Gold(I) alkoxide and thiolate complexes as potential atomic layer deposition precursors

Area of Science:

• Organometallic Chemistry
• Materials Science
• Chemical Synthesis

Background:

• Gold(I) complexes are investigated for their unique electronic properties and potential applications in catalysis and materials science.
• The development of thermally stable and volatile gold precursors is crucial for techniques like atomic layer deposition (ALD).

Purpose of the Study:

• To synthesize and characterize novel gold(I) alkoxide and thiolate complexes.
• To evaluate the thermal stability, volatility, and reactivity of these complexes for potential use as precursors in ALD.

Main Methods:

• Synthesis of gold(I) alkoxide complexes [(Au{OC(CF3)3}{PR3})n] via reaction of AuCl(PR3) with NaOC(CF3)3 and silver salts.
• Synthesis of gold(I) thiolate complexes [{Au(StBu)(PR3)}n] from [{Au(StBu)}n] and PR3.
• Characterization using techniques including solid-state structural analysis, melting point determination, sublimation, and reactivity studies with HBpin and H3SiPh.

Main Results:

• Gold(I) alkoxide complexes [(Au{OC(CF3)3}{PR3})n] were successfully synthesized, with structural diversity (trimer to monomer) depending on steric hindrance.
• Thiolate complexes [{Au(StBu)(PR3)}n] were also prepared, exhibiting different aggregation states (dimer to monomer).
• Complex 3, an alkoxide, showed promising thermal stability and volatility, enabling gold deposition via ALD at 124 °C in the presence of HBpin, unlike the thiolate complex 5.

Conclusions:

• The steric bulk of the phosphine ligand significantly influences the solid-state structure of gold(I) alkoxide complexes.
• Gold(I) alkoxide complexes exhibit faster reactivity towards reductive decomposition compared to thiolate complexes.
• The gold(I) alkoxide complex 3 presents a viable precursor for ALD of gold, offering a balance of stability and volatility.