Fruitful interplay between theory and experiment in the design of circularly polarized luminescent materials†
Abstract
Preliminary computations of NBN-benzo[f,g]tetracene/BINOL tethered structures (R)-/(S)-1 and (R)-/(S)-2 that suggest high oscillator strengths f and dissymmetry factors for CPL glum incited us to synthesize these compounds. The optical transitions within these structures have strong charge-transfer character from the benzotetracene-localized HOMOs to the LUMOs located at the BINOL. Large Stokes shifts of around 3500 cm−1 are observed alongside quantum yields of 53–64%. The absorption and luminescence dissymmetry factors from ECD and CPL spectra were measured as gabs = ±0.7 × 10−3 (1) and ±1.0 × 10−3 (2), and glum = ±0.5–0.6 × 10−3 (1) and ±1.6 × 10−3 (2), resulting in a CPL brightness (BCPL) of 12.7–15.1 M−1 cm−1. This work shows that computational screening of chiroptical properties prior to synthesis is useful for identification of suitable materials.