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Metal-ion-containing soft materials include metallogels, metal-organic frameworks, and coordination polymers. These materials show commercial value in catalysis, hydrogen storage, and electronics. Metal-containing soft materials reported to date are structurally weak, falling short of a Young’s modulus typical of engineering-grade materials. We report herein that inclusion of an antisolvent in metal-thiolate metallogel synthesis results in a colloidal sol, where the colloids comprise amorphous metal-organic complexes. Upon desolvation, the colloids coalesce to form a solid phase that is both gel like and glass like. This solid phase is structurally amorphous, comprises continuous networks similar to organic polymers, and has stiffness observed in polymeric materials with extended structure, yet contains a superstoichiometric amount of metal relative to organic ligand. The solid phase is therefore a rigid, amorphous metal-rich (RAMETRIC) material. Highlighting the rigidity, the Young’s modulus of the gel-phase material is 1,000× greater than metallogels comprised of the same constituent building blocks. 

A modification of Au25(pMBA)18 that incorporates one diglyme ligand as a direct synthetic product is reported. Notably the expected statistical production of clusters containing other ligand stoichiometries is not observed. This Au25(pMBA)17diglyme product is characterized by electrospray ionization mass spectrometry (ESI-MS) and optical spectroscopy. Thiolate for thiolate ligand exchange proceeds on this cluster, whereas thiolate for diglyme ligand exchange does not. 

Abstract ASASSN-14ko is a recently discovered periodically flaring transient at the center of the active galactic nucleus (AGN) ESO 253−G003 with a slowly decreasing period. Here, we show that the flares originate from the northern, brighter nucleus in this dual-AGN, post-merger system. The light curves for the two flares that occurred in 2020 May and September are nearly identical over all wavelengths. For both events, Swift observations showed that the UV and optical wavelengths brightened in unison. The effective temperature of the UV/optical emission rises and falls with the increase and subsequent decline in the luminosity. The X-ray flux, by contrast, first rapidly drops over ∼2.6 days, rises for ∼5.8 days, drops again over ∼4.3 days, and then recovers. The X-ray spectral evolution of the two flares differ, however. During the 2020 May peak the spectrum softened with increases in the X-ray luminosity, while we observed the reverse for the 2020 September peak. We found a small change in the period derivative, which seems to indicate that the system does not have a static period derivative and there is some stochasticity in its evolution.