Pyrene-based color-tunable dipolar molecules: Synthesis, characterization and optical properties

Abstract

A controllable regioselective approach to achieve dipolar functionalization at the active sites (1,3-positions) and K-region (5,9-positions) of pyrene is demonstrated. Following this strategy, a set of dipolar 1,3-diphenyl-5,9-di(4-R-phenylethynyl)pyrenes were synthesized and systematically investigated by 1H/13C NMR spectroscopy, X-ray crystallography, electronic spectra, as well as by theoretical calculations. By adjusting the substituents at the 5,9-positions of pyrene, the pyrene-based dipolar molecules 4 (H, F, OMe, CN, CHO, NMe2) exhibit tunable optical properties with a wide emission band from blue (437 nm) to orange-red (571 nm).