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991.
The overall stability constantsK
1 andK
2 of NdNO
3
2+
and Nd(NO3)
2
+
complexes were determined (K
1=1.77;K
2=1.28) using an extraction method with tri-n-butyl phosphate as the extractant. The ratio 1/2 of the stepwise stability constants is discussed. It was established that the Nd(NO3)
2
+
complex was an outer-sphere ion pair.
Die Assoziation von Nitrat-Ion mit Nd3+
Zusammenfassung Mittels einer Extraktionsmethode wurden die StabilitätskonstantenK 1 undK 2 von NdNO 3 2+ - und Nd(NO3)+-Komplexen bestimmt (K 1=1.77;K 2=1.28; Tri-n-butylphosphat als Extraktionsmittel). Das Verhältnis 1/2 der stufenweisen Stabilitätskonstanten wird diskutiert. Es stellte sich heraus, daß der Nd(NO3)+-Komplex als ein Outer-Shere-Ionenpaar vorliegt.相似文献
992.
J. C. Evans K. R. N. Rao S. K. Jackson C. C. Rowlands M. D. Barratt 《Journal of separation science》1985,8(12):829-830
Radicals generated in linoleic acid and deuterated linoleic acid have been trapped by the spin trap 2-methyl-2-nitroso-propane (MNP) and identified by electron spin resonance (ESR) and ENDOR spectroscopy. The formation of two distinct secondary alkyl radical adducts (one conjugated, the other non-conjugated, as shown by their UV absorption spectra) was demonstrated by 11, 11-dideuterio-9-cis-12-cis-linoleic acid using HPLC and ESR spectroscopy. 相似文献
993.
Four new compounds having nine cluster electrons and cores of the types Mo3OCl3, Mo3OBr3, and W3OCl3 are reported. Compound (1) prepared by reduction of [Bu4N][Mo3OCl6(OAc)3] in THF with metallic zinc, was shown by X-ray crystallography to be Mo3OCl4(OAc)3 (THF)2 (1). It forms crystals in space groupP21 with unit cell dimensionsa=9.472(2) Å,b=13.546(4) Å,c=9.652(2) Å, =101.70(2)°,V=1201(1) Å3,Z=2. The [Mo3(3-O)(-Cl)3]4+ core is surrounded by three -O2CCH3 anions, one Cl–, and two THF and has Mo-Mo distances of 2.620(1) Å, 2.613(1) Å, and 2.530(1) Å, with the shortest bond between the two Mo atoms to which the THF molecules are coordinated. Compounds [Bu4N]2 [Mo3OBr6(O2CCH3)3] · Me2CO, (2) and [Mo3OBr3(O2CCH3)3(PMe3)3]3 · BF4, (3) are the first two nine-electron Mo3 species with a [Mo3(3-O) Br3]4+ core. Both were obtained by zinc reduction of [Mo3OBr6(O2CCH3)3]– in the presence of (NBu4) Br (2) or PMe3 and NaBF4 (3), and each was characterized crystallographically. Compound (2) crystallized in space group Cc with unit cell dimensionsa=25.037(5) Å,b=12.827(2) Å,c=21.484(4) Å, =122.96(1)0,V=5790(3) Å3,Z=4. While the anion has no crystallographically required symmetry, its virtual symmetry is C3v
. The Mo-Mo distances are 2.619(2) Å, 2.610(3) Å, 2.644(2) Å, with a mean value of 2.624[14] Å. Compound (3) crystallized in space groupP21/c with unit cell dimensionsa=10.846(2) Å,b=25.033(5) Å,c=12.641(5) Å, =94.74(2)0,V=3420(2) Å3,Z=4. The cation occupies a general position but has virtual C3v
symmetry, with Mo-Mo distances of 2.601(2) Å, 2.610(2) Å, 2.627(2) Å, with a mean value of 2.613[14] Å. Thus the anionic and cationic Mo3 clusters in (2) and (3), respectively, have average Mo-Mo distances that are equal within experimental error. Compound (4), [NEt4]2 [W3OCl6(O2CCH3)3] is the first 9-electron compound of this type containing tungsten. It was prepared by reduction of [Et4N][W3OCl6(OAc)3] in benzene with Na/Hg. It crystallized in space groupP212121 with unit cell dimensionsa=11.076(2) Å,b=14.345(2) Å,c=21.026(3) Å,V=3574(1) Å3,Z=4. The anion resides on a general position but has virtual C3v
symmetry, with W-W distances of 2.577(1) Å, 2.612(1) Å, 2.584(1) Å and a mean value of 2.591[15] Å. 相似文献
994.
M. Heber Chr Liedtke H. Korte E. Hoffmann-Posorske A. Donella-Deana L. A. Pinna J. Perich E. Kitas R. B. Johns H. E. Meyer 《Chromatographia》1992,33(7-8):347-350
Summary Capillary electrophoresis is a novel technique in the non-radioactive determination of phosphoamino acids. The main advantage of the method presented is the high selectivity and the ability to separate all phosphoamino acid derivatives. Non-radioactive determination of PTH or dabsyl phosphoamino acids by capillary electrophoresis provides a fast and simple screening procedure for all O-phosphorylated amino acids in protein and peptides in the low picomolar range. 相似文献
995.
