Wavelength-dependent photocycloreversion of the endoperoxides of 1,2,3,4-tetramethylanthracene and 1,2,3,4-tetramethyl-9,10-diphenylanthracene

✍ Scribed by E. Afshari; H.-D. Brauer; R. Schmidt; M. Lachgar; J. Rigaudy

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 469 KB
• Volume: 63
• Category: Article
• ISSN: 1010-6030
• DOI: 10.1016/1010-6030(92)85197-3

✦ Synopsis

A pronounced, graduated wavelength dependence of the quantum yield Q, of cycloreversion of the endoperoxides (POs) of 1,2,3,4-tetramethylanthracene (TMAPO) and 1,2,3,4-tetramethyl-9,10-diphenylanthracene (TMDPAPO) was observed. A comparison of the excited singlet state energies of the naphthalene chromophore of TMDPAPO with the steps in the graduation of Qc leads to an evaluation of the cycloreversion efficiencies from each of the upper excited singlet states S,: E,(S,) = 0.13, E,-(S,) = 0.07 and E&S,) = 0.67. These values are compatible with recent results of time-resolved measurements according to which the first C-O bond in PO cycloreversion cleaves within a time domain of about lo-l3 s.