New Two-Photon Absorbing Fluorene Derivatives: Synthesis and Nonlinear Optical Characterization

Abstract

Efficient Pd-catalyzed Heck coupling methodology was employed to provide two new fluorene derivatives with phosphonate (2) and nitro (3) electron-withdrawing functionalities. Both derivatives exhibit two-photon absorption (2PA), as determined by nonlinear absorption measurements using a femtosecond pump/white light continuum probe “NLO spectrometer”. Both fluorene derivatives have high 2PA cross sections (650 and 1300 × 10-50 cm4 s photon-1 molecule-1 for compounds 2 and 3, respectively).