Engineering intermolecular charge transfer in chiral organometallic crystals by rational doping for high-contrast CPL switches

The development of circularly polarized luminescence (CPL) switches is of great importance but challenging. Herein, a charge donor/acceptor pair comprising two chiral gold(I)-isocyanide complexes was designed to construct light-harvesting system via intermolecular charge-transfer (CT) interactions. By doping nonemissive S-AuI into blue-emitting S-AuCN, (S-AuCN)(1-x)(S-AuI)(x) (0 <= x <= 3.4%) with tunable emission from blue to red was achieved. This large red-shifted emission was realized based on the remarkable change of the electronic properties between the S-AuCN dimer and red-emitting (S-AuCN)-(S-AuI) CT pair, and the resulting energy-transfer (EnT) process between them. Importantly, the EnT process can be switched off/on by external stimuli of grinding and CH2Cl2 fuming, giving rise to high-contrast (blue versus red) CPL switching properties. This study opens a novel avenue for developing CPL switches by constructing light-harvesting CT-doped systems based on chiral organometallic complexes.

Automated summary

In this study, a charge donor/acceptor pair was designed to construct a light-harvesting system based on two chiral gold(I)-isocyanide complexes. By doping nonemissive S-AuI into blue-emitting S-AuCN, a tunable emission from blue to red was achieved. This large red-shifted emission was realized through the change in electronic properties and the resulting energy-transfer process between the S-AuCN dimer and red-emitting (S-AuCN)-(S-AuI) CT pair. Importantly, the energy-transfer process can be controlled by external stimuli, leading to high-contrast CPL switching properties. This study opens a new avenue for developing CPL switches using chiral organometallic complexes.