From Oligo(Phenyleneethynylene) Monomers to Supramolecular Helices: The Role of Intermolecular Interactions in Aggregation |
| |
Authors: | Berta Ferná ndez,Zulema Ferná ndez,Emilio Quiñ oá ,Fé lix Freire |
| |
Affiliation: | 1.Departamento de Química Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain;2.Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; (Z.F.); (E.Q.) |
| |
Abstract: | Supramolecular helices that arise from the self-assembly of small organic molecules via non-covalent interactions play an important role in the structure and properties of the corresponding materials. Here we study the supramolecular helical aggregation of oligo(phenyleneethynylene) monomers from a theoretical point of view, always guiding the studies with experimentally available data. In this way, by systematically increasing the number of monomer units, optimized n-mer geometries are obtained along with the corresponding absorption and circular dichroism spectra. For the geometry optimizations we use density functional theory together with the B3LYP-D3 functional and the 6–31G** basis set. For obtaining the spectra we resort to time-dependent density functional theory using the CAM-B3LYP functional and the 3–21G basis set. These combinations of density functional and basis set were selected after systematic convergence studies. The theoretical results are analyzed and compared to the experimentally available spectra, observing a good agreement. |
| |
Keywords: | oligo(phenyleneethynylene) monomer aggregation supramolecular helices density functional theory and time-dependent density functional theory calculations geometry optimizations absorption spectra electron circular dichroism spectra |
|
|