Structures of medium-sized ruthenium clusters: the octahedral motif

Area of Science:

• Inorganic Chemistry
• Materials Science
• Physical Chemistry

Background:

• Understanding the structure of metal clusters is crucial for catalysis and materials science.
• Medium-sized clusters present unique structural and electronic properties.
• Direct structural characterization of these species remains challenging.

Purpose of the Study:

• To determine the precise atomic structures of medium-sized ruthenium clusters (Ru19-, Ru28-, Ru38-, and Ru44-).
• To investigate the relationship between cluster size, geometry, and electronic structure.
• To provide experimental validation for theoretical predictions.

Main Methods:

• Direct structural characterization using trapped ion electron diffraction.
• Computational analysis employing density functional theory (DFT).
• Synergistic application of experimental and theoretical techniques.

Main Results:

• First direct structural characterization of Ru19-, Ru28-, Ru38-, and Ru44- clusters.
• Identification of close-packed structures based on octahedral geometries.
• Ru19- and Ru44- exhibit closed-shell octahedra; Ru28- forms a double octahedron.
• Evidence for lower symmetry structures with reentrant surfaces in Ru38-.

Conclusions:

• Medium-sized ruthenium clusters adopt well-defined, close-packed octahedral structures.
• The electronic shell closing influences the observed geometries.
• Ru38- presents an unusual structural motif deviating from idealized truncated octahedra, highlighting unique surface properties.