Self-reversible mechanofluorochromism of AIE-active C6-unsubstituted tetrahydropyrimidine derivatives

• DOI: 10.1039/d0ra09209f
• Publication Date: 2020-12-21T17:15:03Z
• Authors: Yanshan Liu; Yunhui Liao; Ziwei Ye; Lina Chen; Yun He; Yifan Huang; Yingyu Lai; Junguo Chen; Qiuhua Zhu
• Keywords: Chemistry; 13. Climate action; 01 natural sciences; 0104 chemical sciences; 3. Good health

The mechanofluorochromic properties of three C6-unsubstituted tetrahydropyrimidines (THPs), namely, diethyl 1,2,3-triphenyl-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylate (1), dimethyl 1,2,3-tri(4-trifluoromethylphenyl)-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylate (2), and 1,2,3-tri(3-trifluoromethylphenyl)-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylate (3), with aggregation-induced emission (AIE) characteristics were investigated. blue-green/cyan emissions the THPs can be switched reversibly by a grinding-fuming/heating process, change in maximum wavelength (λ em) up to 57 nm decrease fluorescence quantum yields (Φ F). Interestingly, green or cyan ground powder em is located at 481, 470 477 for 1b, 2 3, respectively) spontaneously recover original blue 434, 442 436 1-2 d room temperature without any external stimulation. X-ray single-crystal diffraction, diffraction (XRD) differential scanning calorimetry (DSC) studies demonstrate that conversion between molecular packing modes main reason mechanofluorochromism recoverable relates intermolecular hydrogen bonds. sensitively and/or these expected have great potential sensing, optical recording self-healing fluorescent materials.