Taming and Tuning Multistate Fluorophores for White-Light Emitting Materials

Contained is work conducted for the purposes of creating a single molecule white-light emitter. The efforts include the synthesis and characterization of a number of multistate fluorophores that can either undergo an Excited-State Intramolecular Proton Transfer (ESIPT) or a Charge-Transfer (CT) emission mechanism. In addition, all title compounds studied were sensitive to basic species and generated phenolate like species with distinct emission profiles from their parent phenol like forms. To fully understand the fluorophores of the 2-(2-hydroxyphenyl)benzoxazole (HBO) and 1,4-substituted-1,2,3-trazole varieties, and their potential in a material applications visual spectroscopy was employed (UV-vis, fluorescence, quantum yield, and CIE 1931 coordinates). The results for dyes derived from the 1,4-substituted-1,2,3-triazole structures were found to contain interesting CT behavior and photo switching upon addition of base but were shown to lack an emissive ESIPT mechanism. Dyes derived from the HBO structures contained significant solvatochromic shifts from ~420 nm (blue) to ~550 nm (yellow) in the neutral forms. Quantum yields were found up to 0.35 and CIE 1931 coordinates close to the value for ideal white-light with values at around (0.31, 0.32). The phenolate derivatives were found to be mostly monochromatic with high quantum yields from 0.20–0.80