Hidden components in aqueous "Gold-144' fractionated by PAGE: high resolution orbitrap ESI-MS identifies the Gold-102 and higher all-aromatic Au-pMBA cluster compounds

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Date
2016
Authors
Alvarez, Marcos M.
Chen, Jenny
Plascencia-Villa, German
Black, David M.
Griffiths, Wendell P.
Garzon, Ignacio L.
Jose-Yacaman, Miguel
Demeler, Borries
Whetten, Robert L.
Journal Title
Journal ISSN
Volume Title
Publisher
American Chemical Society
Abstract
Experimental and theoretical evidence reveals the resilience and stability of the larger aqueous gold clusters protected with p-mercaptobenzoic acid ligands (pMBA) of composition Aun(pMBA)p or (n, p). The Au144(pMBA)60, (144, 60), or gold-144 aqueous gold cluster is considered special because of its high symmetry, abundance, and icosahedral structure as well as its many potential uses in material and biological sciences. Yet, to this date, direct confirmation of its precise composition and total structure remains elusive. Results presented here from characterization via high-resolution electrospray ionization mass spectrometry on an Orbitrap instrument confirm Au102(pMBA)44 at isotopic resolution. Further, what usually appears as a single band for (144, 60) in electrophoresis (PAGE) is shown to also contain the (130, 50), recently determined to have a truncated-decahedral structure, and a (137, 56) component in addition to the dominant (144, 60) compound of chiral-icosahedral structure. This finding is significant in that it reveals the existence of structures never before observed in all-aromatic water-soluble species while pointing out the path toward elucidation of the thermodynamic control of protected gold nanocrystal formation.
Description
Accepted author manuscript
Keywords
Cluster chemistry , Gold cluster , Cluster compounds
Citation
Alvarez, M. M., Chen, J., Plascencia-Villa, G., Black, D. M., Griffiths, W. P., Garzon, I. L., Jose-Yacaman, M., Demeler, B., & Whetten, R. L. (2016). Hidden components in aqueous "Gold-144" fractionated by PAGE: High resolution orbitrap ESI-MS identifies the Gold-102 and higher all-aromatic Au-pMBA cluster compounds. Journal of Physical Chemistry B, 120(26), 6430-6438. https://doi.org/10.1021/acs.jpcb.6b04525
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