Application of surface-enhanced resonance Raman scattering (SERS) to the study of organic functional materials: electronic structure and charge transfer properties of 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene

Juan Soto; Elizabeth Imbarack; Isabel López-Tocón; Santiago Sánchez-Cortés; Juan C Otero; Patricio Leyton

doi:10.1039/c9ra01269a

Application of surface-enhanced resonance Raman scattering (SERS) to the study of organic functional materials: electronic structure and charge transfer properties of 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene

RSC Adv. 2019 May 9;9(25):14511-14519. doi: 10.1039/c9ra01269a. eCollection 2019 May 7.

Authors

Juan Soto¹, Elizabeth Imbarack², Isabel López-Tocón¹, Santiago Sánchez-Cortés³, Juan C Otero¹, Patricio Leyton²

Affiliations

¹ Department of Physical Chemistry, Faculty of Science, Andalucía Tech, Unidad Asociada IEM-CSIC 29071-Málaga Spain soto@uma.es.
² Instituto de Química, Pontificia Universidad Católica de Valparaiso Valparaiso Chile.
³ Instituto de Estructura de la Materia, IEM-CSIC Serrano 121 28006-Madrid Spain.

Abstract

The electron donor-acceptor properties of 9,10-bis((E)-2-(pyridin-4-yl)vinyl) anthracene (BP4VA) are studied by means of surface-enhanced Raman scattering (SERS) spectroscopy and vibronic theory of resonance Raman spectroscopy. The SERS spectra recorded in an electrochemical cell with a silver working electrode have been interpreted on the basis of resonance Raman vibronic theory assisted by DFT calculations. It is demonstrated that the adsorbate-metal interaction occurs through the nitrogen atom of the pyridyl moiety. Concerning the electron donor-acceptor properties of the adsorbate, it is shown that the charge transfer excited states of BP4VA are not optically active, in contrast, an internal transition to an excited state of BP4VA, which is localized in the anthracene framework, is strongly allowed. The charge transfer states will be populated by an ultrafast non-radiative process, that is, internal conversion. Thus, irradiation of BP4VA interacting with an appropriate surface creates an effective charge separation.