹H-and ¹³C-n.m.r. spectra of the thiosemicarbazones, have been obtained. Both the thiosemicarbazones and their complexes show either modest or no growth inhibitory activity against Paecilomyces variotii. However, some of these thiosemicarbazones possess significant activity against a number of tumour cell strains.     

Extraction of uranium(VI) and thorium(IV) ions from nitric acid solutions by N,N,N′,N′-tetrabutyladipicamide

A new symmetrical diamide, the straight-chain alakyl substituted neutral tetrabutyladipicamide (TBAA) has been synthesized, characterized and used for the extraction of U(V) and Th(IV) from nitric acid solutions in a diluent composed of 50% 1,2,4-trimethylbenzene (TMB) and 50% kerosene (OK). Extraction distribution coefficients of U(VI) and Th(IV) as a function of aqueous nitric acid concentration, extractant concentration and temperature have been studied. Back-extraction of U(VI) and Th(IV) from organic phases by dilute nitric acid has been undertaken. From the data, the compositions of extracted species, equilibrium constants and enthalpies of extraction reactions have also been calculated.     

Zur Bestimmung von N,N′-Diphenyl-thioharnstoff (I)

Analytical and Bioanalytical Chemistry -