Fotoquímica de chalconas fluoradas no estado sólido

Abstract

Recebido em 14/3/01; aceito em 20/6/01 PHOTOCHEMISTRY OF FLUORINATED CHALCONES IN THE SOLID STATE. Chalcone and its fluorinated derivatives were synthesized and photolyzed in the solid state. UV irradiation of chalcone and its monosubstituted fluorine derivatives (3-and 4-fluorchalcone) resulted in a mixture of anti-head-head (g-truxinic), sin-head-tail (a-truxilic) and anti-head-tail (e-truxilic) dimers. On the other hand, upon irradiation of 3,4-and 3,5-difluorchalcone a stereoselective formation of the a-truxilic photodimer was observed, whereas for 2-substituted chalcones (2,3-difluorchalcone, 2,5-difluorchalcone, 2,6-difluorchalcone and 2,3,4-trifluorchalcone) the b-truxilic dimer was stereoselectively obtained. 2',3',4',5',6'-pentafluorchalcone was the less reactive of all chalcones studied and at least one of the possible photodimers, i.e the anti-head-head isomer, was identified. Irradiation of polyfluorinated chalcones such as 2,3,5,6-tetrafluor-, 2,3,4,5,6-pentafluor-, and 2,2',3,3',4,4',5,5',6,6'-decafluorchalcone led only to polymerization and/or decomposition products.