(163t) Metal-Ammonia Complexes: From Gas Phase Solvated Electron Precursors to Proposed Liquid-Metals and Metal-Amine Framework Materials

Solvated Electron Precursors (or SEPs) are metal-ammonia complexes M(NH₃)_x (x=4-6), which are present in metal-ammonia solutions of intermediate concentrations, and they are the building blocks for the so-called liquid or expanded metals. Despite their unique electronic and structural features, SEPs are poorly studied in the literature. We show that SEPs can accommodate one, two or three electrons that occupy diffuse hydrogenic-type orbitals distributed chiefly outside the M(NH₃)_x^q+ core. We further examined the biding of two such structures, and our findings suggest that the formation of new unexplored liquid metals is possible. Specifically, first-row transition metals form two independent electronic shells, one inner localized 3d-shell and one outer diffuse shell that contributes to the band structure of the liquid metal. Finally, we explored the possibility of connecting two metal ammonia complexes via hydrocarbon bridges using diamines. Our results propose a new type of porous materials resembling metal organic framework structures, but they are composed of metal centers with diffuse electrons in their periphery. Such systems can be used in redox catalytic systems.