Mechanofluorochromism of D-A typed phenothiazine derivative

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2018-06, Vol.361, p.112-116
• Main Authors: Jia, Junhui, Zhang, Huijuan
• Format: Article
• Language: English
• Subjects: Chemical synthesis; D-A typed; Dichloromethane; Emission; Fluorescence; Friedel-Crafts reaction; Grinding; Heating; ICT; Mechanofluorochromism; Molecular structure; Phase transitions; Phenothiazine; Solid solutions; Solid state physics
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2018.05.012

[Display omitted] •A phenothiazine derivative (MPTPM) containing two benzoyl groups.•MPTPM was a D-A typed molecule.•MPTPM showed reversible mechanofluorochromic nature.•Mechanofluorochromic nature was generated through crystalline-amorphous phase transformation under external pressure. A D-A typed phenothiazine derivative MPTPM has been designed and synthesized via a Friedel-Crafts reaction, which contains two benzoyl groups. It was found that MPTPM gave strong emission in solution and in solid state, and the solid fluorescence quantum yield was as high as 0.60. Moreover, an excellent reversible mechanofluorochromic behavior was realized upon the treatment of grinding/fuming with CH2Cl2 or heating in spite of a very simple molecular structure. The emission color of MPTPM changed from green to orange-yellow after grinding and could be restored via fuming with CH2Cl2 or heating with a spectra shift of ∼63 nm. Photophysical, XRD, DSC studies indicated the mechanofluorochromic properties of MPTPM originating from the transformation between crystalline phase and amorphous phase.