Glutathione-Coated Au29(SG)27: Structural Determination Based on Different Combination Styles Confirmed by Experiments

Glutathione-coated small-sized gold nanocluster denoted as Au29(SG)27 has potential applications in bio therapeutics. Since it is difficult to obtain an accurate atomic structure experimentally, its structure is predicted by density functional theory. The atomic structure of Au29(SG)27 is speculated to contain a ring motif (for low Au/S ratio), the Au4 core and staple motifs (by “divide and protect” method). In the structural optimization, we proposed the four various combination styles, and took the second and third combinations respectively when N≤6 and N>6 (N is the number of Au atoms in the ring motif). All stable isomers are sorted by energy, and the structure with the lowest energy (isomer 1) consists of Au7(SCH3)7 ring motif and an Au4 core attached staple motifs as Au4Au8(SCH3)9Au10(SCH3)11. Then we calculated and analyzed the atomic and electronic structures of isomer 1. The electronic transition of HOMO-LUMO is mainly the transition from d orbital to p orbital, which is within gold core or betwe...