Synthesis and Optical Properties of a Dithiolate/Phosphine-Protected Au28 Nanocluster

Abstract
While monothiols and simple phosphines are commonly exploited for size-controlled synthesis of atomically precise gold nanoclusters (NCs), dithiols or dithiol-phosphine combinations are seldom applied. Herein, we used a dithiol (benzene-1,3-dithiol, BDT) and a phosphine (triphenylphosphine, TPP) together as ligands and synthesized an atomically precise gold NC with the formula [Au28(BDT)4(TPP)9]2+. This NC exhibited multiple absorption features and a charge of +2, which are distinctly different from the reported all-thiolated [Au28(SR)20]0 NC (SR: monothiolate). The composition of [Au28(BDT)4(TPP)9]2+ NC was deduced from high-resolution electrospray ionization mass spectrometry (ESI MS) and it was further corroborated by thermogravimetric analysis (TGA). Differential pulse voltammetry (DPV) revealed a HOMO–LUMO gap of 1.27 eV, which is in good agreement with the energy gap of 1.3 eV obtained from its UV–vis spectrum. The successful synthesis of atomically precise, dithiol-protected Au28 NC would stimulate theoretical and experimental research into bidentate ligands as a new path for expanding the library of different metal NCs, which have so far been dominated by monodentate thiols.

Citation
Aljuhani MA, Bootharaju MS, Sinatra L, Basset J-M, Mohammed OF, et al. (2017) Synthesis and Optical Properties of a Dithiolate/Phosphine-Protected Au28 Nanocluster. The Journal of Physical Chemistry C. Available: http://dx.doi.org/10.1021/acs.jpcc.6b10205.

Acknowledgements
The work reported here was supported by KAUST.

Publisher
American Chemical Society (ACS)

Journal
The Journal of Physical Chemistry C

DOI
10.1021/acs.jpcc.6b10205

Additional Links
http://pubs.acs.org/doi/full/10.1021/acs.jpcc.6b10205

Permanent link to this record