Highly emissive supramolecular gold(I)-BTD materials.

Area of Science:

• Materials Science
• Inorganic Chemistry
• Photochemistry

Background:

• Gold(I) complexes are investigated for their unique photophysical properties.
• N-heterocyclic carbene ligands offer tunable electronic and steric properties.
• 2,1,3-benzothiadiazole (BTD) derivatives are known for their emissive characteristics.

Purpose of the Study:

• To synthesize and characterize novel light-emitting rod-shaped gold(I) complexes.
• To investigate the effect of N-heterocyclic carbene ligand size on complex structure and intermolecular interactions.
• To explore the photophysical properties, particularly luminescence, in solid-state and polymer matrix environments.

Main Methods:

• Synthesis of three gold(I) complexes by combining ethynyl-functionalized 2,1,3-benzothiadiazole (BTD) with different N-heterocyclic carbene ligands.
• Single crystal X-ray diffraction for structural determination.
• Photoluminescence spectroscopy to study emission properties in solid-state and polymer matrices.

Main Results:

• Successful synthesis of three rod-shaped gold(I) complexes with varying N-heterocyclic carbene ligands.
• Structural analysis revealed ligand-dependent molecular packing and disposition, influencing aurophilic interactions.
• The phenantroimidazole derivative exhibited stronger aurophilic interactions due to a planar ligand conformation.
• Two distinct solid-state emission colors were observed for one complex, attributed to packing variations.
• Incorporation into polymer matrices significantly enhanced luminescence quantum yields, approaching unity.

Conclusions:

• The size and electronic properties of N-heterocyclic carbene ligands critically influence the solid-state structure and luminescence of gold(I) complexes.
• Aurophilic interactions play a key role in modulating emission properties.
• These gold(I) complexes show promise for applications in polymer-based light-emitting devices due to their enhanced emission in polymer matrices.