Among several derivatives of 9-b%zoylanthracene investigated, only 9-bcnzoyl lC-cyanoanthraccnc having the largest Ao-\_O value showed a large temperature effect on the fluorescence intensity. This fact confirmed our previous supposition that in 9-czrbonyl dcrivativcs of anthracene there is efficien
Intersystem crossing in 9-carbonyl derivatives of anthracene
โ Scribed by T. Matsumoto; M. Sato; S. Hirayama
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- English
- Weight
- 355 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0009-2614
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โฆ Synopsis
An unusual temperature ,effect on ihe intensity of fluorescence of 9-carbonyl derivhtives of anthracene is observed: ihis is interpreted in terms of an intersystem crossing process from the lowest excited singlet state, !+r to the higher excited triplet state T,&_ ,.
Investigations of temperature effects on fluorescence spectra and on the quantum yields of anthracenk and.
๐ SIMILAR VOLUMES
A temperature dependent intersystem crossing rate is observed below ca. 170ยฐK for anthracene in methyl tetrahydrofuran. From the temperature dependence of the 0.0 bands in absorption and emission, this is interpreted as being due to slow lattice relaxation in the excited singlet state.
The major jR#g~a~ eIemnic ~l~a~~~ mrxkaaism from the first el~t~Rj~ly excited St singleE manifold of anthracene and its isotopic and chemical derivatives involves intersystem crossing (ISC) [ 1-15 1, which proceeds via two parallel mechanisms: (1) DirectSi-+ ISC [Sj to thestatistical first triplet
T&c growing-in of the anthraccnc triplet state has been mcasurcd in the cast of the anthracenc-NJUN-dicthylanthnc cxciplex system in hcxane. The anthracenc triplet state IS formed from the relaxed cxciplcv fluorescent state.
Fluorescence lifetimes Tf of anthracene, 9.10-diphenylanthracene and S-methylanthracene have heen measured as a function of pressure to 30 kbar at 77oK. An anomalous Whree-fold increase in rfr OEIserved for anthracene at high pressures. is attributed to prohibition of SI--WT2 intersystem crossing as