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91.
Hong-Ling Li Koichi Takahashi Yusuke Ujihira Mariko Ishiwatari Kurima Kobayashi Takahiko Iriyama Tokuzo Konishi 《Journal of Thermal Analysis and Calorimetry》1995,45(6):1359-1371
The Mössbauer spectra of Sm2Fe17Nx, prepared by the nitrogenation of Sm2Fe17 powders in an ammonia and hydrogen atmosphere, were observed at elevated temperatures to shed light on the thermal behavior of nitrogen in the compounds Sm2Fe17Nx. It was found that there were large differences in thermal behavior between the starting Sm2Fe17, crystalline Sm2Fe17Nx (x≈1.7) and amorphous Sm2Fe17Nx(x~7). The thermal decomposition behavior of Sm2Fe17N3.2, developed as one of the most promising hard magnetic materials, was found to be different under different atmospheres. 相似文献
92.
芳香二磺酸的配位化学研究化合物[Ni(cyclam)(1,5nds)]·1/3H_2O(1)和[Co(cyclam)(H_2O)_2](1,5nds)·2H_2O(2)的合成与结构(英文) 下载免费PDF全文
合成了两个二价的过渡金属磺酸化合物,并通过X-射线衍射单晶结构分析进行结构表征。化合物犤Ni(cyclam)(1,5nds)犦·1/3H2O(1)以P2(1)/c空间群结晶,晶胞参数为a=8.583(5),b=10.533(6),c=12.946(7)?,β=92.433(9)°。犤Ni(cyclam)犦2+与两个磺酸基团形成弱配位,从而构筑了一维的配聚物。犤Ni(cyclam)犦2+与磺酸基团之间的作用还通过O2S-O…H-N型氢键进一步被加强。化合物犤Co(cyclam)(H2O)2犦(1,5nds)·2H2O(2)以P1珔空间群结晶,晶胞参数为a=8.738(5),b=9.324(5),c=10.118(5)?,α=81.382(8),β=64.868(8),γ=62.999(8)°。在该化合物中,磺酸基团没有与Co2+形成配位键,而是以平衡离子的形式存在并与配离子形成氢键,构筑了有序的三维结构。 相似文献
93.
Ahmed R. Hassan Khadiga F. Amer Sayed A. El-Toumy John Nielsen 《Natural product research》2019,33(8):1135-1139
Isolation of flavonoids from the aerial parts of Taverniera aegyptiaca Bioss. (Fabaceae) led to identification of one new flavonol glycoside, isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (1), along with eleven compounds, which previously have not been isolated from this plant quercetin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (2), isorhamnetin-3-O-α-l-arabinopyranoside (3), quercetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (4), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (7), isorhamnetin 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (8), isorhamnetin 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside] (9), kaempferol 3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside] (10), isorhamnetin (11), 4,4′-dihydroxy-2′-methoxychalcone (12), formononetin (13) and calycosin (15)] and some compounds already known from this plant [quercetin-3-O-robinobioside (5), isorhamnetin-3-O-robinobioside (6), afrormosin (14) and odoratin (16)]. 相似文献
94.
铜(Ⅱ)-三氮唑偶氮络合物与脱氧核糖核酸相互作用的电化学行为 总被引:5,自引:0,他引:5
运用电化学方法研究了铜(Ⅱ)-三氮唑偶氮(2-[2,3,5-三氮唑偶氮]-5-二甲氨基苯甲酸,TZAMB)络合物与脱氧核糖核酸(DAN)的相互作用。在pH2.5(0.05mol/L)邻苯二甲酸氢钾(PBS)缓冲溶液中,DNA与Cu(Ⅱ)-TZAMB络合物形成一种电惰性结合物,使Cu(Ⅱ)-TZAMB络合物的还原峰电流减小。通过循环伏安法、盐效应以及紫外-可见吸收谱证实了是由Cu(Ⅱ)-TZAMB络合物与DNA形成一种插入式的电惰性结合物而使其峰电流下降。根据这种峰电流下降可以测定DNA,测定结果令人满意。 相似文献
95.
The crystal structures of a pair isomers of [Co(3,3-tri)(amp)Cl][ZnCl4] (here 3,3-tri = N-(3-Aminoprop- yl)-1,3-propanediamine; amp=2-(Aminomethyl)pyridine) have been determined by single crystal X-ray diffrac-tion. They are the epimers with the only difference of the orientation of the Sec-NH proton in 3,3-tri ligand. The crystals with the anti-epimer (m1[ZnCl4]·CH3OH·H2O) are monoclinic, space group C2/c with eight molecules in a unit cell of dimensions a=30.401(5)?,b=8.0469(13)?,c=18.817(3)?,β=93.346(3)°,V=4595.3(12)?3,Dc=1.708g·cm-3,Z=8,F000=2416,R=0.0462,Rw=0.1304. The crystals of the syn-epimer (m2[ZnCl4]·H2O) are triclinic, space group P1 with two molecules in a unit cell of dimensions a=8.9752(12)?,b=9.8855(12)?,c=12.6886(16)?,α=89.228(3)°,β=76.447(2)°,γ=80.428(3)°,V=1078.8(2)nm3,Dc=1.721g·cm-3,Z=2,F000=568,R=0.0313,Rw=0.0929. The crystal parameters, such as bond lengths and angles, are well consistent with the data of an ab initio computational result (RHF/LANL2DZ opti-mised structure). The average error for bond length is about 1.6%, only two of them in the isomer m3 (Co-N2 and Co-N4) are over 3%, (3.09% and 4.28% respectively). The errormax for bond angle is 2.52%, the bond angles with an over 2% error are only 3.6% out of all bond angles. 相似文献
96.
