| Autor: |
Szatylowicz H; Faculty of Chemistry, Warsaw University of Technology , Noakowskiego 3, 00-664 Warsaw, Poland., Jezuita A; Faculty of Chemistry, Opole University , Oleska 48, 45-052 Opole, Poland., Siodła T; Faculty of Chemistry, Adam Mickiewicz University , Umultowska 89b, 61-614 Poznań, Poland., Varaksin KS; Department Organic Chemistry, Omsk F. M. Dostoevsky State University , Mira 55A, 644077 Omsk, Russia., Ejsmont K; Faculty of Chemistry, Opole University , Oleska 48, 45-052 Opole, Poland., Madura ID; Faculty of Chemistry, Warsaw University of Technology , Noakowskiego 3, 00-664 Warsaw, Poland., Krygowski TM; Department of Chemistry, Warsaw University , Pasteura 1, 02-093 Warsaw, Poland. |
| Abstrakt: |
The influence of a solvent on the substituent effect (SE) in 1,4-disubstituted derivatives of benzene (BEN), cyclohexa-1,3-diene (CHD), and bicyclo[2.2.2]octane (BCO) is studied by the use of polarizable continuum model method. In all X-R-Y systems for the functional group Y (NO 2 , COOH, OH, and NH 2 ), the following substituents X have been chosen: NO 2 , CHO, H, OH, and NH 2 . The substituent effect is characterized by the charge of the substituent active region (cSAR(X)), substituent effect stabilization energy (SESE), and substituent constants σ or F descriptors, the functional groups by cSAR(Y), whereas π-electron delocalization of transmitting moieties (BEN and CHD) is characterized by a geometry-based index, harmonic oscillator model of aromaticity. All computations were carried out by means of B3LYP/6-311++G(d,p) method. An application of quantum chemistry SE models (cSAR and SESE) allows to compare the SE in water solutions and in the gas phase. Results of performed analyses indicate an enhancement of the SE by water. The obtained Hammett-type relationships document different nature of interactions between Y and X in aromatic and olefinic systems (a coexistence of resonance and inductive effects) than in saturated ones (only the inductive effect). An increase of electric permittivity clearly enhances communications between X and Y for BEN and CHD systems. |
