Abstract
Singlet and triplet excited-state dynamics of anthanthrene and anthanthrone derivatives in solution are studied. Triisopropylsilyl- (TIPS) or H-terminated ethynyl groups are used to tune the singlet and triplet energies to enable their potential applications in singlet fission and triplet fusion processes. Time-resolved optical and electron paramagnetic resonance (EPR) spectroscopies are used to obtain a mechanistic understanding of triplet formation. The anthanthrene derivatives form triplet states efficiently at a rate (ca. 107 s−1) comparable to radiative singlet fluorescence processes with approximately 30 % triplet yields, despite their large S1-T1 energy gap (>1 eV) and the lack of carbonyl groups. In contrast, anthanthrone has a higher triplet yield (50±10 %) with a faster intersystem crossing rate (2.7 × 108 s−1) because of the n-π* character of the S1←S0 transition. Analysis of time-resolved spin-polarized EPR spectra of these compounds reveals that the triplet states are primarily generated by the spin-orbit-induced intersystem crossing mechanism. However, at high concentrations, the EPR spectrum of the 4,6,10,14-tetrakis(TIPS-ethynyl)anthanthrene triplet state shows a significant contribution from a non-Boltzmann population of the ms=0 spin sublevel, which is characteristic of triplet formation by singlet fission.
| Original language | English |
|---|---|
| Journal | ChemPlusChem |
| DOIs | |
| Publication status | Accepted/In press - Jan 1 2019 |
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Keywords
- anthanthrene
- anthanthrone
- photochemistry
- singlet fission
- spin-orbit intersystem crossing
ASJC Scopus subject areas
- Chemistry(all)
Cite this
Competition between Singlet Fission and Spin-Orbit-Induced Intersystem Crossing in Anthanthrene and Anthanthrone Derivatives. / Jue Bae, Youn; Krzyaniak, Matthew D.; Majewski, Marek B.; Desroches, Maude; Morin, Jean François; Wu, Yi Lin; Wasielewski, Michael R.
In: ChemPlusChem, 01.01.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Competition between Singlet Fission and Spin-Orbit-Induced Intersystem Crossing in Anthanthrene and Anthanthrone Derivatives
AU - Jue Bae, Youn
AU - Krzyaniak, Matthew D.
AU - Majewski, Marek B.
AU - Desroches, Maude
AU - Morin, Jean François
AU - Wu, Yi Lin
AU - Wasielewski, Michael R
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Singlet and triplet excited-state dynamics of anthanthrene and anthanthrone derivatives in solution are studied. Triisopropylsilyl- (TIPS) or H-terminated ethynyl groups are used to tune the singlet and triplet energies to enable their potential applications in singlet fission and triplet fusion processes. Time-resolved optical and electron paramagnetic resonance (EPR) spectroscopies are used to obtain a mechanistic understanding of triplet formation. The anthanthrene derivatives form triplet states efficiently at a rate (ca. 107 s−1) comparable to radiative singlet fluorescence processes with approximately 30 % triplet yields, despite their large S1-T1 energy gap (>1 eV) and the lack of carbonyl groups. In contrast, anthanthrone has a higher triplet yield (50±10 %) with a faster intersystem crossing rate (2.7 × 108 s−1) because of the n-π* character of the S1←S0 transition. Analysis of time-resolved spin-polarized EPR spectra of these compounds reveals that the triplet states are primarily generated by the spin-orbit-induced intersystem crossing mechanism. However, at high concentrations, the EPR spectrum of the 4,6,10,14-tetrakis(TIPS-ethynyl)anthanthrene triplet state shows a significant contribution from a non-Boltzmann population of the ms=0 spin sublevel, which is characteristic of triplet formation by singlet fission.
AB - Singlet and triplet excited-state dynamics of anthanthrene and anthanthrone derivatives in solution are studied. Triisopropylsilyl- (TIPS) or H-terminated ethynyl groups are used to tune the singlet and triplet energies to enable their potential applications in singlet fission and triplet fusion processes. Time-resolved optical and electron paramagnetic resonance (EPR) spectroscopies are used to obtain a mechanistic understanding of triplet formation. The anthanthrene derivatives form triplet states efficiently at a rate (ca. 107 s−1) comparable to radiative singlet fluorescence processes with approximately 30 % triplet yields, despite their large S1-T1 energy gap (>1 eV) and the lack of carbonyl groups. In contrast, anthanthrone has a higher triplet yield (50±10 %) with a faster intersystem crossing rate (2.7 × 108 s−1) because of the n-π* character of the S1←S0 transition. Analysis of time-resolved spin-polarized EPR spectra of these compounds reveals that the triplet states are primarily generated by the spin-orbit-induced intersystem crossing mechanism. However, at high concentrations, the EPR spectrum of the 4,6,10,14-tetrakis(TIPS-ethynyl)anthanthrene triplet state shows a significant contribution from a non-Boltzmann population of the ms=0 spin sublevel, which is characteristic of triplet formation by singlet fission.
KW - anthanthrene
KW - anthanthrone
KW - photochemistry
KW - singlet fission
KW - spin-orbit intersystem crossing
UR - http://www.scopus.com/inward/record.url?scp=85070863254&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85070863254&partnerID=8YFLogxK
U2 - 10.1002/cplu.201900410
DO - 10.1002/cplu.201900410
M3 - Article
AN - SCOPUS:85070863254
JO - ChemPlusChem
JF - ChemPlusChem
SN - 2192-6506
ER -