The new layered ternary compound Nb3GexTe6 (x ? 0.90) was prepared by direct combination of the elements taken in the stoichiometric proportions 3 : 1 : 6, heated at 1 000 °C for 10 days in silica tubes and quenched to room temperature. The phase crystallizes in the orthorhombic symmetry, space group Pnma (#62), with the following single crystal refined parameters: a = 643.18(5) pm, b = 1391.98(11)pm and c = 1 154.07(5) pm, with Z = 4. The structure was refined to an R of 3.4% (Rw = 4.6%), with 1969 independent reflexions and 49 parameters. The structure is based on the close stacking of trigonal prismatic (TP) slabs in the AA/BB mode. The slabs can be seen as built up from face sharing biprisms, which are filled either by one or by two niobium cations situated in the middle of the trigonal prisms. The germanium is located in the middle of the common face of two prisms, leading to a rather unusual anionic square coordination. The refinements showed that this latter cation does not fill completely its square site. No cation was found in the van der Waals gap between the slabs. The mean dGe? Te distance (276.5 pm) is in agreement with GeII cations, while some Te …? Te distances (from 333.84 to 361.65pm) are too short for anions in a simple contact. These bonding distances, already mentionned in some MTe2 compounds, are to be ascribed to charge transfer in the structure, with a partial oxidation state for the tellurium anions. Short Nb? Nb and Nb? Ge distances (292.0 and 281.3 pm, respectively) imply intercationic bonding within the slabs. 相似文献
996.
Ju Tao LIU Xiao Hong WANG Jing Fu LIU Faculty of Chemistry Northeast Normal University Changchun 《中国化学快报》2004,15(7):859-862
A novel vanadate decamer, involving all vanadium atoms present in +5 oxidation and one formhydroxamic acid dimer cation readical, has been synthesized. The single-crystal X-ray diffraction shows that the orange crystal is formed in the triclinic system, space group Pi, a = 8. 4960 (17), b = 10.447 (2), c = 11.299 (2) A, α= 68. 82 (3)°,β= 87.35 (3)°, γ = 66.97(3)°. V = 855. 3(3) A3, Z = 8, R1 = 0. 0857, wR2=0. 2551. X-ray crystallographic and packing in superlattice studies showed that the crystal structure was constructed by electrostatic attraction of O-H…O hydrogen bonds between formhydroxamic acid dimer cation and decavanadate polyanion. Formhydroxamic acid dimer is got through controlling the condition of the reaction using formhydroxamic acid. 相似文献
997.
Christophe Biot Jean Dessolin Isabelle Ricard 《Journal of organometallic chemistry》2004,689(25):4678-4682
Starting from triazacyclononane, easily accessible ferrocenic quinoline derivatives were synthesized. Their antiplasmodial properties were investigated against chloroquine sensitive (HB3) and chloroquine-resistant (Dd2) Plasmodium falciparum. One of them, 7-chloro-4-[4-(7-chloro-4-quinolyl)-7-ferrocenylmethyl-1,4,7- triazacyclononan-1-yl]quinoline (4) showed potent antimalarial activity in vitro against the chloroquine-resistant strain Dd2 and therefore revealed to be the most promising lead from the present work for new organometallic antimalarial agents. 相似文献
998.
The hydrothermal reaction of VOSO4, As2O3, CoC2O4·2H2O and 2,2-bipy yields a novel arsenic-vanadate [CoII(2,2-bpy)2]2[AsIII8VIV 14O42(H2O)]·H2O (1), which is characterized by IR, elemental analysis, TGA, magnetic susceptibility and single crystal X-ray diffraction analysis. X-ray diffraction shows that compound 1 is the first example of tubular arsenic–vanadium cluster containing infinite {[Co(2,2-bpy)2]2[As8V14O42(H2O)]} chain constructed from [As8V14O42(H2O)] clusters interconnected through [Co(2,2-bpy)]2+ units. Crystal data: 1, orthorhombic, P 212121, a=12.1401(2) Å, b=15.8722(1) Å, c=39.9533(5) Å, Z=4.Graphical Abstract: A novel polyoxoarsenicvanadate, [CoII(2,2-bipy)2]2 [AsIII8VIV 14O42(H2O)]·H2O, is depicted along with a tubular hybrid solid with a rhombic tube formed within the chain. 相似文献
999.
Qiang Li Pingfan Wu Yongge Wei Hongyou Guo 《Journal of organometallic chemistry》2006,691(6):1223-1228
An organic-inorganic hybrid compound, (Bu4N)2[Mo6O18(NAr)] (Ar = p-BrC6H4) has been synthesized via the DCC dehydrating protocol of the reaction of [α-Mo8O26]4− with 4-bromoaniline hydrochloride in anhydrous acetonitrile, which has been characterized by UV-Vis spectra, 1H NMR and single crystal X-ray diffraction study. By comparing the UV-Vis spectra, which were used to monitor the reaction, the optimum preparative condition for this compound was also determined. This compound crystallizes in the monoclinic space group P21/n, which is featured in a terminal para-bromophenylimido group linked to an Mo atom of a hexamolybdate cluster by a Mo-N triply bond. In addition, there are π-π dimerization of the neighboring cluster anions though the parallel aromatic rings in their crystals. 相似文献
1000.
Summary The essential oils of Estonian spruce and pine needles have been analysed by a combination of steam distillation/extraction, GC and GC-MS. According to their monoterpene composition Estonian pines belong to a high carene chemotype with monoterpenes representing up to 85% of total oil. Estonian spruce needle oil contains up to 70% of oxygenated terpenes and more limonene and 1,8-cineole than the same spruce species [Picea abies (L.) Karst.] from other localities.A total of 60 components were identified. Coefficients of variation describe the range of component contents in individual trees within the population. 相似文献