Synthesis and Tunable Optical Properties of C,N-Chelated Borate Luminophores Derived from Potassium Acyltrifluoroborates
A new class of borate luminophores has been synthesized by a simple two‐step reaction using potassium acyltrifluoroborates (KATs) as starting materials. The hydrazones obtained from reactions between KATs and 2‐hydrazinopyridines followed by a cyclization resulted in the unprecedented formation of C,N‐chelated six‐membered bora‐heterocycles. Under consideration of the results of DFT and TD‐DFT calculations, four luminophores based on such bora‐heterocycles are designed and synthesized, which exhibit a tunable fluorescence range from blue to red in the solid state. Moreover, one of the luminophores exhibits mechanofluorochromism from blue to yellow/green. As a result of the aforementioned mechanochromism of one of these luminophores, white‐color emission was achieved by simply mixing the four luminophores.