共查询到20条相似文献,搜索用时 15 毫秒
1.
NMR SPDE measurements are reported for the lamellar (dispersions and multibilayer stacks) and hexagonal phases of sodium octanoate/octanol/D2O mixtures. In the lamellar Lβ and Lγ (gel) phases the octyl chains are rigid and perfectly ordered, while in the lamellar Lα and hexagonal phases they are flexible and disordered. In particular, the measurements show that in the fluid lamellar Lα phase, there is a marked discontinuity in the octyl chain flexibility at the C5-C6 segment; this behaviour is identical to that previously reported for the alkyl end-chains in smectic 4,4′-di-n-octyloxyazoxybenzene. In contrast, in the hexagonal phase, there is an effectively continuous flexibility gradient along the whole length of the octyl chain as in nematic 4,4′-di-n-octyloxyazoxybenzene. The behaviour in the lamellar phase is attributed to interference between cooperative conformational modes and localized random thermal fluctuations. 相似文献
2.
Acetylergosterol(tricarbonyl)iron has been prepared in good yield using benzylideneacetone(tricarbonyl)iron. The steroidal complex may be hydroborated or subject to osmolysis, to yield potential vitamin D precursors. 相似文献
3.
S. Zecevic B. Simic-Glavaski E. Yeager A.B.P. Lever P.C. Minor 《Journal of Electroanalytical Chemistry》1985,196(2):339-358
Cyclic voltammetric measurements of adsorbed Fe- and Co-tetrasulfonated phthalocyanine (TsPc) and Co-phthalocyanine (Pc) have been carried out on ordinary pyrolytic graphite and silver electrodes at different solution pH ranging from 1 to 13. Many voltammetric peaks were found to be pH dependent with a slope of ?59 mV/ unit pH. In some instances this dependence was observed in alkaline or acid solutions only. The influence of oxygen has been also examined. 相似文献
4.
Philip G. Harrison Robin C. Philips John A. Richards 《Journal of organometallic chemistry》1976,114(1):47-52
An X-ray diffraction study of (2,6-dimenthylphenyl)dicyclopentadienyl-titanium has shown the two slightly staggered cyclopentadienyl ligands to be π-bonded to the titanium atom (average distance TiC 2.35 Å); the ring planes include an angle of 41.6°. The aryl ligand is σ-bonded to the titanium atom (TiC distance 2.18 Å). The short distance (2.55 Å) between Ti and one of the methyl hydrogen atoms suggests an interaction between the two atoms. 相似文献
5.
Chronopotentiometric studies of the tetrabutylammonium ion transfer from water to 1,2-dichloroethane
Electrochemically reduced graphite in contact with tetralkylammonium ions/DMF may react with electrophiles either as a nucleophile or as a reducing reagent. The reaction at the interface or at the immediately accessible active centres of the crystal causes some modification of the structure, which is studied here. This method allows the formation of polybutylated or poly-carboxylated graphite and may lead to other modified crystals of great interest for building modified electrodes. 相似文献
6.
The ESCA characterization of three similar new amorphous addition complexes of tin dichloride with tetradentate aromatic Schiff bases has been carried out. The results support the previously proposed ionic structure. 相似文献
7.
Oxygen is shown to adsorb molecularly on gold as well as on Ag and Pt. UV and X-ray photoelectron spectroscopy and Auger electron spectroscopy have been employed to investigate electron states of molecularly adsorbed oxygen. 相似文献
8.
9.
ESCA Sn 3d linewidths of nonconducting organometallic tin solids, prepared by in situ evaporation, are within about 10% of the values for analogous gas phase measurements. The similar line shapes (≈ 35% gaussian, 65% lorentzian) observed for solid state and gas phase spectra show that effects which give increasing gaussian components, such as charge broadening and phonon broadening, are very small in our solid state spectra. The general correlation between ESCA Sn 3d linewidths and Mössbauer quadrupole splittings indicates that electric field gradient splitting of the Sn 3d lines approaches ≈ 0.4 eV. 相似文献
10.
11.
12.
Cobalt ions in aqueous thiocyanate solution react with Aliquat-336-xylene solution to form anion-association complex which is easily extracted into the organic phase. A typical extraction procedure involves extracting a solution which is 10 ppm in cobalt and 0.06 M,
5. Stripping of Cobalt from 2% Aliquat-336-Xylene Solutions
Strippant | Cobalt stripped (%) |
Na2S (M) 1.0 | 18.3 |
2.0 | 10.7 |
Na2SO3 (M) 0.1 | 10.7 |
0.5 | 49.6 |
1.0 | 52.9 |
EDA (%) 2.5 | 76.6 |
NaOH (M) 0.1 | 4.1 |
0.5 | 74.1 |
1.0 | 90.8 |
2.0 | 76.8 |
NH4OH (M) 0.1 | 24.1 |
0.5 | 91.8 |
1.0 | 97.5 |
2.0 | 99.9 |
EDTA (M) 0.02 | >99.9 |
0.05 | >99.9 |
0.1 | >99.9 |
EDTA (%) 0.1 | >99.9 |
0.5 | >99.9 |
1.0 | >99.9 |