A Halogen-Bonded Fluorescent Molecular Photoswitch: Transition from 3D Cubic Lattice to 1D Helical Superstructure for Polarization Inversion of Circularly Polarized Luminescence.
Angew Chem Int Ed Engl
; : e202405615, 2024 Jun 10.
Article
em En
| MEDLINE
| ID: mdl-38856204
ABSTRACT
The fabrication of materials that can switch between circularly polarized luminescence (CPL) signals is both essential and challenging. Here, two new halogen-bonded fluorescent molecular photoswitches, namely, HB-switch 1 and HB-switch 2, containing α-cyano-substituted diarylethene compounds with different end groups were developed. Upon exposure to specific UV or visible light wavelengths, they exhibited controllable and reversible Z/E photoisomerization. When these switches were integrated into blue-phase liquid crystals (BPLCs), the temperature range of BP significantly expanded. Notably, the BP system incorporating HB-switch 1 exclusively achieved reversible polarization inversion of CPL signals under irradiation with specific UV/Visible light and during cooling/heating. The photo/thermal dual-response behavior of the CPL signals can be attributed to the phase transition from a high-symmetry 3D BP Icubic lattice to a low-symmetry 1D helical superstructure induced by the Z/E photoisomerization of HB-switch 1 and temperature changes. This study underscores the significance of employing halogen-bond assembly strategies to design materials with switchable CPL signals, opening new possibilities for CPL-active systems.
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MEDLINE
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En
Ano de publicação:
2024
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Article