Highly Porous Ionic Solids Consisting of AuI3CoIII2Complex Anions and Aqua Metal Cations

Treatment of Na₃[Au₃Co₂(D-pen)₆] (Na₃[1]; D-H₂pen = D-penicillamine) with M(OAc)₂ (M = NiII, MnII) in water gave ionic crystals of [M(H2O)6]3[1]2 (2M) in which [1]^3- anions are hydrogen-bonded with [M(H₂O)₆]²⁺ cations to form a 3D porous framework with a porosity of ca. 80%. Soaking crystals of 2Ni in its mother liquor afforded crystals of [Ni(H₂O)₆]₂[{Ni(H2O)4}(1)2] (3Ni) in which [1]^3- anions are connected to trans-[Ni(H₂O)₄]²⁺ and [Ni(H₂O)₆]²⁺ cations through coordination and hydrogen bonds, respectively, to form a 1D porous framework with a porosity ca. 60%. Further soaking crystals led to [{Ni(H2O)4}3(1)2] (4Ni), in which [1]^3- anions are connected to cis-[Ni(H₂O)₄]²⁺ and trans-[Ni(H2O)4]²⁺ cations through coordination bonds in a dense framework with a porosity of ca. 30%. A similar two-step crystal-to-crystal transformation mediated by solvent proceeded when crystals of 2Mn were soaked in a mother liquor. However, the transformation of 2Mn generated [{Mn(H₂O)₄}(H1)] (4′Mn) as the final product, in which [H1]^2- anions are connected to cis-[Mn(H₂O)₄]²⁺ cations through coordination bonds in a very dense framework with a porosity ca. 5% by way of [Mn(H2O)6]2[{Mn(H2O)4}(1)2] (3Mn), which is isostructural with 3Ni. While all the compounds adsorbed H₂O and CO₂ depending on the degree of their porosity, unusually large NH₃ adsorption capacities were observed for 4Ni and 4′Mn, which have dense frameworks. © 2021 American Chemical Society.