Fluorescence and photochemical properties of crystalline boron difluoridesbeta-diketonato

The fluorescence and photochemical properties of crystalline beta-diketonat oboron difluorides (DBD) (RCOCHCORBF2)-B-1 were studied. These compounds ar e characterized by relatively high photochemical stability. The introductio n of electron-donating groups into the aromatic alpha-substituent of the ch elate ring increases and the introduction of electron-withdrawing groups de creases the fluorescence intensity of DBD. Anisoylbenzoylmethanotoboron dif luoride was found to exhibit the highest fluorescence intensity. The substi tuents were shown to influence the relative arrangement of singlet and trip ler n pi* and pi pi* levels and luminescence properties of compounds.