1.Department of Chemistry and Biochemistry, Shippensburg University, Shippensburg, PA, 17257, USA ;2.Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA ;
Abstract:
A series of heterotrimetallic manganese-lanthanide-sodium dimer metallacrowns has been synthesized and characterized by single-crystal X-ray analysis: {LnNa12-MCMn(III)N(shi)-4]}2(iph)4, where LnIII?=?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; shi3? is salicylhydroximate; and iph2? is isophthalate. The manganese(III) ions and shi3? ligands generate the 12-MC-4 framework with one LnIII 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 LnIII ion and each ring MnIII ion, and the meta-arrangement of the carboxylate groups joins two LnNa12-MCMn(III)N(shi)-4] units together to form the dimer through the LnIII ions, which reside on the interior of the molecule. The identity of the central LnIII ion slightly impacts the size the 12-MCMn(III)N(shi)-4] framework. As the crystal radius of the LnIII ion increases from LuIII (1.02 Å) to LaIII (1.19 Å), the 12-MC-4 framework expands to accommodate the larger LnIII ion as the MC cavity increases in size (0.53 Å for LuIII to 0.58 Å for LaIII) and the average cross cavity MnIII-MnIII and oxime oxygen-oxime oxygen distances also increase (MnIII-MnIII distances: 6.48 Å for LuIII to 6.52 Å for LaIII; Ooxime-Ooxime distances: 3.66 Å for LuIII to 3.75 Å for LaIII). In addition, the larger LnIII ions reside further from the MC cavity as indicated by the LnIII-oxime oxygen mean plane (OoxMP) distance. The LnIII-OoxMP distance steadily decreases from LaIII (1.7527(12) Å) to LuIII (1.5575(15) Å).
Graphic Abstract
The complex {LaNa12-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