排序方式: 共有21条查询结果,搜索用时 343 毫秒
1.
Ahmad Al-Alousy Saad Alshehri John Burgess Maria del Mar Graciani Maria-Luisa Moya Ernestina Muñoz Amalia Rodriguez Francisco Sanchez 《Transition Metal Chemistry》1993,18(2):179-181
Summary Dependences of rate constants on pressure (up to 1 kbar) and on added salt concentration (up to 6.0 mol dm–3 LiNO3, NaNO3, NaCl, Na2SO4 or KNO3) have been established for dissociative substitution of pentacyanoferrates(II), [Fe(CN)5L]3– with L = 4-cyanopyridine, 4,4-bipyridyl, 4-phenylpyridine and 4-t-butylpyridine. Activation volumes derived directly from pressure effects, and indirectly from salt effects via surface tension dependences and derived surfaces of activation, are reported, compared and discussed. 相似文献
2.
Maria Luisa Moyá Antonio Barrios Maria del Mar Graciani Rafael Jiménez Ernestina Muñoz Francisco Sánchez John Burgess 《Transition Metal Chemistry》1991,16(2):165-168
Summary The kinetics of replacement of 4,4-bipyridine, (4,4-bipy), and 4-cyanopyridine, (4-CNpy), by cyanide in [Fe(CN)5-(4,4-bipy)]3-. at 298 K have been studied in binary aqueous mixtures containing different amounts of t-butanol, methanol, glycerol, ethyleneglycol and sucrose. The plots of logarithms of the limiting rate constantsversus the mole fraction of water are linear over the entire composition range studied, showing the importance of solvation phenomena. A different straight line of log (kL/s–1)versus XH2O is obtained for each mixture, indicating the influence of other solvent parameters on the reaction rate. A multiparameter regression of G
exp
with A (acidity vector), B (basicity vector) and GE is used for both reactions; plots of G
calc
versus G
exp
are linear with slopes of near unity. 相似文献
3.
Mariá Ernestina Chávez Rodríguez Angel López Gómez 《International Journal of Theoretical Physics》2001,40(1):95-104
The only pair of binary classical essential connectives for which the Artin braid relation holds is a distributive lattice, i.e. the Boolean disjunction and conjunction of 相似文献
4.
5.
6.
7.
8.
Claudia Villanueva‐Cañongo Nury Pérez‐Hernández Beatriz Hernández‐Carlos Ernestina Cedillo‐Portugal Pedro Joseph‐Nathan Eleuterio Burgueño‐Tapia 《Magnetic resonance in chemistry : MRC》2014,52(5):251-257
Chemical investigation of the aerial parts of Senecio polypodioides lead to the isolation of the new eudesmanoid 1β‐angeloyloxyeudesm‐7‐ene‐4β,9α‐diol ( 1 ) and the known dirhamnosyl flavonoid lespidin ( 3 ), while from roots, the known 7β‐angeloyloxy‐1‐methylene‐8α‐pyrrolizidine ( 5 ) and sarracine N‐oxide ( 6 ), as well as the new neosarracine N‐oxide ( 8 ), were obtained. The structure of 1 and 8 was elucidated by spectral means. Complete assignments of the 1H NMR data for 5 , 6 , sarracine ( 7 ), and 8 were made using one‐dimensional and two‐dimensional NMR experiments and by application of the iterative full spin analysis of the PERCH NMR software. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
9.
Amalia Rodríguez Carmen Carmona Ernestina Muñoz Francisco Sánchez John Burgess 《Transition Metal Chemistry》1991,16(5):535-541
Summary Different approaches to the interpretation of solvent effects on reactions between ionic reactants are analysed, taking as a basis the kinetic data corresponding to the sulphite-hexacyanoferrate(III) and peroxodisulphate-hexacyanoferrate(III) oxidations. It is concluded that the approach based on the use of solvent parameters is the more promising, although knowledge of the transfer chemical potentials of the reactants may also be useful in the interpretation of kinetic behaviour. 相似文献
10.
Rodríguez Amalia Muñoz Ernestina Sánchez Francisco Moya María Luisa Burgess John 《Transition Metal Chemistry》1992,17(1):5-8
Transition Metal Chemistry - The wavelengths of absorption maxima are reported for two ligand field bands of hexathiocyanatochromate(III), $ {? Cr(NCS)_{6}^{3-}} $, over a range of... 相似文献