Robust Light-Emitting Gold(I) Complexes

Robust Light-Emitting Gold(I) Complexes

Author: Angewandte Chemie International Edition

Gold(I) complexes can have interesting luminescent properties. However, they are rarely used in organic light-emitting diodes (OLEDs) because the typical linear two-coordinate structure of gold(I) complexes lacks stability.

Kai Li,  Chuluo Yang, Shenzhen University, China, and colleagues have developed a new class of robust gold(I) complexes with thermally activated delayed fluorescence (TADF) properties. The researchers first carried out a palladium-catalyzed borylation of a carbazole derivative. The resulting product was then reacted with a gold precursor complex of the type NHC–Au–Cl (NHC = N-heterocyclic carbene) to form gold(I) complexes (IPzIDCz, pictured below).

The rigid aryl ligand and the twisted orientation of the carbene ligand force the gold nucleus into a “groove” stabilized by nonvalent Au···H hydrogen bonds. The structure was verified using single-crystal structure analysis and NMR spectroscopy.

In an organic host material, the IPzIDCz gold(I) complex demonstrated a high emission efficiency of 76 %, a short delayed fluorescence lifetime of 1.2 µs, and good thermal and photostability. Vacuum-deposited OLEDs containing the complex show promising properties with a maximum external quantum efficiency (EQE) of over 23 % and good operational stability. The work provides a path to robust mononuclear gold(I) emitters, which may have an impact on the future design of luminescent transition-metal complexes.


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