The synthesis of −1, −3, −5, −7, −8 aryl substituted boron-dipyrromethene chromophores: Nonlinear optical and photophysical characterization

Abstract

A convenient protocol enabled the synthesis of novel Arylated Borondipyrromethene (BODIPY) compounds was applied that synthesis yields found to be higher than classical alkyl substituted analogues. The nonlinear properties of the target molecules were investigated systematically in terms of aryl substitution to the pyrrole side and the meso substitution on the indacene core. It was found that, −3, −5 positions of the indacene core are effective positions for charge transfer, which is essential for two photon absorption (TPA). The greatest two photon cross section (TPCS) value (178 GM) is obtained for BDP3 compound, while TPCS value of BDP4 compound is 27 GM at near infrared wavelength (800 nm). Arylated chromophores exhibited the broader red-shifted absorption and fluorescence bands with higher stokes shifts with regard to reference Borondipyrromethene compound (4,4′-difluoro-8-phenyl-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene, TMB). Our results are helpful for designing new photosensitizers and for applications in the study of the molecular photochemistry.