Cargando…
Intramolecular Charge-Transfer Excited-State Processes in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ* State
[Image: see text] The structural processes leading to dual fluorescence of 4-(dimethylamino)benzonitrile in the gas phase and in acetonitrile solvent were investigated using a combination of multireference configuration interaction (MRCI) and the second-order algebraic diagrammatic construction (ADC...
Autores principales: | , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical
Society
2015
|
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4476306/ https://www.ncbi.nlm.nih.gov/pubmed/25989536 http://dx.doi.org/10.1021/acs.jpca.5b03282 |
_version_ | 1782377581340786688 |
---|---|
author | Georgieva, Ivelina Aquino, Adélia J. A. Plasser, Felix Trendafilova, Natasha Köhn, Andreas Lischka, Hans |
author_facet | Georgieva, Ivelina Aquino, Adélia J. A. Plasser, Felix Trendafilova, Natasha Köhn, Andreas Lischka, Hans |
author_sort | Georgieva, Ivelina |
collection | PubMed |
description | [Image: see text] The structural processes leading to dual fluorescence of 4-(dimethylamino)benzonitrile in the gas phase and in acetonitrile solvent were investigated using a combination of multireference configuration interaction (MRCI) and the second-order algebraic diagrammatic construction (ADC(2)) methods. Solvent effects were included on the basis of the conductor-like screening model. The MRCI method was used for computing the nonadiabatic interaction between the two lowest excited ππ* states (S(2)(L(a), CT) and S(1)(L(b), LE)) and the corresponding minimum on the crossing seam (MXS) whereas the ADC(2) calculations were dedicated to assessing the role of the πσ* state. The MXS structure was found to have a twisting angle of ∼50°. The branching space does not contain the twisting motion of the dimethylamino group and thus is not directly involved in the deactivation process from S(2) to S(1). Polar solvent effects are not found to have a significant influence on this situation. Applying C(s) symmetry restrictions, the ADC(2) calculations show that CCN bending leads to a strong stabilization and to significant charge transfer (CT). Nevertheless, this structure is not a minimum but converts to the local excitation (LE) structure on releasing the symmetry constraint. These findings suggest that the main role in the dynamics is played by the nonadiabatic interaction of the LE and CT states and that the main source for the dual fluorescence is the twisted internal charge-transfer state in addition to the LE state. |
format | Online Article Text |
id | pubmed-4476306 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | American Chemical
Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-44763062015-06-23 Intramolecular Charge-Transfer Excited-State Processes in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ* State Georgieva, Ivelina Aquino, Adélia J. A. Plasser, Felix Trendafilova, Natasha Köhn, Andreas Lischka, Hans J Phys Chem A [Image: see text] The structural processes leading to dual fluorescence of 4-(dimethylamino)benzonitrile in the gas phase and in acetonitrile solvent were investigated using a combination of multireference configuration interaction (MRCI) and the second-order algebraic diagrammatic construction (ADC(2)) methods. Solvent effects were included on the basis of the conductor-like screening model. The MRCI method was used for computing the nonadiabatic interaction between the two lowest excited ππ* states (S(2)(L(a), CT) and S(1)(L(b), LE)) and the corresponding minimum on the crossing seam (MXS) whereas the ADC(2) calculations were dedicated to assessing the role of the πσ* state. The MXS structure was found to have a twisting angle of ∼50°. The branching space does not contain the twisting motion of the dimethylamino group and thus is not directly involved in the deactivation process from S(2) to S(1). Polar solvent effects are not found to have a significant influence on this situation. Applying C(s) symmetry restrictions, the ADC(2) calculations show that CCN bending leads to a strong stabilization and to significant charge transfer (CT). Nevertheless, this structure is not a minimum but converts to the local excitation (LE) structure on releasing the symmetry constraint. These findings suggest that the main role in the dynamics is played by the nonadiabatic interaction of the LE and CT states and that the main source for the dual fluorescence is the twisted internal charge-transfer state in addition to the LE state. American Chemical Society 2015-05-19 2015-06-18 /pmc/articles/PMC4476306/ /pubmed/25989536 http://dx.doi.org/10.1021/acs.jpca.5b03282 Text en Copyright © 2015 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
spellingShingle | Georgieva, Ivelina Aquino, Adélia J. A. Plasser, Felix Trendafilova, Natasha Köhn, Andreas Lischka, Hans Intramolecular Charge-Transfer Excited-State Processes in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ* State |
title | Intramolecular Charge-Transfer Excited-State Processes
in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ*
State |
title_full | Intramolecular Charge-Transfer Excited-State Processes
in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ*
State |
title_fullStr | Intramolecular Charge-Transfer Excited-State Processes
in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ*
State |
title_full_unstemmed | Intramolecular Charge-Transfer Excited-State Processes
in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ*
State |
title_short | Intramolecular Charge-Transfer Excited-State Processes
in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ*
State |
title_sort | intramolecular charge-transfer excited-state processes
in 4-(n,n-dimethylamino)benzonitrile: the role of twisting and the πσ*
state |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4476306/ https://www.ncbi.nlm.nih.gov/pubmed/25989536 http://dx.doi.org/10.1021/acs.jpca.5b03282 |
work_keys_str_mv | AT georgievaivelina intramolecularchargetransferexcitedstateprocessesin4nndimethylaminobenzonitriletheroleoftwistingandthepsstate AT aquinoadeliaja intramolecularchargetransferexcitedstateprocessesin4nndimethylaminobenzonitriletheroleoftwistingandthepsstate AT plasserfelix intramolecularchargetransferexcitedstateprocessesin4nndimethylaminobenzonitriletheroleoftwistingandthepsstate AT trendafilovanatasha intramolecularchargetransferexcitedstateprocessesin4nndimethylaminobenzonitriletheroleoftwistingandthepsstate AT kohnandreas intramolecularchargetransferexcitedstateprocessesin4nndimethylaminobenzonitriletheroleoftwistingandthepsstate AT lischkahans intramolecularchargetransferexcitedstateprocessesin4nndimethylaminobenzonitriletheroleoftwistingandthepsstate |