%0 Journal Article %T Nitro End Groups Remarkable Vibrational Reporters for Charge Transfer in the Excited States of Oligo(p-phenyleneethynylene)-Bridged Donor-Acceptor Dyads %+ Adam Mickiewicz University in Poznań (UAM) %+ Institut de Physique de Rennes (IPR) %+ Institut des Sciences Chimiques de Rennes (ISCR) %+ Université des Sciences et de la Technologie Houari Boumediene = University of Sciences and Technology Houari Boumediene [Alger] (USTHB) %+ Australian National University (ANU) %+ Julius-Maximilians-Universität Würzburg (JMU) %A Kubicki, J. %A Lorenc, Maciej %A Cochelin, P. %A Mongin, O. %A Amar, A. %A Boucekkine, A. %A Gaje, A. %A Humphrey, M.G. %A Morshedi, M. %A Lorenzen, S. %A Rauch, F. %A Scheufler, C. %A Marder, T.B. %A Paul, Frédéric %Z University of the Philippines, UPAustralian Research Council, ARCMinisterstwo Nauki i Szkolnictwa Wyższego, MNiSWCentre National de la Recherche Scientifique, CNRS 1194 %< avec comité de lecture %@ 1932-7447 %J Journal of Physical Chemistry C %I American Chemical Society %V 124 %N 18 %P 9755-9764 %8 2020-05-07 %D 2020 %R 10.1021/acs.jpcc.0c01532 %K Absorption spectroscopy %K Charge transfer %K Chromophores %K Ground state %K Light absorption %K Nitrogen oxides %K Charge transfer process %K DFT calculation %K Donor and acceptor %K Donor-acceptor dyads %K Phenyleneethynylene %K Photophysical behavior %K Push-pull chromophores %K Time-resolved infrared absorption spectroscopy %K Excited states %Z Physics [physics] %Z Chemical SciencesJournal articles %X The D-π-A dyads [(n-Hex)2N(1,4-C6H4)]CC[(1,4-C6H4)NO2] (1) and [(n-Hex)2N(1,4-C6H4)]CC(1,4-C6H4)CC[(1,4-C6H4)NO2] (2) have been studied by ultrafast time-resolved infrared absorption spectroscopy. After excitation into their singlet charge-transfer (1CT) state, a fast decay (ca. 6 ps for 1 and 1 ps for 2) of the initially populated singlet state into a ground state (major pathway) and a longer lived excited state (possibly the triplet state) is observed. The nitro and alkyne groups were used as vibrational reporters to probe the changes induced by the charge-transfer process. For the first time, we confirm experimentally that these changes are consistent with expectations based on the traditional valence-bond representations of the CT states of these push-pull chromophores. An almost identical charge transfer takes place in the two dyads, despite π-bridges of different lengths between the donor and acceptor groups. Complementary DFT calculations support the experimental assignments and have helped clarify the photophysical behavior of 1 and 2. %G English %2 https://univ-rennes.hal.science/hal-02862821/document %2 https://univ-rennes.hal.science/hal-02862821/file/Kubicki%20et%20al-2020-Nitro%20End-Groups.pdf %L hal-02862821 %U https://univ-rennes.hal.science/hal-02862821 %~ UNIV-RENNES1 %~ CNRS %~ INSA-RENNES %~ ENSC-RENNES %~ OSUR %~ ISCR %~ SCR_OMC2012 %~ IPR %~ SCR_CPM %~ ISCR-CTI %~ ZZ-IPR-MN %~ STATS-UR1 %~ UR1-SPM %~ INC-CNRS %~ UR1-UFR-SPM %~ UR1-HAL %~ ISCR-CORINT %~ UR1-SDLM %~ IPR-ML %~ TEST-UR-CSS %~ UNIV-RENNES %~ INSA-GROUPE %~ ISCR-CORINT1 %~ ISCR-CORINT2 %~ TEST-HALCNRS %~ UR1-MMS %~ ISCR-CORINT3 %~ TEST2-HALCNRS