310 research outputs found
English borrowings in the Spanish language: language policy of the Royal Academy of the Spanish language and the Fundéu BBVA regarding anglicisms
We can observe a rather purist attitude of certain Spanish institutions towards the use of anglicisms in the Spanish language.This difference in attitudes towards openness to other languages between the various countries may be explained by, among other things, the existence of linguistic institutions such as the Royal Academy of the Spanish Language (La Real Academia Española) and the Foundation of Urgent Spanish (Fundéu BBVA), which, according to many researchers, follow a restrictive policy against the use of anglicism
Organic chemistry. History and mutual relations of universities of Russia
© 2017, Pleiades Publishing, Ltd. The review describes the history of development of organic chemistry in higher schools of Russia over a period of 170 years, since the emergence of organic chemistry in our country till now
Modern Trends of Organic Chemistry in Russian Universities
© 2018, Pleiades Publishing, Ltd. This review is devoted to the scientific achievements of the departments of organic chemistry in higher schools of Russia within the past decade
Combined Experimental and Computational Studies on the Nature of Aromatic C−H Activation by Octahedral Ruthenium(II) Complexes: Evidence for σ-Bond Metathesis from Hammett Studies
Octahedral ruthenium complexes of the type TpRu(L)(NCMe)R [Tp = hydridotris(pyrazolyl)borate; R = alkyl or aryl; L = CO or PMe3] have been shown previously to initiate the C-H activation of aromatic substrates. In order to probe the nature of the C-H activation step, reaction rates have been theoretically obtained for the conversion of TpRu(L)(η2-C, C-C6H5X)Me to TpRu(L)(P-C6H4X) and CH4 where X is varied among Br, Cl, CN, F, H, NH2, NO 2, and OMe. A linear Hammett correlation is calculated with a positive p value of 2.6 for L = CO and 3.2 for L = PMe3. Calculated kinetic data for the aromatic C-H activations indicate that an electrophilic aromatic substitution mechanism is unlikely. While experiments cannot fully replicate the entire range of calculated Hammett plots, reactivity trends are consistent with the calculations that suggest activation barriers to overall metal-mediated arene C-H bond cleavage are reduced by the presence of electron-withdrawing groups in the position para to the site of activation. Previous mechanistic studies, as well as the structure and imaginary vibrational modes of the present transition states, validate that the C-H activation for this family of TpRu complexes occurs through a σ-bond metathesis-type pathway. © 2007 American Chemical Society
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