A Single-Benzene-Based Fluorophore: Optical Waveguiding in the Crystal Form

A single-benzene-based, blue-emissive diethyl 2,5-dihydroxyterephthalate (DDT) was prepared by Fischer esterification of 2,5-dihydroxyterephthalic acid (DHT) and ethanol. The strong fluorescence in both the solution and the solid state from such a simple framework stemmed from the push-pull structure of the electron-donating hydroxy groups and the accepting carbonyl groups, as well as structural planarity from intramolecular hydrogen bonds. The strong intermolecular hydrogen bonds enabled DDT to crystallize easily. The color CCD imaging technique showed efficient 1D optical waveguiding with a large optical loss coefficient of 0.15 dB/μm. DDT has potential application in optical sensors, photonic devices, and optoelectronic communication, because of its highly ordered structure and light-emitting ability.