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241.
A spectrophotometric study on a direct picric acid reaction for creatinine in severely jaundiced serums is described. A problem appears to be caused by the oxidation of bilirubin which minimizes rising absorbance when using continuous measurement. Simple examples of interferences with the kinetic mode are shown along with the hitherto unreported interference of the drug, Cephalothin, which also undergoes a picric acid reaction. A procedure in which a delta absorbance is obtained after decolorization of the Jaffé complex by acidification is shown as one available means for obviating the bilirubin effect. However, the theory that Jaffé-reactive interferences do not decolorize with the same acid treatment is not totally applicable when the drug, Cephalothin, is present. 相似文献
242.
243.
Single crystals of U3+:LaBr3 were grown by the Bridgman-Stockbarger technique. High-resolution polarized absorption spectra of the crystals were recorded at 4.2 K in the 4000-50,000 cm−1 range. Sixty-four experimental crystal-field energy levels of the U3+ ion were fitted to a semiempirical Hamiltonian employing free-ion, one-electron crystal-field as well as two-particle correlation crystal-field (CCF) operators with an r.m.s. deviation of 28 cm−1. The performed analysis of the spectra enabled the determination of crystal-field parameters and assignment of the observed 5f3→5f3 transitions. The effects of selected CCF operators on the splitting of some specific U3+ multiplets have been investigated and the obtained values of Hamiltonian parameters are discussed and compared with those reported in previous analyses. 相似文献
244.
The metalation of allyl benzyl thioether involves the benzylic or the allylic hydrogens. The benzylic carbanion undergoes a rapid[2,3] sigmatropic shift whereas the allylic carbanion gives rise to various rearrangements, among them migration of the allylic unit to the para position with allylic inversion. The temperature dependence of the ratio of products arising from the benzylic carbanion vs those from the allylic carbanion shows that the allylic-to-benzylic carbanion transformation occurs only under special conditions: (a) with slow addition of the base; (b) with thioether in excess relative to the base, and (c) on raising the temperature of the reaction medium from ?78° to ?15°. In the last instance, the proton transfer is intramolecular as shown with labeled thioethers. The extent of the different rearrangements depends on the temperature and solvent. A choice of mechanism cannot be made at this time for the para migration 5→9a. A leaving group effect on the reaction regioselectivity of the carbanion from allyl methyl thioether with benzyl halides has been noticed. The presence of dibenzyl indicates that, in addition to SN2 reactions, some electron transfer process is occurring. 相似文献
245.
John A. Bishop 《Analytica chimica acta》1973,63(2):305-311
Four different methods for the calculation of the formation constants of fluorescing complexes are discussed. The methods were used to determine constants for the complexes of aluminum(III), gallium(III) and indium(III) with 8-quinolinol-5-sulfonate anion. 相似文献
246.
Lemi Türker 《Journal of Molecular Structure》2004,680(1-3):47-51
Semiempirical quantum chemical calculations at the level of AM1 (restricted Hartree–Fock) have been performed on a fullerene derivative, C54N4, theoretically obtained from C60 and its mono and diprotonated forms. All these structures are stable, but endothermic in nature. Some calculated geometrical and physicochemical properties of these have also been reported. 相似文献
247.
Jolanta Olkowska‐Oetzel Dieter Fenske Petra Scheer Andreas Eichhfer 《无机化学与普通化学杂志》2003,629(3):415-420
Syntheses and Thermal Properties of Cluster Molecules, formed from Groups 11‐13‐16 Elements In the presence of PPh3, CuX (X = Cl, CH3COO) or AgOC(O)C6H5 and GaCl3 react in THF with S(SiMe3)2 or Se(SiMe3)2 to yield [Cu6Ga8Cl4S13(PPh3)6] ( 1 ), [Cu6Ga8Cl4Se13(PPh3)6] ( 2 ), [Ag6Ga8Cl4S13(PPh3)6] ( 4 ) and [Ag6Ga8Cl4Se13(PPh3)6] ( 5 ). The use of PnPr2Ph instead of PPh3 and subsequent layering with n‐hexane leads to the formation of the cluster [Cu6Ga8Cl4Se13(PnPr2Ph)12] ( 3a , 3b ). Reaction of CuCl, GaCl3 and PnPr3 with Se(SiMe3)2 in THF results in the crystallisation of the ionic cluster (HPnPr3)2[Cu2Ga4Cl4Se6(PnPr3)4] ( 6 ). The structures of 1 — 6 were determined by X‐ray single crystal structure analysis. Thermogravimetric measurements of the cluster molecules and powder diffraction patterns of the remaining powders reveal the potential use of them as single source precursor compounds for the synthesis of the related ternary solid state materials. 相似文献
248.
By using a micro-bomb calorimeter, the standard enthalpies of combustion of C60 and C70 have been determined to be - (25 947.1±8.5) and - (29 956.1 ± 8.9) kJ/mol respectively. A g. 1. c. analysis indicated that
the amounts of residual organic solvents in the samples were very small, and their effects on the final results were negligible.
The energy of combustion ofC60 determined in this work is in agreement in the uncertainty interval with that determined by means of traditional calorimeter
using macro amount of sample. The enthalpies of formation of these two substances have been derived. The strain energies in
the molecules of C60 and C70 were estimated by a bond energy scheme and by using corannulene as the model compound, the results estimated from different
methods are very close.
Project supported by the National Natural Science Foundation of China (Grant No. 29473143) 相似文献
249.
The intermolecular potential function of Smith–Thakkar type for C60 has been proposed, and its expression is as followsThe unit of u(r) is J/mol, r is the distance between two C60 molecules center and the unit is nm. Some properties of C60 in the gas and crystal have been studied using the interaction potential of Smith–Thakkar type, such as stability of C60 crystals, virial coefficient and lattice dynamics. 相似文献
250.
E.?BertoloEmail author J.?A.?Kilner M.?Sahibzada 《Journal of Solid State Electrochemistry》2004,8(9):585-591
18O/16O isotope exchange depth profiling (IEDP) combined with secondary ion mass spectrometry (SIMS) has been used to measure the oxygen tracer diffusivity of SrCe0.95Yb0.05O3– between 800 °C and 500 °C at a nominal pressure of 200 mbar. The values of D* (oxygen tracer diffusion coefficient) and k (surface exchange coefficient) increase steadily with increasing temperature, and the activation energies are 1.13 eV and 0.96 eV, respectively. Oxygen ion conductivities have been calculated using the Nernst–Einstein equation. The transport number for oxide ions at 769 °C, the highest temperature studied, is only ~0.05. Moreover, SrCe0.95Yb0.05O3– has been studied using impedance spectroscopy under dry O2, wet O2 and wet H2 (N2/10% H2) atmospheres, over the range 850–300 °C. Above ~550 °C, SrCe0.95Yb0.05O3– shows higher conductivity in dry O2 than in wet O2 or wet H2; below that temperature the results obtained for the three atmospheres are comparable. Dry O2 shows the highest activation energy (0.77 eV); the activation energies for wet O2 and wet H2 are identical (0.62 eV).Abbreviations HTPC high-temperature proton conductor - IEDP isotope exchange depth profiling - SIMS secondary ion mass spectrometryPresented at the OSSEP Workshop Ionic and Mixed Conductors: Methods and Processes, Aveiro, Portugal, 10–12 April 2003 相似文献