@article{NeuvonenNeuvonenKochetal.2012,
  author    = {Neuvonen, Kari and Neuvonen, Helmi and Koch, Andreas and Kleinpeter, Erich},
  title     = {Taft equation in the light of NBO computations introduction of a novel polar computational substituent constant scale sigma(q)* for alkyl groups},
  series = {Computational and theoretical chemistry},
  volume    = {981},
  journal   = {Computational and theoretical chemistry},
  number    = {2},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2210-271X},
  doi       = {10.1016/j.comptc.2011.11.044},
  pages     = {52 -- 58},
  year      = {2012},
  abstract  = {The validity of the Taft equation: log(k(R)/k(CH3)) = rho*sigma* + delta E-S was studied with the aid of NBO computational results concerning cyclohexyl esters RCOOC6H11 [R = Methyl, Ethyl, n-Propyl, Isopropyl, n-Butyl, Isobutyl, sec-Butyl, tert-Butyl, Neopentyl, CH(CH2CH3)(2), CH(CH3)C(CH3)(3), C(CH3)(2)CH2CH3, C(CH3)(2)C(CH3)(3), CH(CH3)(Np), CH(iPr)(tBu), C(Me)(Et)(iPr), C(Et)(2)(tBu) or C(Et)(iPr)(tBu)]. It was proved that the sigma*(alkyl) value is a composite substitutent constant including the polar and steric contributions. A novel computational sigma(q)* substituent constant scale is presented based on the NBO atomic charges of the alpha-carbon and the computational total steric exchange energies E(ster) of the cyclohexyl esters specified above. The method used offers a useful way to calculate sigma*(alkyl) values for alkyl groups for which experimental Taft's polar sigma* parameters are not available.},
  language  = {en}
}