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81.
Lanthanide p-toluene sulphonic acid (ptsa) complexes were prepared for La, Pr, Nd, Sm, Eu, Dy, Ho, Er and Yb, and found to exist as Ln(ptsa)3. Conductivity studies of La(ptsa)3 in DMSO and DMF suggest 1:2 and, possibly, 1:1 electrolyte behaviour in these solvents, respectively. NMR lanthanide-induced chemical shifts (LIS) for aromatic protons in (ptsa)? and methyl protons in DMSO, were measured for all complexes as a function of the [Ln3+[DMSO] in a medium consisting of CCl4, DMSO, and CH3CN. Analysis of the LIS data suggests a change in (ptsa)? coordination round Ln3+ across the lanthanide series. 相似文献
82.
83.
Stable α-cymantrenylcarbonium ions have been identified by solution IR spectroscopy. The substitution of tert-phosphine for CO markedly stabilises the carbonium ions. 相似文献
84.
85.
The behaviour of commercial, membrane-covered dissolved oxygen detectors is considerably more complicated than the orginal model of Mancy et al. would suggest. For example, the steady-state current is dependent both on the thickness and nature of the electrolyte behind the membrane. And transient currents obtained for switch-on of the detector are not completely described by the simple diffusional model. This paper examines these examples of more complicated behaviour. An analysis of the transient current for a step change in dissolved oxygen concentration is also given. 相似文献
86.
87.
Thomas T. Tidwell 《Tetrahedron letters》1979,20(48):4615-4618
Diethylketene and organometallic reagents form enolates capturable by methyl iodide or trimethylsilyl chloride with greater than 95% positional selectivity. 相似文献
88.
The rates and products of addition of benzeneselenenyl chloride to ethylene and its six Me substituted derivatives have been determined in methylene chloride at 25°. Unlike the addition of 4-chlorobenzenesulfenyl chloride to this same series of compounds, the effect of Me groups on the rates of addition is not cumulative. Also the regiochemistry of the product is different. For arenesulfenyl chloride additions, products of anti-Markownikoff orientation are formed preferentially under conditions of kinetic control. Under similar conditions regiospecific formation of the Markownikoff adduct is observed for the addition of benzeneselenenyl chloride to methylpropene and 2-methyl-2-butene. These data indicate a difference in both rate and product determining transition states between additions of arenesulfenyl and selenenyl chlorides to alkenes. 相似文献
89.
H.F. Chambers R.W. Kirk J.K. Thompson M.J. Warner P.M. Wilt 《Journal of Molecular Spectroscopy》1975,58(1):76-86
The infrared spectrum of HC13F3 is reported for the first time. Fundamental frequency shifts due to carbon-13 substitution have been measured and rotational analyses of several of the fundamental and combination bands are given. Coriolis x-y and Fermi perturbations are evident in several of the bands. Table VI summarizes the data obtained in this study. 相似文献
90.
The microwave spectrum of trimethylbromosilane (trimethylsilylbromide) has been investigated in the 26.5–40.0-GHz region. Spectra of several isotopic species have been observed, including the previously unreported spectrum of the 1H12C30Si81Br species, which yielded a B rotational constant of 1440.92 ± 0.02 MHz. From the experimental data it has been possible to derive the following structural parameters: SiBr = 2.235 ± 0.002 Å, SiC = 1.856 ± 0.010 Å, and ∠CSiBr = 107.5 ± 0.1°. The results have been compared to other relevant data and discussed in terms of prevailing chemical bonding principles. 相似文献