TY - JOUR
T1 - Enthalpy-Entropy Compensation Effect for Triplet Pair Dissociation of Intramolecular Singlet Fission in Phenylene Spacer-Bridged Hexacene Dimers
AU - Nakamura, Shunta
AU - Sakai, Hayato
AU - Fuki, Masaaki
AU - Kobori, Yasuhiro
AU - Tkachenko, Nikolai V.
AU - Hasobe, Taku
N1 - Funding Information:
This work was partially supported by JSPS KAKENHI Grant Numbers JP19H00888 and JP20K21174 and Grant-in-Aid for Transformative Research Areas, “Dynamic Exciton” (JP20H05832), to Y.K. and by JSPS KAKENHI Grant Nos. JP18H01957, JP18K19063, JP20H05234, JP20KK0120, and JP21H01908 to T.H., JP20K05652 to H.S., and JP20J13133 to S.N. This work was partially carried out by the joint research program of Molecular Photoscience Research Center, Kobe University, and the Research Program of “Five-star Alliance” in “NJRC Mater. & Dev”.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/7/22
Y1 - 2021/7/22
N2 - Hexacene (Hc) is highly promising for singlet fission (SF). However, the number of SFs in Hc is extremely limited. As far as Hc dimers in solution are concerned, there is no report on the observation of the dissociation process from a correlated triplet pair (TT) to an individual one. The emphasis in this study is on the first observation of the quantitative TT generation together with the orientation-dependent photophysical discussions for TT dissociation usingpara- andmeta-phenyl-bridged Hc dimers. Moreover, the activation enthalpies of Hc dimers in TT dissociation are smaller than those of pentacene (Pc) dimers, whereas the relative entropic contributions for Gibbs free energy of activation are much larger than the enthalpic ones in both Hc and Pc dimers. This implies that the vibrational motions are responsible for the intramolecular conformation changes associated with the TT dissociation. Consequently, “enthalpy-entropy compensation” has a large impact on the rate constants and quantum yields.
AB - Hexacene (Hc) is highly promising for singlet fission (SF). However, the number of SFs in Hc is extremely limited. As far as Hc dimers in solution are concerned, there is no report on the observation of the dissociation process from a correlated triplet pair (TT) to an individual one. The emphasis in this study is on the first observation of the quantitative TT generation together with the orientation-dependent photophysical discussions for TT dissociation usingpara- andmeta-phenyl-bridged Hc dimers. Moreover, the activation enthalpies of Hc dimers in TT dissociation are smaller than those of pentacene (Pc) dimers, whereas the relative entropic contributions for Gibbs free energy of activation are much larger than the enthalpic ones in both Hc and Pc dimers. This implies that the vibrational motions are responsible for the intramolecular conformation changes associated with the TT dissociation. Consequently, “enthalpy-entropy compensation” has a large impact on the rate constants and quantum yields.
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U2 - 10.1021/acs.jpclett.1c01430
DO - 10.1021/acs.jpclett.1c01430
M3 - Article
C2 - 34236876
AN - SCOPUS:85111173478
SN - 1948-7185
VL - 12
SP - 6457
EP - 6463
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 28
ER -