Superatomic Three-Center Bond in a Tri-Icosahedral Au36Ag2(SR)18 Cluster: Analogue of 3c-2e Bond in Molecules

Probing the nature of electronic stability for ligand-protected gold clusters is important in gold chemistry. A thermally stable Au36Ag2(SR)(18) nanocluster was synthesized recently. It has a D-3h tri-icosahedral [Au30Ag2](12+) core with 20 valence electrons, which does not follow the magic number of gold superatoms. Herein, we propose a superatomic three-center bond to unveil its electronic stability. The [Au30Ag2](12+) core is viewed as a union of three face-fused superatoms, and chemical bonding analysis suggests a three-superatom-center two-electron (3sc-2e) bond for the octet rule of each superatom, which mimics the bonding framework of the D-3h O-3(2-) molecule. Moreover, a liganded tri-icosahedral [Au27Pt3Ag2](11+) core with 18 valence electrons is predicted, and three 2sc-2e bonds are formed between each of two superatoms to satisfy the octet rule (analogue of D-3h O-3), indicating the flexibility of superatomic bonding. Such a superatomic three-center bond extends the community of superatomic bonding and gives a new perspective for superatom assembling.

Automated summary

Probing the nature of electronic stability for ligand-protected gold clusters is important in gold chemistry. A recent synthesis of a thermally stable Au36Ag2(SR)(18) nanocluster revealed its electronic stability through a superatomic three-center bond, expanding the understanding of superatomic bonding.