TY - JOUR
T1 - Theoretical study of the relations between structure and photophysical properties of model oligofluorenes with central keto defect
AU - Lukeš, Vladimír
AU - Šolc, Roland
AU - Lischka, Hans
AU - Kauffmann, Harald Friedrich
PY - 2009/12/24
Y1 - 2009/12/24
N2 - A systematic study of fluorenone and model oligofluorenes (trimer, pentamer, and heptamer) with a central keto defect was performed at ab initio Hartree-Fock (HF), density functional theory (DFT), configuration interaction singles (CIS), and time-dependent density functional theory (TD-DFT) levels. The main aim of this work was the investigation of the direct influence of the central keto defect on the optimal geometry, torsional potentials, and photophysical properties. From the structural point of view, the optimal all-trans electronic ground state geometries of studied oligomers exhibit a uniform torsion of ca. 44-45° (HF) or 37-38° (DFT). The optical excitation leads to the planarization of the fluorenone and fluorene fragments in the central part of the molecule (∼34° for CIS and ∼29° for TD-DFT). The computed excitation and fluorescence energies show a good agreement with the experiment. These presented theoretical results can be useful in designing novel fluorene-fluorenone optical materials as well as understanding of excitation-relaxation phenomena which may occur in various time-dependent optical experiments.
AB - A systematic study of fluorenone and model oligofluorenes (trimer, pentamer, and heptamer) with a central keto defect was performed at ab initio Hartree-Fock (HF), density functional theory (DFT), configuration interaction singles (CIS), and time-dependent density functional theory (TD-DFT) levels. The main aim of this work was the investigation of the direct influence of the central keto defect on the optimal geometry, torsional potentials, and photophysical properties. From the structural point of view, the optimal all-trans electronic ground state geometries of studied oligomers exhibit a uniform torsion of ca. 44-45° (HF) or 37-38° (DFT). The optical excitation leads to the planarization of the fluorenone and fluorene fragments in the central part of the molecule (∼34° for CIS and ∼29° for TD-DFT). The computed excitation and fluorescence energies show a good agreement with the experiment. These presented theoretical results can be useful in designing novel fluorene-fluorenone optical materials as well as understanding of excitation-relaxation phenomena which may occur in various time-dependent optical experiments.
UR - http://www.scopus.com/inward/record.url?scp=73349121642&partnerID=8YFLogxK
U2 - 10.1021/jp902658u
DO - 10.1021/jp902658u
M3 - Article
C2 - 19928889
AN - SCOPUS:73349121642
SN - 1089-5639
VL - 113
SP - 14141
EP - 14149
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 51
ER -