Article ID Journal Published Year Pages File Type
5418719 Journal of Molecular Structure: THEOCHEM 2007 6 Pages PDF
Abstract
Solvent effects on the s-trans/s-cis conformational equilibrium and electronic spectra of a simple 2,2′-bipyridine derivative have been analyzed on the basis of quantum mechanical computations using a solvent dielectric continuum model and time-dependent density functional theory (TD-DFT). Experimental data for the UV-spectra are also reported. The predicted spectra for the two conformations present significant differences in particular for the band appearing at higher wavelength, which corresponds to the HOMO → LUMO (π → π∗) electronic transition. Since experimental data for the UV-spectra display only small solvent effects, one can conclude that the population of the less stable s-cis conformation is small, even in a polar media such as water. This conclusion is confirmed by computations for s-trans/s-cis free energy differences as a function of the dielectric constant of the medium but contrasts with previously reported experimental estimations based on dipole moment measurements.
Related Topics
Physical Sciences and Engineering Chemistry Physical and Theoretical Chemistry
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