Green Gold: Au₃₀(S-t-C₄H₉)₁₈ Molecules

Abstract

Here, we report the synthesis and separation of Au 30 (tert-thiol) 18 (tert-thiol = tert-butanethiol and 1-adamantanethiol) from a mixture of sizes of bulky-ligated nanoparticles. With precisely 30 gold metal atoms and 18 tertiary butyl ligands, this new 30 Au atom molecule is assigned a formula based on results obtained in high-resolution electrospray ionization (ESI) mass spectrometry. UV-vis-NIR spectroscopy shows a distinct electronic transition featured at 620 nm, with a valley in the green wavelength 520−570 nm region, explaining the green appearance. This lack of absorbance in the green region is uncommon, and therefore, metal nanoparticles of green color are extremely rare. Its optical band gap, 1.76 eV is much different than the 1.3 eV reported for Au 25 (SR) 18 . We report its reproducible direct synthesis (∼10 mg) in a one-pot reaction, with two different ligands. Because of the unique optical properties and altered-discrete sizes, there is a fundamental need for structural analysis of this nanoparticle.

Atomically Precise Bimetallic Nanoclusters as Photosensitizers in Photoelectrochemical Cells

“…As shown in Figure S1 (Supporting Information), the excited‐state lifetime of 1 is estimated to be about 50 ns. All of these observations suggest that 1 could be a promising candidate for applications in light‐harvesting systems …”

“…All of these observations suggest that 1 could be ap romising candidate for applicationsi nl ight-harvesting systems. [52] TNA were prepared by the anode oxidation method (see Experimental Section in the Supporting Information). As shown in Figures 2a and S2 (Supporting Information), compact and verticallya ligned nanotube arrays wereg rown on the substrate, with an average length of 5 mma nd an average diameter of 100 nm.…”

Time‐dependent density‐functional study of the photoabsorption spectrum of Au25(SC2H4C6H5)18 anion: Validation of the computational protocol

“…Of course this is a difficult task since many systems should be considered with well‐characterized structures and optical properties to assess the general validity. As a first step in this direction we considered the cluster Au 30 (S‐ t But) 18 , also known as “green gold.” We report in Figure the simulated optical spectra for the Au 30 (S‐ t But) 18 cluster calculated with SAOP, LB94, and PBE xc‐potentials, with TZP basis set and experimental geometry, with only H atoms positions optimized. For this system the choice of the xc‐functional is not so crucial: SAOP and LB94 give almost identical profiles, while PBE is being slightly shifted to lower energy.…”

Gas Phase Formation, Structure and Reactivity of Gold Cluster Ions

“…The role of the ligand (1,3-bis(dicyclohexylphosphino)propane versus 1,3-bis(diphenylphosphino)propane) in the growth of AuNCs and their fragmentation reactions have been examined via ESI-MS and CID [363]. ESI-MS was used to assign the novel AuNCs Au 10 (HSPh-pNH 2 ) 10 (where HSPh-pNH 2 =4-aminothiophenol) by the formation of charged adducts such as [Au 10 (HSPh-pNH 2 ) 10 +H + ] + [364] and Au 30 (tert-thiol) 18 (tert-thiol=tert-butanethiol and 1-adamantanethiol) [365] which also used MALDI-MS. Laser ablation has been used to synthesize gold carbides [366] and gold arsenides [367]. MALDI of lysozyme-Au adducts produces the following bare gas phase AuNC cations: Au 18 + , Au 25 + , Au 38 + , and Au 102 + .…”