Inorganic Approach to Stabilizing Nanoscale Toroidicity in a Tetraicosanuclear Fe<sub>18</sub>Dy<sub>6</sub> Single Molecule Magnet
Hagen Kaemmerer, Amer Baniodeh, Yan Peng, Eufemio Moreno Pineda, Michael Schulze, Christopher E. Anson, Wolfgang Wernsdorfer, Jürgen Schnack, Annie K. Powell
Abstract
Cyclic coordination clusters (CCCs) are proving to provide an extra dimension in terms of exotic magnetic behavior as a result of their finite but cyclized chain structures. The Fe18Dy6 CCC is a Single Molecule Magnet with the highest nuclearity among Ln containing clusters. The three isostructural compounds [Fe18Ln6(μ-OH)6(ampd)12(Hampd)12(PhCO2)24](NO3)6·38MeCN for Ln = DyIII (1), LuIII (2), or YIII (3), where H2ampd = 2-amino-2-methyl-1,3-propanediol, are reported. These can be described in terms of the cyclization of six {Fe3Ln(μOH)(ampd)2(Hampd)2(PhCO2)4}+ units with six nitrate counterions to give the neutral cluster. The overall structure consists of two giant Dy3 triangles sandwiching a strongly antiferromagnetically coupled Fe18 ring, leading to a toroidal arrangement of the anisotropy axis of the Dy ions, making this the biggest toroidal arrangement on a molecular level known so far.