The fourth crystallographic closest packing unveiled in the gold nanocluster crystal

Metal nanoclusters have recently attracted extensive interest not only for fundamental scientific research, but also for practical applications. For fundamental scientific research, it is of major importance to explore the internal structure and crystallographic arrangement. Herein, we synthesize a gold nanocluster whose composition is determined to be Au 60 S 6 (SCH 2 Ph) 36 by using electrospray ionization mass spectrometry and single crystal X-ray crystallography (SCXC). SCXC also reveals that Au 60 S 6 (SCH 2 Ph) 36 consists of a fcc-like Au 20 kernel protected by a pair of giant Au 20 S 3 (SCH 2 Ph) 18 staple motifs, which contain 6 tetrahedral-coordinate μ 4 -S atoms not previously reported in the Au–S interface. Importantly, the fourth crystallographic closest-packed pattern, termed 6H left-handed helical (6HLH) arrangement, which results in the distinct loss of solid photoluminescence of amorphous Au 60 S 6 (SCH 2 Ph) 36 , is found in the crystals of Au 60 S 6 (SCH 2 Ph) 36 . The solvent-polarity-dependent solution photoluminescence is also demonstrated. Overall, this work provides important insights about the structure, Au–S bonding and solid photoluminescence of gold nanoclusters. Metal nanoclusters are explored for their precise structures and compelling properties. Here, the authors synthesize a gold cluster with unique structural features, including giant staple motifs, tetrahedral-coordinate μ 4 -S atoms, and a helical closest-packed crystallographic pattern that influences the cluster’s photoluminescence.