Perhalophenyl Three-Coordinate Gold(I) Complexes as TADF Emitters: A Photophysical Study from Experimental and...

Area of Science:

• Organometallic Chemistry
• Photophysics
• Materials Science

Background:

• Three-coordinated gold(I) complexes are of interest due to their unique electronic structures and potential applications in luminescence.
• Perhalophenyl ligands can significantly influence the properties of gold complexes.
• Understanding the relationship between molecular structure and photophysical properties is crucial for designing new luminescent materials.

Purpose of the Study:

• To synthesize novel perhalophenyl-gold(I) complexes using 1,2-bis(diphenylphosphino)benzene (dppBz) as a chelating ligand.
• To investigate the solid-state structures and photophysical properties of these complexes.
• To elucidate the emission mechanisms, including phosphorescence and thermally activated delayed fluorescence (TADF), and correlate them with structural features.

Main Methods:

• Synthesis of three-coordinated gold(I) complexes [AuR(dppBz)] (R = C6F5, C6Cl2F3, C6Cl5).
• X-ray crystallography to determine the solid-state structures of complexes 2 and 3.
• Photoluminescence spectroscopy to study emission properties at various temperatures (77 K and room temperature).
• First-principle calculations to analyze photophysical processes like intersystem crossing (ISC) and reverse intersystem crossing (RISC).

Main Results:

• Successful synthesis of three novel perhalophenyl-gold(I) complexes.
• Solid-state structures reveal discrete three-coordinated Au(I) centers with distorted trigonal planar geometry and dissimilar Au-P bond lengths.
• Intense solid-state emissions observed at both 77 K and room temperature.
• Emission behavior transitions from phosphorescence at 77 K to thermally activated delayed fluorescence (TADF) at room temperature.
• Calculated rate constants for ISC and RISC show excellent agreement with experimental observations.

Conclusions:

• The synthesized perhalophenyl-gold(I) complexes exhibit unique structural distortions that are directly related to their photophysical properties.
• These complexes are promising candidates for applications requiring efficient luminescence, displaying both phosphorescence and TADF.
• The study provides valuable insights into the structure-property relationships governing the photoluminescence of three-coordinated gold(I) complexes.