Crystal Structure of the Gold Nanoparticle [N(C8H17)4][Au25(SCH2CH2Ph)18]

Abstract

We report the crystal structure of the thiolate gold nanoparticle [TOA⁺][Au₂₅(SCH₂CH₂Ph)₁₈^-], where TOA⁺ = N(C₈H₁₇)₄⁺. The crystal structure reveals three types of gold atoms: (a) one central gold atom whose coordination number is 12 (12 bonds to gold atoms); (b) 12 gold atoms that form the vertices of an icosahedron around the central atom, whose coordination number is 6 (five bonds to gold atoms and one to a sulfur atom), and (c) 12 gold atoms that are stellated on 12 of the 20 faces of the Au₁₃ icosahedron. The arrangement of the latter gold atoms may be influenced by aurophilic bonding. Together they form six orthogonal semirings, or staples, of −Au₂(SCH₂CH₂Ph)₃− in an octahedral arrangement around the Au₁₃ core.