Please use this identifier to cite or link to this item:
|Type:||Artigo de periódico|
|Title:||Marked changes in relative nucleophilicity in comparing S(N)2Ar reactions of free arenes and coordinated arenes. Kinetic studies of reactions of (eta(6)-chlorobenzene)(eta(5)-cyclopentadienyl)iron(II) tetrafluoroborate with anionic and neutral nucleophiles|
|Abstract:||Quantitative kinetic studies have be en made of reactions of the (eta(6)-chlorobenzene)(eta(5)-cyclopentadienyl)iron(II) cation, (C6H5Cl)Fe(C5H5)(+) (1), With methoxide, phenoxide, methanethiolate, benzenethiolate, and azide ions in methanol, piperidine, morpholine, aniline, and thiourea in methanol, and guanidine in ethanol. The results were compared with the same nucleophile-solvent combinations in reactions with 1-chloro-2,4-dinitrobenzene, C6H3(NO2)(2)Cl (2). In general, the reactivity decreases on passing from 2 to 1. The decrease is small (less than or equal to 10(-1)) for phenoxide (PhO(-)), methanethiolate (MeS(-)), and guanidine (gua) and large (ca. 10(-5)) for benzenethiolate (PhS(-)), azide (N-3(-)), piperidine (pip), morpholine (morph), aniline (anil), and thiourea (thiou). The differences in reactivity when comparing the S(N)2Ar reactions of 1 and 2 is discussed in terms of the different location of the negative charge generated in the transition state by the electrons displaced from the reaction center by the entering groups (arenide electrons).|
|Editor:||Amer Chemical Soc|
|Appears in Collections:||Artigos e Materiais de Revistas Científicas - Unicamp|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.