One-pot synthesis of thiol-modified liquid crystals conjugated fluorescent gold nanoclusters

Po Hsuan Hsu, Sibidou Yougbaré, Jui Chi Kuo, Dyah Ika Krisnawati, Achmad Jazidie, Mohammad Nuh, Po Ting Chou, Yu Cheng Hsiao, Tsung Rong Kuo

Research output: Contribution to journalArticle

Abstract

Gold nanoclusters (AuNCs) and liquid crystals (LCs) have shown great potential in nanobiotechnology applications due to their unique optical and structural properties. Herein, the hardcore of the 4-cyano biphenyl group for commonly used LCs of 4-cyano-4′-pentylbiphenyl (5CB) was utilized to synthesize 4′-(2-mercaptoethyl)-(1,1′-biphenyl)-4-carbonitrile (TAT-12) based on Suzuki coupling and Appel reaction. The structural and optical properties of thiol-modified TAT-12 LCs were demonstrated by nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and differential scanning calorimetry (DSC). By one-pot synthesis, thiol-modified TAT-12 LCs were used as the ligands to prepare fluorescent gold nanoclusters (AuNCs@TAT-12) according to the Au-S bond between AuNCs and TAT-12. The spectra of UV-vis absorption and X-ray photoelectron spectroscopy (XPS) of AuNCs@TAT-12 indicated that the core of gold of AuNCs@TAT-12 exhibited high gold oxidation states. The fluorescence of AuNCs@TAT-12 was observed with a maximum intensity at ~352 nm coming from TAT-12 on AuNCs@TAT-12 and the fluorescence quantum yield of AuNCs@TAT-12 was calculated to be 10.1%. Furthermore, the fluorescence with a maximum intensity at ~448 nm was attributed to a ligand–metal charge transfer between the ligands of TAT-12 LCs and the core of AuNCs. The image of transmission electron microscopy (TEM) further demonstrated an approximately spherical shape of AuNCs@TAT-12 with an average size of 2.3 nm. A combination of UV-vis absorption spectra, XPS spectra, fluorescence spectra and TEM image, fluorescent AuNCs@TAT-12 were successfully synthesized via one-pot synthesis. Our work provides a practical approach to the synthesis of LCs conjugated AuNCs for future applications in nanobiotechnology.
Original languageEnglish
Article number1755
Pages (from-to)1-9
Number of pages9
JournalNanomaterials
Volume10
Issue number9
DOIs
Publication statusPublished - Sep 1 2020

Keywords

  • Fluorescence
  • Gold nanoclusters
  • Ligand–metal charge transfer
  • Liquid crystals
  • Nanobiotechnology
  • Thiolate ligand

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)

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    Hsu, P. H., Yougbaré, S., Kuo, J. C., Krisnawati, D. I., Jazidie, A., Nuh, M., Chou, P. T., Hsiao, Y. C., & Kuo, T. R. (2020). One-pot synthesis of thiol-modified liquid crystals conjugated fluorescent gold nanoclusters. Nanomaterials, 10(9), 1-9. [1755]. https://doi.org/10.3390/nano10091755