Tetragold(I) complexes: solution isomerization and tunable solid-state luminescence

Area of Science:

• Inorganic Chemistry
• Materials Science
• Photochemistry

Background:

• Gold(I) complexes are known for their luminescent properties.
• Tetranuclear gold clusters offer unique structural and electronic characteristics.
• Developing new materials for organic light-emitting diodes (OLEDs) is an active area of research.

Purpose of the Study:

• To synthesize and characterize novel tetranuclear gold(I) triphosphine derivatives.
• To investigate the photophysical properties, specifically photoemission, of these gold clusters.
• To evaluate the potential of these compounds as emissive materials in OLED devices.

Main Methods:

• Sequential synthesis involving polymeric acetylides or thiolates, phosphine ligands, and cationic gold complexes.
• Characterization using X-ray crystallography and Nuclear Magnetic Resonance (NMR) spectroscopy.
• Photoluminescence spectroscopy and quantum chemical density functional theory (DFT) calculations.
• Fabrication and testing of an organic light-emitting diode (OLED) device.

Main Results:

• Efficient synthesis of a new family of tetranuclear gold(I) clusters ([Au4(P^P^P)2(C2R)2](2+) and [Au4(P^P^P)2(SPh)2](2+)).
• Solid-state structures confirmed by X-ray crystallography; solution NMR revealed isomeric equilibria.
• Moderate-to-strong photoemission observed with quantum yields up to 0.51.
• Successful fabrication of an OLED using complex 5, demonstrating good external quantum efficiency (3.1%).

Conclusions:

• The synthesized tetranuclear gold(I) compounds are promising emissive materials.
• Their luminescence properties are tunable and can be rationalized by DFT.
• These gold clusters show potential for application in solution-processed OLEDs with competitive performance metrics.