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Atomically precise thiolate-protected gold nanomolecules have attracted interest due to their distinct electronic and chemical properties. The structure of these nanomolecules is important for understanding their peculiar properties. Here, we report the X-ray crystal structure of a 24-atom gold nanomolecule protected by 16 tert -butylthiolate ligands. The composition of Au 24 (S-C 4 H 9 ) 16 {poly[hexadecakis(μ- tert -butylthiolato)tetracosagold]} was confirmed by X-ray crystallography and electrospray ionization mass spectrometry (ESI–MS). The nanomolecule was synthesized in a one-phase synthesis and crystallized from a hexane–ethanol layered solution. The X-ray structure confirms the 16-atom core protected by two monomeric and two trimeric staples with four bridging ligands. The Au 24 (S-C 4 H 9 ) 16 cluster follows the shell-closing magic number of 8.
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Ion mobility–tandem mass spectrometry of bulky tert ‐butyl thiol ligated gold nanoparticles
Abstract Gold nanoparticles (AuNPs) synthesized in the 1–3 nm range have a specific number of gold core atoms and outer protecting ligands. They have become one of the “hot topics” in recent decades because of their interesting physical and chemical properties. The characterization of their structures is usually achieved by crystal X‐ray diffraction although the structures of some AuNPs remain unknown because they have not been successfully crystallized. An alternative method for studying the structure of AuNPs is electrospray ionization–ion mobility–tandem mass spectrometry (ESI‐IM‐MSMS). This research evaluated how effectively ESI‐IM‐MSMS using the commercially available Waters Synapt XS instrument yielded useful structural information from two AuNPs; Au23(S‐tBu)16and Au30(S‐tBu)18. The study used the maximum range of available collision energies along with ion mobility separation to measure the energy‐dependence of the product ions and their drift times which is a measure of their spatial size. For Au23(S‐tBu)16, the dissociation gave the masses of the outer protecting monomeric [RS–Au–SR] and trimeric [SR–Au–SR–Au–SR–Au–SR] staples where R = tBu, and complete dissociation of the outer layer Au andtBu groups to reveal the Au15S8core. For Au30(S‐tBu)18, the dissociation products was primarily through the loss of the partial ligands S‐tBu andtBu from the outer protecting layer and the loss of single Au4(S‐tBu)4unit. These results showed the that ESI‐IM‐MSMS analysis of the smaller Au23(S‐tBu)16gave information on all it major structural components whereas for Au30(S‐tBu)18, the overall structural information was limited to the ligands of the outer layer.
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- Award ID(s):
- 1808138
- PAR ID:
- 10643154
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Mass Spectrometry
- Volume:
- 59
- Issue:
- 2
- ISSN:
- 1076-5174
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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