• Photochemical cyclization of thioformanilides by chloranil. Steady-state and time-resolved study

JUAN E. ARGÜELLO; VALENTINA REY; GABRIELA OKSDATH MANSILLA; LUCIANA C. SCHMIDT; ALICIA B. PEÑÉÑORY

Foz Iguazú

Congreso; 12th Latin American Conference on Physical Organic Chemistry” (CLAFQO 12); 2013

PHOTOCHEMICAL CYCLIZATION OF THIOFORMANILIDES BY CHLORANIL. STEADY-STATE AND TIME-RESOLVED STUDIES   Juan E. Argüello, Valentina Rey, Gabriela Oksdath-Mansilla, Luciana C. Schmidt and Alicia B. Peñéñory.   INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, 5000, Argentina. jea@fcq.unc.edu,ar     The photochemical behavior of a number of thioformanilides, sensitized by triplet chloranil (CA), was investigated by nanosecond laser flash photolysis and steady-state irradiation in toluene, CH2Cl2 and MeCN. The nature of the transients detected upon 355-nm laser excitation was independent of the molecular structure of the thiocarbonyl compound but strongly affected by the solvent polarity. In particular, in CH2Cl2 the quenching process of triplet CA by N-phenylthiobenzamide was accompanied by H-transfer, with formation of the semiquinone CAH· radical. In contrast, a charge transfer process with formation of the radical anion CA·-, occurred in MeCN (eqn. 1 and Figure 1).