Formation and Reversible Transformation between Two (CdTe)34 Magic-Size Clusters at Room Temperature.

The formation and transformation process of nanomaterials often involves intermediates that are difficult to detect. Consequently, unraveling these dynamic evolution pathways remains a significant challenge. Here, we report the room-temperature evolution of two magic-size cluster (MSC) isomers, MSC-448 and MSC-430, with an identical (CdTe)34 core composition. We show that the conversions from CdTe prenucleation clusters (PNCs) to MSC-448 to MSC-430 are induced by linear primary amines with low steric hindrance. Investigation on the reversed transformation from CdTe MSC-430 to MSC-448 by in situ UV-vis spectroscopic monitoring reveals that their interconversion is not a direct rearrangement. Instead, it proceeds via optically transparent precursor compounds (PCs) via a monomer-assisted process. Kinetic analysis reveals the first-order behavior with a rate constant of 0.025 min-1 and an activation energy of 56.0 kJ·mol-1. We propose that monomer substitution is the rate-determining step. Our findings illustrate the stepwise pathways of CdTe MSC isomerization and highlight the critical roles of ligands and monomers in mediating structural change at the nanoscale.