Electrophilic Reactivity of Tetrabromorhodamine 123 is Bromine Induced: Convergent Interpretation through Complementary Molecular Descriptors

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• 作者：Jos茅 A. B. Ferreira ; Antonio S谩nchez-Coronilla ; Denisio M. Togashi ; Humberto Ferreira ; Jos茅 R. Ascenso ; S铆lvia M. B. Costa
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：December 6, 2012
• 年：2012
• 卷：116
• 期：48
• 页码：11938-11945
• 全文大小：382K
• 年卷期：v.116,no.48(December 6, 2012)
• ISSN：1520-5215

文摘

Nucleophilic addition of water and of methanol to 3,6-diamino-2,4,5,7-tetrabromo-9-[2-(methoxycarbonyl) phenyl]-9H-xanthen-9-ylium, 4BrR123, yields respectively 2-(3,6-diamino-2,4,5,7-tetrabromo-9-hydroxy-9H-xanthen-9-yl)xanthyl benzoate, HO4BrR123 and 2-(3,6-diamino-2,4,5,7-tetrabromo-9-methoxy-9H-xanthen-9-yl)xanthyl benzoate, MeO4BrR123. The novel experimental results are addressed theoretically. The linear free energy relationship, LFER, second-order perturbation theory analysis of the natural bond orbital, NBO, and quantum theory of atoms in molecules, QTAIM, lead to the same conclusion: the electron-withdrawing effect of bonded Br atoms in 4BrR123 extremely enhances the molecular electrophilicity, as compared to 3,6-diamino-9-[2-(methoxycarbonyl) phenyl]-9H-xanthen-9-ylium, R123. The reactivity of these diaminoxanthylium cations is discussed in the context of local and global softness in extended conjugated systems.