Design and functionalization of bixbyite-like In12-Oxo clusters for enhanced optical limiting

Indium-oxo clusters (InOCs) represent a relatively underexplored class within metal-oxo cluster chemistry, with limited research on their core structures, functional modifications, and performance characteristics. In this study, we introduce eight distinct aliphatic and aromatic carboxylate ligands into bixbyite-like In₁₂-oxo clusters (InOC-7 to InOC-14), utilizing the labile substitution sites on the robust In₁₂ skeleton. This ligand incorporation enhances electronic delocalization, narrows the bandgap, and promotes extensive intermolecular π-π interactions. Building upon these structural features and heavy metal effects, the optical limiting (OL) properties of these clusters were systematically investigated. The clusters exhibit characteristic reverse saturable absorption (RSA) behavior, with InOC-8 and InOC-12 demonstrating particularly outstanding OL performance. The excellent optical limiting properties of these crystalline InOCs make them highly relevant to the Journal of Solid State Chemistry, which focuses on the properties and applications of solid materials. This study highlights the scientific value of functionalizing InOCs through labile sites, enriching their structural chemistry, fine-tuning their optical limiting properties, and opening new avenues for potential applications.