Hydrogen Bonding–Induced Multicolor and Thermochromic Emissions of Triphenylamines

Abstract The fluorescence tuning of stimuli‐responsive materials is crucial but challenging. The deep understanding of thermal induced fluorescence change, however, has rarely been conducted. Herein, the thermochromic emission of a triphenylamine (TPA) derivative ( 1 ), with one acetyl and two 1‐hydroxy‐1‐methylethyl units on each o ‐phenyl group around the nitrogen atom, has been investigated. Upon heating, the bright blue‐emitting solid 1 turns to a strong green‐emitting liquid. Moreover, 1 is green emissive in ethanol but blue emissive with high absolute quantum yields in dimethyl sulfoxide (DMSO). Another TPA derivative ( 2 ) is green emitting. X‐ray crystallography studies reveal that the strong solid‐state fluorescence arises from a rigid pyramidal structure around central nitrogen of 1 , due to the OH•••OH, OH•••O = C hydrogen bonding interactions. Comparatively, 2 has a planar configuration of three C─N bonds around central nitrogen atom. This work will provide a new route for constructing multiemission materials using unimolecular platforms.