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Ag+-mediated base pairing is valuable for synthesising DNA-based silver nanoparticles (AgNPs) and nanoclusters (AgNCs). Recently, we reported the formation of a [Ag(cytidine)2]+ complex in dimethyl sulfoxide (DMSO), which facilitated the evaluation of the effect of cytosine–Ag+–cytosine (C–Ag+–C) base pairing on the degree of AgNP aggregation in solution. As an aprotic solvent, DMSO was expected to dissolve the [Ag(cytidine)2]+ complex, and powerful reducing agents, such as organic electron donors. In this study, the chemical reduction of a cytidine/Ag+ system using a powerful reducing agent tetrakis(dimethylamino)ethylene (TDAE) was investigated. 1H/13C/15N NMR spectroscopic evidence was obtained to identify the iminium dication (TDAE2+), which is an oxidised form of TDAE. The results were compared with those obtained using another organic electron donor, tetrathiafulvalene (TTF), which exhibits a relatively lower reduction activity than TDAE. AgNPs prepared via redox reaction between [Ag(cytidine)2]+ and organic electron donors (TDAE and TTF) were characterised using UV–Vis spectroscopy and nanoparticle tracking analysis. It was found that the formation of C–Ag+–C base pairing inhibited the aggregation of AgNPs in solution. In addition, in the presence of cytidine, the total concentration of the AgNP solution was affected by the reduction activity of the reducing agent. [ABSTRACT FROM AUTHOR]

The redox properties of metallo-base pairs remain to be elucidated. Herein, we report the detailed 1H/13C/109Ag NMR spectroscopic and cyclic voltammetric characterisation of the [Ag(cytidine)2]+ complex as isolated cytosine–Ag+–cytosine (C–Ag+–C) base pairs. We also performed comparative studies between cytidine/Ag+ and other nucleoside/Ag+ systems by using cyclic voltammetry measurements. In addition, to evaluate the effect of [Ag(cytidine)2]+ formation on the chemical reduction of Ag+ to Ag, we utilised the redox reaction between Ag+ and tetrathiafulvalene (TTF). We found that Ag+-mediated base pairing lowers the redox potential of the Ag+/Ag couple. In addition, C–Ag+–C base pairing makes it more difficult to reduce captured Ag+ ions than in other nucleoside/Ag+ systems. Remarkably, the cytidine/Ag+ system can be utilised to control the redox potential of the Ag+/Ag couple in DMSO. This feature of the cytidine/Ag+ system may be exploited for Ag nanoparticle synthesis by using the redox reaction between Ag+ and TTF. [ABSTRACT FROM AUTHOR]

Ag + -mediated base pairing is valuable for synthesising DNA-based silver nanoparticles (AgNPs) and nanoclusters (AgNCs). Recently, we reported the formation of a [Ag(cytidine) 2 ] + complex in dimethyl sulfoxide (DMSO), which facilitated the evaluation of the effect of cytosine-Ag + -cytosine (C-Ag + -C) base pairing on the degree of AgNP aggregation in solution. As an aprotic solvent, DMSO was expected to dissolve the [Ag(cytidine) 2 ] + complex, and powerful reducing agents, such as organic electron donors. In this study, the chemical reduction of a cytidine/Ag + system using a powerful reducing agent tetrakis(dimethylamino)ethylene (TDAE) was investigated. 1 H/ 13 C/ 15 N NMR spectroscopic evidence was obtained to identify the iminium dication (TDAE 2+ ), which is an oxidised form of TDAE. The results were compared with those obtained using another organic electron donor, tetrathiafulvalene (TTF), which exhibits a relatively lower reduction activity than TDAE. AgNPs prepared via redox reaction between [Ag(cytidine) 2 ] + and organic electron donors (TDAE and TTF) were characterised using UV-Vis spectroscopy and nanoparticle tracking analysis. It was found that the formation of C-Ag + -C base pairing inhibited the aggregation of AgNPs in solution. In addition, in the presence of cytidine, the total concentration of the AgNP solution was affected by the reduction activity of the reducing agent.

The redox properties of metallo-base pairs remain to be elucidated. Herein, we report the detailed 1H/13C/109Ag NMR spectroscopic and cyclic voltammetric characterisation of the [Ag(cytidine)2]+ complex as isolated cytosine-Ag+-cytosine (C-Ag+-C) base pairs. We also performed comparative studies between cytidine/Ag+ and other nucleoside/Ag+ systems by using cyclic voltammetry measurements. In addition, to evaluate the effect of [Ag(cytidine)2]+ formation on the chemical reduction of Ag+ to Ag, we utilised the redox reaction between Ag+ and tetrathiafulvalene (TTF). We found that Ag+-mediated base pairing lowers the redox potential of the Ag+/Ag couple. In addition, C-Ag+-C base pairing makes it more difficult to reduce captured Ag+ ions than in other nucleoside/Ag+ systems. Remarkably, the cytidine/Ag+ system can be utilised to control the redox potential of the Ag+/Ag couple in DMSO. This feature of the cytidine/Ag+ system may be exploited for Ag nanoparticle synthesis by using the redox reaction between Ag+ and TTF.