Syntheses and Crystal Structures of a Series of Manganese-Lanthanide-Sodium 12-Metallacrown-4 Dimers

A series of heterotrimetallic manganese-lanthanide-sodium dimer metallacrowns has been synthesized and characterized by single-crystal X-ray analysis: {LnNa[12-MCMn(III)N(shi)-4]}(2)(iph)(4), where Ln(III) = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9), Ho (10), Er (11), Tm (12), Yb (13), Lu (14), and Y (15); MC is metallacrown; shi(3-) is salicylhydroximate; and iph(2-) is isophthalate. The manganese(III) ions and shi(3-) ligands generate the 12-MC-4 framework with one Ln(III) and Na+ ion bound to each [12-MCMn(III)N(shi)-4] on opposite sides of the central MC cavity. The carboxylate groups of the isophthalate ligands bridge between the central Ln(III) ion and each ring Mn-III ion, and the meta-arrangement of the carboxylate groups joins two LnNa[12-MCMn(III)N(shi)-4] units together to form the dimer through the Ln(III) ions, which reside on the interior of the molecule. The identity of the central Ln(III) ion slightly impacts the size the [12-MCMn(III)N(shi)-4] framework. As the crystal radius of the Ln(III) ion increases from Lu-III (1.02 angstrom) to La-III (1.19 angstrom), the 12-MC-4 framework expands to accommodate the larger Ln(III) ion as the MC cavity increases in size (0.53 angstrom for Lu-III to 0.58 angstrom for La-III) and the average cross cavity Mn-III-Mn-III and oxime oxygen-oxime oxygen distances also increase (Mn-III-Mn-III distances: 6.48 angstrom for Lu-III to 6.52 angstrom for La-III; O-oxime-O-oxime distances: 3.66 angstrom for Lu-III to 3.75 angstrom for La-III). In addition, the larger Ln(III) ions reside further from the MC cavity as indicated by the Ln(III)-oxime oxygen mean plane (OoxMP) distance. The Ln(III)-OoxMP distance steadily decreases from La-III (1.7527(12) angstrom) to Lu-III (1.5575(15) angstrom). Graphic The complex {LaNa[12-MCMn(III)N(shi)-4]}(2)(iph)(4)(DMF)(6)(H2O)(2) is a dimer of [12-MC-4] molecules linked by four isophthalate anions