Photophysics of the second excited singlet states of cyclic enethiones

✍ Scribed by V. Pushkara Rao; R.P. Steer

• Book ID: 103991754
• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 878 KB
• Volume: 47
• Category: Article
• ISSN: 1010-6030
• DOI: 10.1016/1010-6030(89)87072-8

✦ Synopsis

The spectroscopic and photophysical parameters of the second excited singlet states of several enethiones have been measured in inert perfluoroalkane solvents. Two rigid, related enethiones, l,ldimethyl-Z-thioxo-l,Zdihydronaphthalene and thiocoumarin, behave in accordance with the energy gap law and decay predominately via SZ -A-+ S1 w T, . 1,1,3-Trimethyl-2-thioxo-1,2dihydronaphthalene, with a methyl group at an sp' carbon cy to the thiocarbonyl moiety, exhibits a much faster non-radiative decay rate. Thioisophorone and 4H-pyran-4-thione are structurally flexible and decay non-radiatively from S2 at rates much faster than the rigid bicychc enethione, thioverbenone. The results are rationalized in terms of the theory of radiationless transitions.