2026 Theses Doctoral

Structure-Property Relationships in Superatomic Solids

Okuno, Saya Catharine

This work describes the use of primarily solution-phase techniques to synthesize and modify superatomic materials to study the ways that structure influences properties.

The first chapter acts as background and introduction for the entire thesis, detailing the history and scope of superatomic materials in, and in particular superatomic metal-chalcogenide based materials.

In the second chapter I will describe how functionalization methods to replace surface ligands on Re₆Se₈Cl₂ can be used to append catalytically active groups on the surface of the material, as well as attempts to cross-link the 2-dimensional sheets with various linker groups. Characterization techniques like high-resolution scanning tunneling electron microscopy and scanning electron microscopy energy dispersive spectroscopy confirm that the in-plane structure of the material is intact post-reaction, and that there is high coverage of the target molecule on the surface. Electrochemical characterization shows how the Re₆Se₈ sheets with anchored cobalt catalysts perform oxygen evolution reaction catalysis with appreciable performance.

In the third chapter I will describe the structure and characterization of novel materials comprised of Co₆Se₈ clusters and C₆₀. In the first section of chapter 3 I will show how we can extend the Torrance framework for donor-acceptor (D-A) charge-transfer solids to superatomic cluster-fullerene lattices and use it to design [Co₆Se₈(PEt₂(S)-methylbutyl)₆]₄[C₆₀]₆·6C₅H₈ (2), a material poised at an ionic-neutral electronic boundary. Compound 2 exhibits an inverted ionic to neutral valence tautomeric transition upon cooling, revealed through multimodal spectroscopy and electronic structure calculations. The second section of chapter 3 details work to synthesize and characterize a variety of novel Co6Se8 clusters with 𝜂2 bonded ligands.