Alkyl length dependent mechanofluorochromism of AIE-based phenothiazinyl fluorophenyl acrylonitrile derivatives

Abstract

Four alkyl phenothiazinyl fluorophenyl acrylonitrile derivatives (PhC3F, PhC6F, PhC10F, and PhC12F) with different length of alkyl chains were synthesized in high yield. The compounds showed obvious aggregation-induced emission (AIE) and alkyl length dependent mechanofluorochromic (MFC) properties. PhC3F with propyl chain and PhC12F with dodecyl chain showed obvious and reversible MFC behaviours, while PhC6F with hexyl chain and PhC10F with decyl chain exhibited little MFC property. Small and wide-angle X-ray scattering indicated the MFC behaviour of PhC3F and PhC12F were attributed to the phase transformation from crystalline to amorphous state, while PhC6F maintained excellent crystalline performance before and after grinding, which was also evidenced by differential scanning calorimetry result. Quantum mechanical computations further revealed PhC6F had high molecular polarity, which greatly improved its crystalline performance, and made its original aggregated morphology hard to damage, then brought about little MFC diversification. PhC10F showed the highest molecular polarity and least MFC behaviour. We concluded that obvious MFC feature derived from appropriate crystalline performance, favourable molecular polarity and energy gap.

Reversible Red‐/Blue‐Shifted Mechanofluorochromic Properties of Indole‐Based Difluoroboron Compounds with Aggregation‐Induced Emission

“…The dipole moments of IÀ PhÀ BF 2 and IÀ PhNpÀ BF 2 were 7.02 D and 7.52 D in the ground state, respectively, indicating that IÀ PhNpÀ BF 2 had a higher molecular polarity and a better crystalline property, it made that the aggregated state was difficult to damage according to the previous reported. [35] This was also confirmed by the XRD test results, thus, the solid powder of IÀ PhNpÀ BF 2 had poor emission displacement after grinding. Nevertheless, the dipole moments of IÀ PhÀ BF 2 and IÀ PhNpÀ BF 2 were 7.60 and 7.49 D in the excited state, respectively.…”

“…Generally, the charges could transfer from the electron donor group to the electron acceptor unit. The dipole moments of I−Ph−BF 2 and I−PhNp−BF 2 were 7.02 D and 7.52 D in the ground state, respectively, indicating that I−PhNp−BF 2 had a higher molecular polarity and a better crystalline property, it made that the aggregated state was difficult to damage according to the previous reported [35] . This was also confirmed by the XRD test results, thus, the solid powder of I−PhNp−BF 2 had poor emission displacement after grinding.…”

Design and Synthesis of AIE-Based Small-Molecule and Nanofibrous Film for Fluorescent Sensing Application

“…Solid-state TPEBZMZ changes from yellow-green to orangeyellow after being mechanically stimulated. We speculate that the reason is the change in the aggregation state of the TPEBZMZ molecules due to the action of external mechanical forces (Ma et al, 2016;Ma et al, 2017). Accordingly, the aggregate structures of the TPEBZMZ powder with different treatments were investigated by powder X-ray diffraction (PXRD) measurements.…”

Multi‐Stimuli Response Displaying Novel Phenothiazine‐Based Non‐Planar D‐π‐A Hydrazones: Synthesis, Characterization, Photophysical and Thermal studies

“…Thus non‐planar D‐π‐A molecules are potential candidates for multi‐stimuli response displaying materials. In this regard, phenothiazine (PTZ) with a twisted bowl‐shaped conformation has proved to be an excellent building block for AIEE as well as MFC active molecules , . Recently, a multi‐stimuli responsive D‐π‐A molecule based on phenothiazine and benzothiazole has been reported which showed mechanoflurochromism as well as acid/base fluorescence switching behavior …”