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1.
R. E. Gayoso M. A. Barral S. J. Nassiff 《Journal of Radioanalytical and Nuclear Chemistry》1997,215(2):223-227
The (EC, +) decay of168Hf, produced by the156Gd (16O,4n) reaction, has been studied, with high efficiency HPGe coaxial detectors, using on-line measurements with the RACHEL setup. Off-line measurements were also carried out using catcher collection technique. Energies and intensities of 119 -lines are reported among these only two were known in the earlier study ofChu andReednick. The168Lu level scheme built on the basis of single - and X-spectra and - coincidence measurements, allows the interpretation of 79 -transitions, between 38 excited states reported for the first time. 相似文献
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Eu(α NMA) 3(α HNMA)Phen (NMA =萘甲酸根 ;HNMA =萘甲酸 ;Phen =1,10 邻菲咯啉 )配合物晶体属三斜晶系 ,P1- 空间群 ,晶胞参数a =1.2 40 1( 3)nm ,b =1.30 5 6( 3)nm ,c =1.65 0 0 ( 3)nm ,α =73.0 1( 3)° ,β =82 .44( 3)° ,γ =62 .0 7( 3)° ,V =2 2 5 72 ( 8)nm3,Z =2 ,Dc=1.496g/cm3,F( 0 0 0 ) =10 2 6,R =0 .0 5 17.该配合物是双核分子 ,两个Eu(Ⅲ )离子通过 4个α 萘甲酸根的羧基桥联 .中心离子分别与五个羧基桥氧原子、一个螯合配位羧基的 2个氧原子和一个邻菲咯啉的 2个N原子配位 ,形成九配位的扭曲三帽三棱柱体 .双核分子中萘环与邻菲咯啉平面之间存在着π π相互作用 ,有利于该配位构型的稳定 .荧光光谱测定结果显示 ,标题配合物发光性能良好 相似文献
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Eu(α-NMA)_3(α-HNMA)Phen的晶体结构及光谱研究 总被引:2,自引:0,他引:2
Eu(α-NMLA)_3(α-HNMA)Phen(NMA=萘甲酸根;HNMA=萘甲酸;Phen=群, 晶胞参数α=l.2401(3)nm,b=1.3056(3)nm,C=1.6500(3)nm,α=2. 2572(8)nm~3,Z=2,D_c=l .496g/cm,F(000)=1026,R=0.0517.该配合物 是双酸根的竣基桥联.中心离子分别与五个竣基桥氧原子、一个鳌合配位梭基的2 个氧原子和一个邻菲咯啉的2个N原子配位,形成九配位的扭曲三帽三棱柱体,双核 分子中萘环与邻菲咯啉平面之间存在着π-π相互作用,有利于该配位构型的稳光 光谱测定结果显示,标题配合物发光性能良好. 相似文献
7.
Nikos G. Tsierkezos 《Journal of solution chemistry》2008,37(10):1437-1448
The cyclic voltametric technique utilizing a platinum working electrode was applied for the investigation of the electrochemical
oxidation of bis(benzene)chromium(0), (C6H6)2Cr to bis(benzene)chromium(I), (C6H6)2Cr+ in diethyl ketone (DEK), N,N-dimethylformamide (DMF), and DEK/DMF binary mixtures containing n-tetrabutylammonium hexafluorophosphate (TBAPF6) as the supporting electrolyte at T=298.15 K. The half-wave potentials (E
1/2) of the (C6H6)2Cr+/0 redox couple in DEK, DMF and DEK/DMF binary mixtures, were determined. The variation of E
1/2 with the solvent composition was found to be almost linear. The E
1/2 results were analyzed in terms of the electron-donating power of the solvent medium. The diffusion coefficients, D, were calculated using the Randles-Sevcik equation. The kinetics of the electrode reaction were investigated through the
determination of the heterogeneous electron-transfer rate constants, k
s, according to the electrochemical rate equation proposed by Nicholson. Furthermore, the activation Gibbs energies for the
electron-transfer process (ΔG
≠) were also calculated. The results indicate that the redox couple (C6H6)2Cr+/0 exhibits an electrochemically reversible and diffusion-controlled process in all the investigated solvent media. 相似文献
8.
