Large steric hindrance amide modified benzothiadiazole: High contrast mechanochromic luminescence and volatile acid vapor response

• Key Words:FLUORESCENCE; TRIPHENYLAMINE; EMISSION
• Abstract:Three mechanochromic luminescent (MCL) materials were obtained by modifying the 5, 6 and 4, 7 positions of benzothiadiazole (BTD) with two sterically hindered amides and two aromatic groups, respectively. The Stokes shifts of the compounds were larger in different solvents (> 6000 cm(-1)), especially 3c in dimethyl sulfoxide up to 8900 cm-1. Upon response to mechanical force, the fluorescence of 3c had high contrast (75 nm) before and after milling, and the emission changed from bright yellow light (533 nm) to orange-red light (608 nm). Meanwhile, strong fluorescence emission intensities were observed before and after grinding (quantum yield: 56%, 46% respectively). The MCL reasons of the compounds were explained in detail by theoretical calculation, single crystal X-ray diffraction (XRD), powder XRD and differential scanning calorimetry (DSC) analysis. In addition, the MCL materials also showed fluorescence responsiveness to the vapor of volatile acids.
• Volume:204
• Issue:
• Translation or Not:no