Multistimuli-Responsive Copper(I) Complexes Exhibiting Thermally Activated Delayed Fluorescence

Area of Science:

• Materials Science
• Photochemistry
• Coordination Chemistry

Background:

• Multistimuli-responsive luminescence is crucial for advanced optical materials.
• Copper(I) complexes offer potential for efficient luminescence and stimuli-responsiveness.

Purpose of the Study:

• To synthesize and characterize novel Cu(I) heteroleptic complexes with distinct N-heterocyclic fragments.
• To investigate the multistimuli-responsive luminescence and thermally activated delayed fluorescence (TADF) properties of these complexes.
• To explore structure-property relationships for tuning luminescence characteristics.

Main Methods:

• Synthesis of two Cu(I) heteroleptic complexes (1 and 2) with pyrazinyl and pyridyl ligands.
• Characterization of luminescence properties under various stimuli (grinding, heating, solvent vapor).
• Structural analysis using single-crystal and powder X-ray diffraction, and Fourier-transform infrared (FT-IR) spectroscopy.

Main Results:

• Both complexes demonstrated reversible multistimuli-responsive luminescence and TADF.
• The luminescence switching mechanism was attributed to the reversible breaking and formation of NH···O hydrogen bonds.
• Luminescent color and contrast were modulated by structural modifications, such as N-atom incorporation in the pyridyl ring.

Conclusions:

• The study successfully designed Cu(I) complexes with tunable multistimuli-responsive luminescence.
• Rational modification of diimine heterocyclic skeletons is key for developing low-cost luminescent materials with adjustable optical properties.
• These findings provide valuable insights for the design of advanced responsive luminescent materials.