Macroscalar Helices Co-Assembled from Chirality-Transferring Temperature-Responsive Carbohydrate-Based Bolaamphiphiles and 1,4-Benzenediboronic Acid

Abstract

We present the first example of macroscalar helices co-assembled from temperature-responsive carbohydrate-based bolaamphiphiles (CHO-Bolas) and 1,4-benzenediboronic acid (BDBA). The CHO-Bolas contained hydrophilic glucose or mannose moieties and a hydrophobic coumarin dimer. They showed temperature-responsive reversible micelle-to-vesicle transition (MVT) in aqueous solutions. After the binding of carbohydrate moieties with boronic acids of BDBA in their alkaline solutions, right-handed helices were formed via the temperature-driven chirality transfer of d-glucose or d-mannose from the molecular to supramolecular level. These helices were co-assembled by unreacted BDBA, boronate esters (B−O−C bonds) between CHO-Bolas and BDBA, as well as boroxine anhydrides (B−O−B bonds) of self-condensed BDBA. After heating at 300 °C under nitrogen, the helices displayed excellent morphological stability. Moreover, they emitted bright blue luminescence caused by strong self-condensation of BDBA and decomposition of coumarin dimers.