Syntheses and Crystal Structures of a Series of Dysprosium-Manganese-Sodium 12-Metallacrown-4 Compounds with Halogenated Benzoate Bridging Anions

A series of heterotrimetallic dysprosium-manganese-sodium 12-metallacrown-4 compounds has been synthesized and characterized by single-crystal X-ray analysis: DyNaX4[12-MCMn(III)N(shi)-4], where X- = 2-fluorobenzoate (1), 3-fluorobenzoate (2), 4-fluorobenzoate (3), 2-chlorobenzoate (4), 4-chlorobenzoate (5), 3-bromobenzoate (6), and 2-iodobenzoate (7); MC is metallacrown; and shi(3-) is salicylhydroximate. Each 12-MC-4 framework is comprised of four ring Mn-III ions and four shi(3-) ligands. The oxime oxygen atoms of the shi(3-) ligands produce a central cavity which then binds one Dy-III ion and one Na+ ion on opposite sides. In each molecule four halogenated benzoate anions bridge between the central Dy-III ion and the ring Mn-III ions via the carboxylate groups. The identity of the halogenated benzoate anion has little effect on the structure of the [12-MCMn(III)N(shi)-4] framework as determined by several metrical parameters: the MC cavity radius, the average cross cavity Mn-III-Mn-III distance, the average cross cavity oxime oxygen-oxime oxygen distance, and the distance of the Dy-III from the oxime oxygen mean plane. For 1-7 these metrical parameters are strikingly similar; thus, providing further reinforcement of one hallmark of metallacrown chemistry-the ability to substitute various components of the molecule without affecting the overall structure which can be used for the fine-tuning of molecular properties. [GRAPHICS] .