G4-quartet hydrogels from 5′-hydrazino-guanosine for the non-covalent and covalent remediation of contaminants from water. (4th July 2018)

• Record Type: Journal Article
• Authors: Xiao, Songjun; Davis, Jeffery T.
• Is Part Of: Faraday discussions. Volume 209(2018)
• Page Start: 97
• Page End: 112
• Publication Date: 2018-07-04
• Subjects: Chemistry -- Periodicals; Metallurgy -- Periodicals; Electrochemistry -- Periodicals; 540
• DOI: 10.1039/c8fd00038g
• Languages: English
• ISSNs: 1359-6640

Abstract

Abstract : HG2 ·KCl hydrogel assemblies non-covalently bind anionic dyes and covalently bind an aldehyde in water. Abstract : The creation of supramolecular hydrogels from relatively simple building blocks demonstrates the power of molecular self-assembly to make functional materials. G4 -quartet hydrogels are appealing for a number of applications, including the environmental remediation of pollutants in water. We find that the guanosine analog, 5′-deoxy-5′-hydrazinoguanosine (HG2 ) self-assembles into a self-standing hydrogel in the presence of stoichiometric amounts (0.25 equiv.) of KCl. The higher water solubility of HG2 (14.5 mM), compared to that of the parent compound G1 (2.1 mM), likely contributes to its enhanced gelation. The structural basis for this HG2 ·KCl hydrogel, confirmed by PXRD, IR and CD, is the G4 ·K + quartet, which forms extended 1D ion-channel assemblies that entangle to give a stable and long-lived hydrogel. We also find that adding KCl to a saturated solution of HG2 triggers the generation of colloidal G4 ·K + assemblies in situ that selectively and efficiently binds the anionic dye naphthol blue black (NBB) over a cationic dye. In addition to this non-covalent electrostatic binding of anions, the nucleophilic 5′-hydrazino group in the HG2 ·KCl hydrogel HG2 enables the efficient absorption of propionaldehyde from both the gas phase and from water solution via the formation of covalent hydrazone linkages with the gel matrix.