Browsing by Author "Caroli Rezende, Marcos"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Solvatochromism and electrophilicity
    (ELSEVIER SCIENCE BV, 2011) Caroli Rezende, Marcos; Dominguez, Moises; Aracena, Andres; Millan, Daniela
    Solvatochromic dyes that exhibit a negative or a positive behaviour may be distinguished and their solvatochromism predicted with the aid of DFT-based indices, such as their electrophilicity omega, hardness eta and by the Fukui electrophilic functions f(G)(+) of the donor and acceptor moieties of the molecule, calculated in the gas-phase and in solvents treated as polarised continua. The protocol was successfully applied to 10 examples of phenolate betaines from the literature, five of them exhibiting a negative and five a positive solvatochromism. (C) 2011 Elsevier B.V. All rights reserved.
  • Thumbnail Image
    Item
    Theoretical Substituent Electrophilicities
    (SOC BRASILEIRA QUIMICA, 2011) Caroli Rezende, Marcos; Millan, Daniela
    A Hammett-like equation, relating theoretical global and substituent electrophilicities, is derived for substituted ethylenes and benzoic acids, allowing the calculation of electrophilic substituent constants a.. Correlations are given between the theoretical a, constants and kinetic or thermodynamic parameters of various chemical processes from the literature. Though electrophilic substituent constants are formally similar to the Hammett constants, they are derived from entirely different theoretical postulates. The similarities and differences between the two sets of constants are discussed and rationalized in terms of the definition of the electrophilic power of a chemical species.