Different molar reactions of Fe(OPr1)3, and FeCl3 with benzothiazolines having an NSH donor system. derived by the condensation ofo-aminothiophenol with heterocyclic aldehydes. viz. pyridine-2-aldehyde. furfuraldehyde and thiophene-2-aldehyde. lead to the
formation of [Fe.Pr1(NS)2]2, [Fc(NS)3] and [Fe(NS)2Cl| type of complexes. The resulting derivatives have been characterized by elemental analysis, conductivity measurements,
molecular weight determinations and magnetic studies. IR, electronic, M?ssbauer and ESR spectral data have been used to deduce
the structures of the resulting derivatives. 相似文献
97.
0IntroductionRecently,thecompoundscontaining1H-1,2,4-tr-iazolegrouphaveattractedmuchinterestbecauseoftheirexhibitingsomefungicidalactivityandplantgrowthregulatingactivity犤1犦,andshowingantibacterialactivityagainstPucciniareconditeandrootsgrowthregulationforcucumber犤2犦.Also,suchcompoundsareincreasinglybeingstudiedbecauseofthecoordinationchemistryofazolesactingasligandsintransitionmetalcompounds.Asamatteroffact,thetriazolederivativeshavebeenextensivelyusedasterminalandbridgingligands,andthey… 相似文献
98.
Aki H. Niiya T. Iwase Y. Goto M. Kimura T. 《Journal of Thermal Analysis and Calorimetry》2004,77(2):423-435
The formation of inclusion complexes between amoxicillin (AMPC) and 2-hydroxypropyl-β-cyclodextrin (HPCD) was investigated
by isothermal microcalorimetry and molecular dynamics simulation to evaluate the inhibitory effects on the degradation of
AMPC in aqueous solutions at various pH. The process depended significantly on the ionic species of AMPC in the solution.
In a strong acid solution, cationic AMPC and HPCD formed two different types of inclusion complexes with a 1:1 stoichiometry:
the first-type had a high association constant K
1 of 4.0-8.0·103 M-1 and included the penam ring of AMPC in the HPCD cavity (Mode I), while the second-type with a K
2 of 1.0·103 M-1 contained the phenyl group of AMPC (Mode II). Furthermore, a complex with a 1:2 (AMPC:HPCD) stoichiometry was realized in
a two-step reaction and was characterized by a smaller K
1:2of 4.0·102 M-1 and larger negative enthalpy and entropy changes than the complexes with a 1:1 stoichiometry. Since the β-lactam ring of
AMPC could be protected by inclusion with HPCD in the 1:2 complex and Mode I of 1:1 complexes, the degradation of AMPC in
the presence of HPCD was approximately four times slower than in its absence at pH 1.2 and 37°C. In weak acid and neutral
solutions, zwitterionic AMPC and HPCD formed only one type of inclusion complex with a 1:1 stoichiometry, where the phenyl
group was included (Mode II). AMPC was very stable in these solutions (t
1/2=226 h at pH=6.0) and there is little significant difference in the degradation rate between complexed AMPC and uncomplexed
AMPC. Thus, the results indicated that the inclusion complex of AMPC with HPCD, effectively increasing the stability of AMPC
in a strong acidic solution like that the stomach, would be useful for eradicating Helicobacter pylori infection and as a drug delivery system.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
99.
The molecular structure and absorption spectra of monothio- and dithio-naphthalimides were compared to their naphthalimide analogues using AM1, PM3 and ZINDO/S semiempirical quantum chemical methods. The substitution of the 4R-naphthalimide oxygen atoms by sulphur atoms resulted in a red-shift of the absorption spectra by Δλmax60-65 and 100-140 nm, respectively. The thionated naphthalimide derivatives do not show observable fluorescence due to intersystem crossing to the triplet -states localised at the CS groups. The -absorption bands of monothioimides are located at 525-580 nm (ε=60-80) and those for dithioimides at 535-560 nm (ε=140-390) and 628-686 nm (ε=34-68). None of these transitions are solvent sensitive. The -transitions of N-phenylthioimides have also a small contribution from -states due to a partial conjugation between CS group and π-electronic system of the N-phenyl ring. As a result, the bands of aromatic substituted N-phenylthioimides are red-shifted as compared to those of the aliphatic N-methyl-thioimides. 相似文献
100.
A boundS
l is given for the number of bound statesn
i in thelth partial wave corresponding to a spherically symmetric potential in non-relativistic quantum mechanics. This bound is given
by
whereV
a(l, r) is the attractive part of the effective potentialV(r)+l(l+1)/r
2. Extensive comparative study ofS
i and the Bargmann inequality is made. 相似文献