Biochemistry & Pharmacology: Open Access
Open Access
ISSN: 2167-0501
+44-77-2385-9429
ISSN: 2167-0501
+44-77-2385-9429
Kana Yoshida and Yuichi Negishi
Tokyo University of Science, Japan
Posters & Accepted Abstracts: Biochem Pharmacol (Los Angel)
Small thiolate-protected gold clusters show size-specific physical and chemical properties, which are not observed in bulk
gold. Especially, hydrophilic thiolate-protected gold clusters exhibit a good affinity for biomaterials. Therefore, much
research has been conducted in this field. However, it is difficult to selectively synthesize the clusters with specific chemical
composition. Therefore, to evaluate properties of hydrophilic thiolate-protected gold clusters accurately, we need to separate
single cluster from the mixture of these clusters with high resolution. In this work, we report on precise separation of various
hydrophilic thiolate-protected gold clusters (Aun(SR)m, SR=SG (glutathionate), NALC (N-acetyl-L-cysteine), p-MBA
(p-mercaptobenzoic acid)) by hydrophilic interaction liquid chromatography (HILIC). Furthermore, we attempted to evaluate
the chemical composition of each cluster by introducing LC/MS which was directly connected the chromatograph with the
mass spectrometer. The mixture of clusters used in this work was synthesized by reducing gold ions in the presence of thiols.
Figure 1(a) shows the UV chromatogram of Aun(SG)m. Multiple peaks were observed in the chromatogram. Figure 1(b) shows
the ESI-mass spectrum of each peak observed in the chromatogram. It was found that almost only one cluster was contained
in each peak. These results indicate that mixture was separated with high resolution according to the chemical composition
of clusters. Similar separation has also been achieved for Aun(NALC)m and Aun(p-MBA)m. Therefore, it was revealed that
the use of HILIC columns is powerful tool for separating of gold clusters protected by many kinds of hydrophilic thiolates.
Furthermore, Although chemical compositions observed for Aun(SG)m and Aun(NALC)m were similar each other, that for
Aun(p-MBA)m was less compared with these clusters. These results indicate that chemical compositions of the Aun(SR)m vary
depending on the ligand structure. In this manner, we have succeeded in revealing how difference of ligand affects synthesis of
gold clusters protected by hydrophilic thiolate ligands.
Recent Publications
1. K Yoshida, Y Negishi, et al. (2018) High-performance liquid chromatography mass spectrometry of gold and alloy
clusters protected by hydrophilic thiolates. Nanoscale, 10:1641-1649.
2. Y Negishi, et al. (2017) Separation of glutathionate-protected gold clusters by reversed-phase ion pair high-performance
liquid chromatography. Ind. Eng. Chem. Res. 56:1029-1035.
3. Y Negishi, et al. (2016) Precise synthesis, functionalization and application of thiolate-protected gold clusters. Coord.
Chem. Rev. 320-32:238-250.
4. Y Negishi, et al. (2015) A critical size for emergence of nonbulk electronic and geometric structures in dodecanethiolateprotected
au clusters. J. Am. Chem. Soc. 137:1206-1212.
5. Y Negishi, et al. (2014) Advanced use of high-performance liquid chromatography for synthesis of controlled metal
clusters. Nanoscale 6:7889-7896.
Kana Yoshida has completed her BSc in 2017 in Applied Chemistry at Tokyo University of Science, Japan. Her main research interests are high resolution separation of noble metal clusters protected by hydrophilic thiolate ligands. She has presented her work many times at conferences. Furthermore, her research was published to Nanoscale (IF=7.367) which is one of the high impact factor journal in nanoscience field.
E-mail: kn.cwxjig717@gmail.com