Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5399892 | Journal of Luminescence | 2014 | 8 Pages |
Abstract
The interaction between pyrenetetrasulphonate (PTS) and methyl viologen (MV2+) leads to a 1:1 charge transfer complex (CTC) in the concentration range below mmol Lâ1 of the ligands. Quantum mechanical calculations show the 1:1 complex having the planar moiety of PTS and the charges of the sulfonate groups stabilized by the twisted rings of the positively charged MV2+ species. The peculiar nature of PTS includes high fluorescence quantum yield (~1), clear specular UV-vis spectra and fluorescence emission images, as well similar S2âS0 and S3âS0 transitions as those of S1âS0, all of them exhibiting well resolved vibrational structure. MV2+ has well known electron-accepting properties that favor the complexation. These features were studied as a function of salt concentration and temperature dependences allowing a detailed comprehension of static and dynamic association processes. Quantum mechanical calculations show the 1:1 stabilization of PTS/MV2+. In addition the effect of urea on the CTC equilibrium is presented, as expected the additive acts towards the non-complexed species (solvated free ions). The fluorescence quenching of MV2+over PTS highlights is one of the applications of this effect for giant vesicles characterization.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Jeferson Santana, Katia R. Perez, Thiago B. Pisco, David D. Pavanelli, Décio Briotto Filho, Daisy Rezende, Eduardo Rezende Triboni, Francisco das Chagas Alves Lima, Janildo Lopes Magalhães, Iolanda Midea Cuccovia, Ligia F. Gomes, Mário J. Politi,