Anomalous fluorescence and low-temperature absorption spectra of naphtho[1,8-cd][1,2,6] thiadiazine and its derivatives: an example of second excited state emission (S2 → S0)
✍ Scribed by B.F. Plummer; Z.Y. Al-Saigh
- Publisher
- Elsevier Science
- Year
- 1982
- Tongue
- English
- Weight
- 411 KB
- Volume
- 91
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
An anomalous fluorcsccnce near 380 nm is dctcctcd from heptanc soluuons on naphtho[ l,S-cd][ 1,2,6] thrsdrazmc (I), 6,7drhydroaccnaphthoI5.6-cd] [ I,?,61 thiadrxonc (2), Its unsaturated dcnvatrvc (4). and the tctrachloro denvattvc of I (3), when these substances arc excrtcd Into theSo -S2 absorpuon band near 350 nm Cwrtatron spectra vent>? that Ss -L So fluorescence is occurring. The mcasurcd bfctimcs of each fiuorescencc are 2 2.3 3,0.3.0 4 ns rcspcclncly for I, 2.3. and 4. Radrahve and non-radrauvc rate constants arc prcscntcd. Compounds I and 2 cvhrbit unusual low-tcmpcrr turc absorphon spectra at 77 K m 3-mcthylpcntane rnatrL\ The dtsappcarancc of the long-wavclcngth tranu~~on at 650 nm IS accompanied by a new transihon near 450 nm at 77 Ii. It IS theorucd that a ground-state drmcr can c\plsm these obscrvauons.