Chemically reversible isomerization of inorganic clusters

TL;DR

This study demonstrates a reversible isomerization process in inorganic CdS clusters, revealing insights into solid-solid transformations and molecular isomerizations at the atomic scale.

Contribution

It introduces a well-defined inorganic cluster system to study reversible isomerization, bridging molecular and solid-state transformation concepts.

Findings

Clusters interconvert with a 1 eV energy barrier

Displacive reconfiguration of the inorganic core observed

Surface hydroxyl groups influence phase stability

Abstract

Structural transformations in molecules and solids have generally been studied in isolation, while intermediate systems have eluded characterization. We show that a pair of CdS cluster isomers provides an advantageous experimental platform to study isomerization in well-defined atomically precise systems. The clusters coherently interconvert over an est. 1 eV energy barrier with a 140 meV shift in their excitonic energy gaps. There is a diffusionless, displacive reconfiguration of the inorganic core (solid-solid transformation) with first order (isomerization-like) transformation kinetics. Driven by a distortion of the ligand binding motifs, the presence of hydroxyl species changes the surface energy via physisorption, which determines phase stability in this system. This reaction possesses essential characteristics of both solid-solid transformations and molecular isomerizations, and bridges these disparate length scales.