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Lookup NU author(s): Liam Mcgarry, Dr Osama El-ZubirORCiD, Dr Paul Waddell, Dr Fabio Cucinotta, Professor Andrew HoultonORCiD, Dr Ben Horrocks
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2023 The Royal Society of Chemistry.We describe a simple coordination compound of Au(i) and 6-thioguanosine, [Au(6-tGH)2]Cl, that has a rich self-assembly chemistry. In aqueous solution, the discrete complex assembles into a supramolecular fibre and forms a luminescent hydrogel at concentrations above about 1 mM. Below this concentration, the macromolecular structure is a vesicle. Through appropriate control of the solvent polarity, the gel can be turned into a lamellar film or crystallised. The molecular structure of [Au(6-tGH)2]Cl was determined using single crystal X-ray diffraction, which showed bis-6-thioguanosine linearly coordinated through the thione moiety to a central Au(i) ion. In the vesicles, the photoluminescence spectrum shows a broad, weak band at 550 nm owing to aurophilic interactions. Co-operative self-assembly from vesicle to fibre is made possible through halogen hydrogen bonding interactions and the aurophilic interactions are lost, resulting in a strong photoluminescence band at 490 nm with vibronic structure typical of an intraligand transition. The vesicle-fibre transition is also revealed by a large increase of ellipticity in the circular dichroism spectrum with a prominent peak near 390 nm owing to the helical structure of the fibres. Atomic force microscopy shows that at the same time as fibres form, the sample gels. Imaging near the vesicle-fibre transition shows that the fibres form between vesicles and a mechanism for the transition based on vesicle collisions is proposed.
Author(s): McGarry LF, El-Zubir O, Waddell PG, Cucinotta F, Houlton A, Horrocks BR
Publication type: Article
Publication status: Published
Journal: Soft Matter
Year: 2023
Volume: 19
Pages: 8386-8402
Online publication date: 19/10/2023
Acceptance date: 19/10/2023
Date deposited: 06/11/2023
ISSN (print): 1744-683X
ISSN (electronic): 1744-6848
Publisher: Royal Society of Chemistry
URL: https://doi.org/10.1039/D3SM01006F
DOI: 10.1039/d3sm01006f
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