Affiliation:
1. Yunnan Key Laboratory of Metal‐Organic Molecular Materials and Device, School of Chemistry and Chemical Engineering Kunming University Kunming P.R. China
2. Chromatographic Analysis Center Dali Institute for Food Control Dali P.R. China
3. Physical and Chemical Inspection Center Dali Institute for Food Control Dali P.R. China
Abstract
AbstractTo further explore the relationship between aryl substituents and mechanofluorochromic (MFC) behaviors, four salicylaldimine‐based difluoroboron complexes (ts‐Ph BF2, ts‐Ph‐NA BF2, ts‐2NA BF2, and ts‐triphenylamine [TPA] BF2), including aromatic substituents with different steric hindrance effects, were designed and successfully synthesized. Four complexes with twisted molecular conformation displayed intramolecular charge transfer and aggregation‐induced emission properties. Under external mechanical stimuli, the as‐synthesized powders of ts‐Ph BF2, ts‐Ph‐NA BF2, and ts‐TPA BF2 exhibited redshift fluorescence emission behaviors, and ts‐Ph BF2 and ts‐TPA BF2 could be recovered to original shifts by fuming, but ts‐Ph‐NA BF2 displayed irreversible switching. ts‐2NA BF2 had no change during the grinding and fuming processes. The results indicated that the MFC behaviors could be attributed to the phase transformation between the well‐defined crystalline and disordered amorphous states by X‐ray diffraction measurement. Further research illustrated that ts‐TPA BF2 with the most significant MFC phenomenon could be applied in data security protection in ink‐free rewritable paper.