Maria Lalia-Kantouri Christos D. Papadopoulos Antonios G. Hatzidimitriou Stavroula Skoulika 《Structural chemistry》2009,20(2):177-184
The reaction of Fe(III) with the substituted salicylaldehydes [X-saloH, where X = 3-OCH3 (L 1 ), 5-CH3 (L 2 ), 5-Cl (L 3 ), 5-NO2 (L 4 )] led to the formation of four new iron(III) hetero-heptanuclear complexes (Fe–Na) under the general formula [Fe2(X-salo)8Νa5] · 3OH · zH2Ο. The two different coordination modes of the ligand, as well as the geometry around the metal ions were deduced by X-ray structure analysis of compound 1, [Fe2(3-OCH3-salo)8Νa5] · 3OH · 8H2Ο. The complexes have also been characterized by physicochemical and spectroscopic (IR, UV–Vis, Mössbauer) methods. 相似文献
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The reaction of 3,3,5,5-tetramethyl-4,4-dibutyldipyrrolylmethene (HL) with cobalt(II) valinate (CoVal2) in DMF was studied by spectrophotometric method of molar ratios. The formation of a mixed-ligand complex CoValL was established and its electronic absorption spectrum was measured. The thermodynamic constant of complexation was calculated.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 177–178.Original Russian Text Copyright © 2005 by Guseva, Antina.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date. 相似文献
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M. J. Ozafran H. O. Mosca M. E. Vazquez W. R. Frosch S. J. Nassiff 《Journal of Radioanalytical and Nuclear Chemistry》1993,172(1):155-165
Excitation functions and isomeric ratios for184Re, from -induced reactions on181Ta and natural W have been measured using the stacked-foil method. The data are compared with the theoretical predictions provided by the equilibrium and pre-equilibrium reaction model; for this propose we used the code INDEX development by ERNST. 相似文献
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《结构化学》1993,(2)
<正> Gypenosides, a series of dammarane-type saponins from Gynostemma pentaphyllum Makino, were hydrolyzed under 5% H_2SO_4 catalysis to afford the title compound as a new secondary sapogenin in addition to panaxadiol and 2a-hydroxypanaxadiol. The crystals of the title compound were obtained from methanol solution and a colourless crystal with dimensions of 0.2 × 0.2 × 0.2 mm was used. C_(30)H_(50)O_3 相似文献
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M. J. Ozafran A. Archenti M. E. Vazquez S. J. Nassiff 《Journal of Radioanalytical and Nuclear Chemistry》1992,162(1):145-153
A stack of natural samarium was bombarded with 87 MeV -particles. Cumulative cross sections for the production of145Eu,146Eu,147Eu,148Eu,150Eu,152Eu and154Eu have been studied using gamma-ray spectroscopy. The data are compared with the theoretical results provided by equilibrium and pre-equilibrium reaction models, for this purpose we used the code ALICE of Blann. 相似文献
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An ecdysteroid analog has been synthesized from -sitosterol.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', 220141, Belarus', Minsk, ul. Akad. Kuprevich, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 488–491, July–August, 1999. 相似文献
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K. M. Turdybekov S. V. Lindeman T. V. Timofeeva Yu. T. Struchkov 《Chemistry of Natural Compounds》1991,27(2):169-173
A calculation has been made by the method of molecular mechanics, using the MM2 program, of a number of stereomeres of 1,5,6,7(H)- and 1,5,6,7(H)-guai-11(13)-en-6,12-olides. The possibilities of the adoption by the seven-membered ring of particular conformations according to the type of its linkage with the 5-membered carbocycle have been considered. Questions of the influence of the orientation of the Me groups on the degree of distortion of the conformation of the seven-membered ring from the ideal and the relative stabilities of the various conformers are discussed.A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 198–203, March–April, 1991. 相似文献
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利用小分子meso-四(α,α,α,α-O-苯乙酰苯)卟啉作为全抗原免疫小鼠,通过细胞融合等技术制备了单克隆抗体(McAb)1F2,利用高效液相色谱(HPLC)、基质辅助激光解吸飞行时间质谱(MALDI/TOFMS)证明纯化得到的单抗是很纯的.McAb1F2的保留时间是2.63 min,亚型为IgG2a,相对分子量为156 678.8.McAb 1F2-卟啉复合物形成时,卟啉Soret带最大吸收峰从408nm红移到416nm,并有增色效应,说明McAb1F2-卟啉是刚性且紧密结合.抗体酶稳定性很高,但比活力只有4.687 5 U/mg,为天然酶HRP的1.899%.抗体酶的Km=20.29 mmol/L,kcat=396.82 min-1,kcat/Km=1.955 7×104L·mol-1·min-1. 相似文献
16.
