Controlling the Atomic Structure of Au₃₀ Nanoclusters by a Ligand‐Based Strategy

Abstract

We report the X-ray structure of a gold nanocluster with 30 gold atoms protected by 18 1-adamantanethiolate ligands (formulated as Au30 (S-Adm)18 ). This nanocluster exhibits a threefold rotationally symmetrical, hexagonal-close-packed (HCP) Au18 kernel protected by six dimeric Au2 (SR)3 staple motifs. This new structure is distinctly different from the previously reported Au30 S(S-(t) Bu)18 nanocluster protected by 18 tert-butylthiolate ligands and one sulfido ligand with a face-centered cubic (FCC) Au22 kernel. The Au30 (S-Adm)18 nanocluster has an anomalous solubility (it is only soluble in benzene but not in other common solvents). This work demonstrates a ligand-based strategy for controlling nanocluster structure and also provides a method for the discovery of possibly overlooked clusters because of their anomalous solubility.

The fourth crystallographic closest packing unveiled in the gold nanocluster crystal

“…3l), indicating the uniqueness of Au–S bonding in the Au 60 S 6 (SCH 2 Ph) 36 nanocluster. Herein, the six surprising μ 4 -S atoms should come from the thiol, which may undergo S–C bond cleavage under heating conditions during the ligand-exchange-induced structure transformation process42. A single Au 20 S 3 (SR) 18 staple motif (branched at the site of the μ 4 -S atom) contains two -Au-SR-Au- and three -Au-SR-Au-SR-Au- units between the five terminal μ 2 -S atoms and three bridging μ 4 -S atoms, and one -Au-SR-Au-SR-Au- and one -Au-SR-Au-SR-Au-SR-Au- units among the three bridging μ 4 -S atoms (Fig.…”

“…reported the fcc crystallographic arrangement of Au 30 (SR) 18 nanoclusters in early 2016 (ref. 42), and very recently, Wu et al . reported the 4H crystallographic arrangement in Au 92 crystals43.…”

Observation of Non‐FCC Copper in Alkynyl‐Protected Cu53Nanoclusters

“…This can be one of the reasons for Cu being arranged in such ac losely packed structure.ESI-MS showed amain peak corresponding to dicationic [Cu 53 (CCPhPh) 9 (dppp) 6 Cl 2 (NO 3 ) 8 ] 2+ ,w hich indicated Cu 53 is electrically neutral and has 32 free electrons (Supporting Information, Figure S10, Figure S11;Z eta potential). Thirty-two does not seem to fit the electronic shell closing at the jellium electron counts of 2,8,18,20,34,40, and so on. Theelectron paramagnetic resonance (EPR;Supporting Information, Figure S12), however,d id not support the presence of unpaired electron.…”

“…[6] Forexample,athiolate stabilized Au 36 NC exhibits an ABC packing mode (FCC), while aA u 18 kernel was assembled into aABABpattern (HCP) in aAu 30 NC. [7,8] Even body-centered cubic (BCC) Au 38 NC was observed. [9] The decisive role of ligands on the kernel structure has also been exemplified by various Ag NCs.…”

“…The advances in crystallographic structure determination of Au and Ag NCs have explicitly revealed the two metals can be arranged in non‐FCC lattices when a dozen or more atoms are confined by appropriate ligands . For example, a thiolate stabilized Au 36 NC exhibits an ABC packing mode (FCC), while a Au 18 kernel was assembled into a ABAB pattern (HCP) in a Au 30 NC . Even body‐centered cubic (BCC) Au 38 NC was observed .…”