The Alkyl Inductive Effect, II Theoretical Calculation of Inductive Parameters

Abstract

<jats:title>Abstract</jats:title><jats:p>Three models of alkyl groups, “derealization”, “through-the-bond”, and “electric field” models, are presented, all of which enable the calculation of σ<jats:sub>I </jats:sub>(R) from first principles, and excellent agreement is demonstrated for the calculated and experimental values of σ<jats:sub>I </jats:sub>(R) . For the “delocalization” model it is found that - σ<jats:sub>I</jats:sub> (R) = 0.0455 + 0.0232(1-1/n), where n is the number of C atoms in an n-alkyl group, and for an infinite C-chain R group, σ<jats:sub>I</jats:sub>( R<jats:sub>∞</jats:sub>) is - 0.0687, identical to the value found b y a different method in Part I of this series. The “through-the-bond” model gives - σ<jats:sub>I</jats:sub>(R) = - 0.0559 +<jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/Untitled-1.jpg" /></jats:alternatives></jats:inline-formula>, where C<jats:sub>i</jats:sub> is the number of C-atoms in the i <jats:sup>th</jats:sup> position from X in RX; and for the “electric field” model, we obtain - σ<jats:sub>I</jats:sub>(R) = 0.0463 + 0.0102 <jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/Untitled-2.jpg" /></jats:alternatives></jats:inline-formula>, where d<jats:sub>i</jats:sub> is the calculated distance from C<jats:sub>1</jats:sub> to C<jats:sub>n</jats:sub> in the most probable conformation of the R-group. It is concluded that Taft's σ<jats:sub>I</jats:sub>(R) values have a real significance whether or not the physical and chemical effects of alkyl substitution reside ultimately in an internal induction mechanism, or in alkyl group polarization by charged centers in the molecule, or a combination of the two.</jats:p>

Cations Coordination‐Regulated Reversibility Enhancement for Aqueous Zn‐Ion Battery

“…The influence of the ethyl substituent on the nitrogen atom leads to the shifting of the electron cloud density in the whole molecule, which causes the polarization of the molecule, and changes the electron‐donating capability due to the “inductive effect”. [ 27,30 ]…”

“…Based on the careful consideration of the “green” characteristic, low‐cost, and steric effect of ligand, [ 26 ] amine‐containing small molecules, which are featured with lone pair electrons, are regarded as promising candidates to construct the expected electrolyte system. Interestingly, we noted that the coordination effects of ligands could be further modulated by the “induction effect” [ 27 ] of the substituent. Here we chose the CH 2 CH 3 substituent group for modifying the amine group.…”

“…The influence of the ethyl substituent on the nitrogen atom leads to the shifting of the electron cloud density in the whole molecule, which causes the polarization of the molecule, and changes the electron-donating capability due to the "inductive effect". [27,30] As shown in Figure 2a, the four typical molecules present different binding energies with Zn 2+ cations based on the DFT simulation. Comparing to the water molecule, all these molecules show lower binding energy toward Zn 2+ .…”