Red-Colored Circularly Polarized Luminescence from a Benzo-Fused BODIPY-BINOL Complex

Abstract

Red emission with sharp bandwidth and high quantum yield is a desired characteristic for organic chromophores in optoelectronic, spintronic, and biomedical applications. Here, we observe circularly polarized luminescence (CPL) with these characteristics from a benzo-fused BODIPY-BINOL complex (1). Using time-resolved optical spectroscopy, electrochemistry, and density functional theory calculations, we showed that the emissive excited state of 1 does not have a charge-transfer (CT) character, unlike that of the regular BODIPY counterpart (2). The rigidity and the lack of CT character make this class of molecules an appealing platform for CPL-active molecules in the red spectral region, with ample room for improvement in the dissymmetry factor and brightness.

Pd and Pt Complexes of Benzo-Fused Dipyrrins: Synthesis, Structure, Electrochemical, and Optical Properties

“…In both cases, these intense absorption bands are significantly red-shifted relative to the Pd 2+ complex of regular dipyrrin (λ max = 476 nm) but are close to the reported benzo-fused BODIPY molecules. , …”

“…In both cases, these intense absorption bands are significantly red-shifted relative to the Pd 2+ complex of regular dipyrrin (λ max = 476 nm) 48 but are close to the reported benzo-fused BODIPY molecules. 43,49 We observed very weak room-temperature fluorescence for the Pd(L) 2 complex in acetonitrile and toluene, with λ max = 665 nm. In toluene solution, the quantum yield for this fluorescence was measured to be Φ fl = 0.0038 and fluorescence lifetime τ fl = 0.8 ns.…”

“…Benzo-fused dipyrrins, in which each of two conjugated pyrrole units is fused with the benzene ring, possess a bathochromic shift in absorption spectra due to extended π-conjugation and therefore can be particularly interesting for biomedical ,, and material science applications, such as solar cell technology, , circularly polarized luminescence materials, and optical power limiting (OPL) filters . However, in contrast to regular dipyrrins, there is limited information available regarding complexes of benzo-fused dipyrrins with transition metals.…”