Blue highly fluorescent boron difluoride complexes based on phthalazine–pyridine

Abstract

Three new boron difluoride complexes based on phthalazine–pyridine, denoted (6), (7) and (8), have been synthesized and their photophysical and electrochemical properties have been studied. Solutions of these new BF₂-complexes exhibit an intense blue fluorescence under UV light at low concentrations. Fluorescence quantum yields (QYs) have been determined by photoluminescence (PL) spectroscopy and decay times (τ) by semi-empirical methods. QYs of (6), (7) and (8) vary from 25% to 79%. HOMO and LUMO energy levels have been estimated by cyclic voltammetry and PL spectroscopy. The HOMO and LUMO energy levels, at ∼−5.3 eV and ∼−2.3 eV, respectively, make these new complexes interesting candidates as blue emitters in OLED applications.