Abstract
A new design strategy to activate aggregation-induced emission (AIE) in pyrene chromophores is reported. In a previous report, we demonstrated that highly twisted N,N-dialkylamines of anthracene and naphthalene induce drastic AIE when these donors are introduced at appropriate positions to stabilize the S1/S0 minimum energy conical intersection (MECI). In the present study, this design strategy was applied to pyrene: the introduction of N,N-dimethylamine substituents at the 4,5-positions of pyrene, the so-called K-region, are likely to stabilize MECIs. To examine this hypothesis, four novel pyrene derivatives, which contain highly twisted N,N-dimethylamino groups at the 4- (4-Py), 4,5- (4,5-Py), 1- (1-Py), or 1,6-positions (1,6-Py) were tested. The nonradiative transitions of 4,5-Py are highly efficient (knr = 57.1 × 107 s-1), so that its fluorescence quantum yield in acetonitrile decreases to φfl = 0.04. The solid-state fluorescence of 4,5-Py is efficient (φfl = 0.49). In contrast, 1,6-Py features strong fluorescence (φfl = 0.48) with a slow nonradiative transition (knr = 11.0 × 107 s-1) that is subject to severe quenching (φfl = 0.03) in the solid state. These results underline that the chemistry of the pyrene K-region is intriguing, both from a photophysical perspective and with respect to materials science.
| Original language | English |
|---|---|
| Pages (from-to) | 6865-6873 |
| Number of pages | 9 |
| Journal | Journal of Organic Chemistry |
| Volume | 82 |
| Issue number | 13 |
| DOIs | |
| Publication status | Published - Jul 7 2017 |
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All Science Journal Classification (ASJC) codes
- Organic Chemistry
Cite this
The K-Region in Pyrenes as a Key Position to Activate Aggregation-Induced Emission : Effects of Introducing Highly Twisted N,N-Dimethylamines. / Sasaki, Shunsuke; Suzuki, Satoshi; Igawa, Kazunobu; Morokuma, Keiji; Konishi, Gen Ichi.
In: Journal of Organic Chemistry, Vol. 82, No. 13, 07.07.2017, p. 6865-6873.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The K-Region in Pyrenes as a Key Position to Activate Aggregation-Induced Emission
T2 - Effects of Introducing Highly Twisted N,N-Dimethylamines
AU - Sasaki, Shunsuke
AU - Suzuki, Satoshi
AU - Igawa, Kazunobu
AU - Morokuma, Keiji
AU - Konishi, Gen Ichi
PY - 2017/7/7
Y1 - 2017/7/7
N2 - A new design strategy to activate aggregation-induced emission (AIE) in pyrene chromophores is reported. In a previous report, we demonstrated that highly twisted N,N-dialkylamines of anthracene and naphthalene induce drastic AIE when these donors are introduced at appropriate positions to stabilize the S1/S0 minimum energy conical intersection (MECI). In the present study, this design strategy was applied to pyrene: the introduction of N,N-dimethylamine substituents at the 4,5-positions of pyrene, the so-called K-region, are likely to stabilize MECIs. To examine this hypothesis, four novel pyrene derivatives, which contain highly twisted N,N-dimethylamino groups at the 4- (4-Py), 4,5- (4,5-Py), 1- (1-Py), or 1,6-positions (1,6-Py) were tested. The nonradiative transitions of 4,5-Py are highly efficient (knr = 57.1 × 107 s-1), so that its fluorescence quantum yield in acetonitrile decreases to φfl = 0.04. The solid-state fluorescence of 4,5-Py is efficient (φfl = 0.49). In contrast, 1,6-Py features strong fluorescence (φfl = 0.48) with a slow nonradiative transition (knr = 11.0 × 107 s-1) that is subject to severe quenching (φfl = 0.03) in the solid state. These results underline that the chemistry of the pyrene K-region is intriguing, both from a photophysical perspective and with respect to materials science.
AB - A new design strategy to activate aggregation-induced emission (AIE) in pyrene chromophores is reported. In a previous report, we demonstrated that highly twisted N,N-dialkylamines of anthracene and naphthalene induce drastic AIE when these donors are introduced at appropriate positions to stabilize the S1/S0 minimum energy conical intersection (MECI). In the present study, this design strategy was applied to pyrene: the introduction of N,N-dimethylamine substituents at the 4,5-positions of pyrene, the so-called K-region, are likely to stabilize MECIs. To examine this hypothesis, four novel pyrene derivatives, which contain highly twisted N,N-dimethylamino groups at the 4- (4-Py), 4,5- (4,5-Py), 1- (1-Py), or 1,6-positions (1,6-Py) were tested. The nonradiative transitions of 4,5-Py are highly efficient (knr = 57.1 × 107 s-1), so that its fluorescence quantum yield in acetonitrile decreases to φfl = 0.04. The solid-state fluorescence of 4,5-Py is efficient (φfl = 0.49). In contrast, 1,6-Py features strong fluorescence (φfl = 0.48) with a slow nonradiative transition (knr = 11.0 × 107 s-1) that is subject to severe quenching (φfl = 0.03) in the solid state. These results underline that the chemistry of the pyrene K-region is intriguing, both from a photophysical perspective and with respect to materials science.
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UR - http://www.scopus.com/inward/citedby.url?scp=85022331953&partnerID=8YFLogxK
U2 - 10.1021/acs.joc.7b00996
DO - 10.1021/acs.joc.7b00996
M3 - Article
AN - SCOPUS:85022331953
VL - 82
SP - 6865
EP - 6873
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 13
ER -