Diphosphine-Stabilized Small Gold Nanoclusters: From Crystal Structure Determination to Ligation-Driven Symmetry Breaking and Anion Exchange Properties

A new class of small gold nanoclusters with molecular characteristics has been constructed using 1,1'-bis(diphenylphosphino)ferrocene (dppf) as the stabilizing ligand. The identities of the small gold nanoclusters have been fully characterized by NMR, electrospray ionization mass spectrometry, elemental analysis, and single-crystal X-ray diffraction analysis. Octa- and undecagold clusters are found to display different UV-vis absorption behavior. The ligation of the bidentate ligands and halides or pseudohalides has resulted in the symmetry breaking of these nanoclusters with C-1 symmetry. The small gold nanoclusters with different coordinating halides or pseudohalides show distinct reactivities and stabilities in ligand/anion exchange experiments. The current research has provided insights into the origin of chirality in the diphosphine-stabilized small gold nanoclusters.