Jiangbo She Chao Gao Kai Cui Chaoqi Hou Wei Zhao Wei Wei Bo Peng 《Structural chemistry》2008,19(6):905-910
A novel neodymium pentafluoropropionate binuclear complex, Nd(C2F5COO)3 · Phen (Phen: 1,10-phenanthroline), was synthesized and characterized by single-crystal X-ray diffraction, elemental analysis,
FT-IR spectra, UV–Vis–NIR absorption, and PL spectra. Single-crystal data show that the complex bears centrosymmetric dinuclear
structure with a planar ligand configuration. Four carboxylato groups act as η2-chelate-μ2-carboxylato-k1O:k1O′-bridge-ligands, the other two occupy the terminal position as monodentate ligands. At the same time, the C–O distances
appear averaged which indicate the three atoms of carboxylato forming electron-conjugate system. Hydrogen bond and π–π-stacking
link the binuclear to two-dimensional sheet. Optical spectra exhibit the complex possesses typical Nd(III) ion absorption
and photoluminescence emission. 相似文献
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《Tetrahedron: Asymmetry》2001,12(1):89-94
Synthesis of key intermediates leading to 2-iso-oxacephems was carried out starting from l- and d-threonine. As predicted in our previous paper (Tetrahedron Lett. 1995, 36, 8303–8306) all diastereomers of 2-iso-oxacephems can be prepared from the appropriate enantiomers of the amino acid threonine. The absolute configuration of the 2,3- and α-carbon atoms in the β-lactam structure was determined by X-ray crystallographic studies. 相似文献
18.
Abstract-Compound 1, the carbocyclic analogue of Ara-T, was synthesized by a four-step synthesis from (+)-(lα,2α,3β,5β)-3-amino-5-(hydroxymethyl)-l,2,-cyclopemane-diol (2), which was prepared from cyclopentadiene via a eight-step route as a potential antiviral agent. 相似文献
19.
Kabbour H Coillot D Colmont M Masquelier C Mentré O 《Journal of the American Chemical Society》2011,133(31):11900-11903
The structure of the fully ordered α-Na(3)Ti(2)(PO(4))(3) NASICON compound was elucidated using high-quality single-crystal data. The cation/vacancy distribution forms a homogeneous 3D arrangement and could represent the absolute cationic ordering available in the full Na(3)M(2)(PO(4))(3) series, as verified for M = Fe. For M = Ti, the reversible α → γ transition was observed at 85 °C, leading to the standard disordered R ?3c γ model. Through JPDF analysis, the most probable Na(+) zigzag M(2)-M(1) diffusion scheme was directly deduced using our accurate crystallographic data. 相似文献
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Stereoisomers of 1,5,6,7(H)- and 1,5,6,7(H)-guai-11(13)-en-6,12-olides are calculated using molecular mechanics. The possibility of forming various conformations in the 7-membered ring is examined as a function of the fusion to the 5-membered C-ring. The effect of the methyl orientation on the conformation of the 7-membered ring and the relative stability of the conformers are discussed.Insitute of Phytochemistry, Karaganda, fax (3212)-43-37-73. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 54–56, January–February, 2000. 相似文献