Monosaccharide-Based Deep Eutectic Solvents for Developing Circularly Polarized Luminescent Materials

Abstract

Deep eutectic solvents (DES) with chiral components can function as solvents in circularly polarized light-emitting materials. Deep eutectic solvents were developed with chiral hydrogen bond donors derived from biomass, glucose, and fructose, combined with tetrabutylammonium chloride ([TBA]Cl) as the hydrogen bond acceptor. Physical properties, such as density, melting points, relative polarity, and polarimetry, were measured for the monosaccharide-based DES. The impact of the [TBA]Cl:glucose ratio on the relative polarity is described. A racemic mixture of dissymmetric europium and terbium complexes is dissolved in the monosaccharide-based DES to measure the resulting chiral discrimination and induced circularly polarized luminescence (CPL). The samples showed red (Eu3+) and green (Tb3+) CPL with a sign that is controlled by the enantiomer (L vs D) of monosaccharide. Results from the glucose DES showed that the polarity of the DES and the anomeric form of the monosaccharide is important to the magnitude of induced CPL.