Near-Infrared Electrochromic and Chiroptical Switching Materials: Design, Synthesis, and Characterization of Chiral Organogels Containing Stacked Naphthalene Diimide Chromophores

Chiroptical switching materials in the visible and near-infrared spectral regions have been realized using a low molecular weight gel as a chiral scaffold and electrochromic chromophores as a stimulus-responsive trigger and operate as a result of the change in the electronic states of the chromophores within the chiral gel. N, N ′-Bis(4-phenyl-2,3,4,6-tetra- O -acetyl-β- d -glucopyranoside)-1,4,5,8-naphthalenetetracarboxylic diimide, synthesized by imidization of 1,4,5,8-naphthalenetetracarboxylic dianhydride with a sugar-bearing amine, can form stable chiral gels at room temperature. The redox-active gels exhibited reversible and drastic changes in circular dichroism in the visible and near-infrared spectral region between the three redox states (neutral, radical anion, dianion) of the naphthalene diimide chromophore. A large circular dichroism at 1310−1550 nm was induced when the stacked naphthalene diimide chromophores in the chiral gels were reduced to the radical anion state.