TY - JOUR
T1 - Intramolecular and metal-to-molecule charge transfer electronic resonances in the surface-enhanced raman scattering of 1,4-Bis((E)-2-(pyridin-4-yl)vinyl)naphthalene
AU - López-Tocón, Isabel
AU - Imbarack, Elizabeth
AU - Soto, Juan
AU - Sanchez-Cortes, Santiago
AU - LEYTON BONGIORNO, PATRICIO ALEJANDRO
AU - Otero, Juan Carlos
N1 - Publisher Copyright:
© 2019 by the authors.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/12/17
Y1 - 2019/12/17
N2 - Electrochemical surface-enhanced Raman scattering (SERS) of the cruciform system 1,4-bis((E)-2-(yridine-4-yl)vinyl)naphthalene (bpyvn) was recorded on nanostructured silver surfaces at different electrode potentials by using excitation laser lines of 785 and 514.5 nm. SERS relative intensities were analyzed on the basis of the resonance Raman vibronic theory with the help of DFT calculations. The comparison between the experimental and the computed resonance Raman spectra calculated for the first five electronic states of the Ag2-bpyvn surface complex model points out that the selective enhancement of the SERS band recorded at about 1600 cm−1, under 785 nm excitation, is due to a resonant Raman process involving a photoexcited metal-to-molecule charge transfer state of the complex, while the enhancement of the 1570 cm−1 band using 514.5 nm excitation is due to an intramolecular π→π* electronic transition localized in the naphthalenyl framework, resulting in a case of surface-enhanced resonance Raman spectrum (SERRS). Thus, the enhancement of the SERS bands of bpyvn is controlled by a general chemical enhancement mechanism in which different resonance processes of the overall electronic structure of the metal-molecule system are involved.
AB - Electrochemical surface-enhanced Raman scattering (SERS) of the cruciform system 1,4-bis((E)-2-(yridine-4-yl)vinyl)naphthalene (bpyvn) was recorded on nanostructured silver surfaces at different electrode potentials by using excitation laser lines of 785 and 514.5 nm. SERS relative intensities were analyzed on the basis of the resonance Raman vibronic theory with the help of DFT calculations. The comparison between the experimental and the computed resonance Raman spectra calculated for the first five electronic states of the Ag2-bpyvn surface complex model points out that the selective enhancement of the SERS band recorded at about 1600 cm−1, under 785 nm excitation, is due to a resonant Raman process involving a photoexcited metal-to-molecule charge transfer state of the complex, while the enhancement of the 1570 cm−1 band using 514.5 nm excitation is due to an intramolecular π→π* electronic transition localized in the naphthalenyl framework, resulting in a case of surface-enhanced resonance Raman spectrum (SERRS). Thus, the enhancement of the SERS bands of bpyvn is controlled by a general chemical enhancement mechanism in which different resonance processes of the overall electronic structure of the metal-molecule system are involved.
KW - Charge transfer
KW - Computational spectra
KW - DFT calculations
KW - Resonance Raman
KW - SERS
UR - http://www.scopus.com/inward/record.url?scp=85076633222&partnerID=8YFLogxK
U2 - 10.3390/molecules24244622
DO - 10.3390/molecules24244622
M3 - Article
C2 - 31861152
AN - SCOPUS:85076633222
VL - 24
JO - Molecules
JF - Molecules
SN - 1420-3049
IS - 24
M1 - 4622
ER -