Mechanistic Insights into Oxidation-Induced Size Conversion of [Au 6 (dppp) 4 ] 2+ to [Au 8 (dppp) 4 Cl 2 ] 2 .

Oxidation-induced conversion of gold nanoclusters is an important strategy for preparing novel atomically precise clusters and elucidating the kinetic correlations of different clusters. Herein, the oxidation-induced growth from [Au 6 (dppp) 4 ] 2+ to [Au 8 (dppp) 4 Cl 2 ] 2+ (reported by Konishi and co-workers) has been studied by density functional theory calculations. A successive oxidation → Cl - coordination → oxidation → Cl - coordination sequence occurs first to activate the Au 6 structure, resulting in the high Au(core)-Au(corner) bond cleavage activity and the subsequent formation of [Au 2 (dppp) 2 Cl] + and [Au 4 (dppp) 2 Cl] + fragments. Then, the dimerization of two Au 4 fragments and the rearrangement of the diphosphine coordination occur to generate the thermodynamically stable [Au 8 (dppp) 4 Cl 2 ] 2+ products. The proposed mechanism agrees with the experimental outcome for the fast reaction rate and the residual of the Au 2 components. Specifically, a multivariate linear regression analysis indicates the strong correlation of the oxidation potential of Au 6 , Au 8 , Au 23 , and Au 25 clusters with the HOMO energy, the number of Au atoms, and cluster charge state. The main conclusions [e.g., oxidation-induced Au(corner)-Au(core) bond activation, easy 1,2-P transfer steps, etc.] of this study might be widely applicable in improving our understanding of the mechanism of other cluster-conversion reactions.