Three-Dimensional Porous Architectures Based on MnII/III Three-Blade Paddle Wheel Metallacryptates

Three metallacryptate supramolecular assemblies have been obtained using salicylhydroxamic acid derivatives (H3L). The three ligands differ in the residue at the para position with respect to the hydroxamic function (-H, -NH2, and -(4-pyridyl)). The core of these supramolecules correspond to the formula [(Mn-II)(2)(Mn-III)(9)(mu(3)-O)(4)(OAc)(3)(Shi)(6)](2+) (abbreviated as Mn11L6) in all three compounds. Additional acetate or hydroxide ions and DMF molecules are coordinated to the Mn-III ions. With L3- = Shi(3-) the Mn11L6 units assemble into a nonporous structure, where the metallacryptates are linked together through Na-I ions bridging between the units. Conversely, with L3- = p-aShi(3-) (NH2 group) and p-pyShi(3-) (4-pyridyl group) the units assemble in parallel chains and into a MOF-like structure, respectively. In both solids, a honeycomb porous architecture was obtained, where infinite channels run along the crystal structure. With p-aShi(3-), Na-I bridging ions and hydrogen bonds, provided by the presence of the amino group, characterize the interactions between the parallel chains of supramolecules. On the other hand, with p-pyShi(3-), the peripheral pyridyl groups point away from the metallacryptate units and are coordinated to available positions on Mn-III ions of neighboring molecules, with formation of a peculiar porous-coordination polymeric architecture.