A combinatorial coordination-modulated approach to all-hydrocarbon-ligated intermetallic clusters

Area of Science:

• Organometallic Chemistry
• Cluster Synthesis
• Materials Science

Background:

• Hume-Rothery rules guide the formation of intermetallic compounds.
• Nickel (Ni) and main group element (E) clusters offer unique catalytic and electronic properties.
• Controlling cluster nucleation and growth is crucial for selective synthesis.

Purpose of the Study:

• To investigate the formation of Hume-Rothery-inspired intermetallic and all-hydrocarbon-ligated Ni/E clusters (E = Al, Ga).
• To explore the reactivity of 3-hexyne (hex) with Ni/E species.
• To achieve cluster size-focusing and selective synthesis of novel Ni/E clusters.

Main Methods:

• Reaction of bis(1,5-cyclooctadiene)nickel(0) ([Ni(cod)₂]) with aluminum (Al) or gallium (Ga) cyclopentadienyl (Cp*) precursors in the presence of 3-hexyne (hex).
• Formation of a library of organometallic complexes and small clusters.
• Mass spectrometric monitoring of reaction solutions to analyze cluster formation and growth.

Main Results:

• Successful synthesis of organometallic complexes and small clusters.
• 3-hexyne (hex) reversibly coordinates side-on to Ni/Ga species.
• 3-hexyne (hex) dimerizes at Ni/Al species, indicating different reactivity pathways.
• Demonstrated control over cluster nucleation and growth using a combinatorial, coordination-modulated approach.
• Selective synthesis of specific clusters, such as [Ni₄Ga₄](Cp*)₄(hex)₂, was achieved.

Conclusions:

• The study successfully formed Hume-Rothery-inspired Ni/E clusters.
• The distinct reactivity of 3-hexyne with Ni/Al and Ni/Ga systems allows for controlled synthesis.
• The combinatorial approach provides a pathway for size-focusing and selective synthesis of complex clusters.