Unlocking Arene Phosphorescence in Bismuth-Organic Materials

Area of Science:

• Materials Science
• Inorganic Chemistry
• Organic Chemistry
• Luminescence

Background:

• Bismuth-organic compounds offer unique structural and electronic properties.
• Understanding structure-property relationships is crucial for designing luminescent materials.
• Coordination complexes with aromatic molecules can exhibit interesting photophysical behaviors.

Purpose of the Study:

• To synthesize and structurally characterize novel bismuth-organic compounds.
• To investigate the luminescent properties of these compounds, focusing on arene-derived emission.
• To explore the potential of these materials in organic light-emitting applications.

Main Methods:

• Synthesis of three novel bismuth-organic compounds: [Bi2(HPDC)2(PDC)2]·(arene)·2H2O.
• Structural characterization using X-ray diffraction to analyze π-π stacking interactions.
• Photoluminescence and radioluminescence measurements under UV irradiation.

Main Results:

• Compounds with pyrene and naphthalene showed red and green phosphorescence, respectively, originating from the arene's T1 → S0 transition.
• Quantum yields for pyrene and naphthalene compounds were 1.3(2)% and 30.8(4)%, respectively.
• The azulene-containing compound exhibited weak blue-purple phosphorescence, a rare T2 → S0 emission from azulene.

Conclusions:

• Strong π-π stacking interactions in the crystal structures influence luminescence properties by restricting molecular vibrations.
• The emission color and efficiency are directly related to the incorporated arene molecule.
• These bismuth-organic compounds demonstrate significant potential for developing novel organic light-emitting materials.