Fig. 5. Tracking the transformation process from Ag₂₄ to Ag₇₀ by ESI-MS and UV-vis spectroscopy. (a) Negative-ion mode ESI-MS spectra of Ag₂₄ in different solutions. (b) Top: UV-vis absorption spectra of Ag₂₄ (dissolved in CH₂Cl₂) and Ag₇₀ (dissolved in DMF); Bottom: time-dependent UV-vis absorption spectra of Ag₂₄ dissolved in DMF for tracking the transformation process from Ag₂₄ (yellow solution) to Ag₇₀ (red solution).