Does Symmetry Influence the Properties of [(Mn6CrIII)-Cr-III](3+) Single-Molecule Magnets?

Höke V, Stammler A, Bögge H, Glaser T. Does Symmetry Influence the Properties of [(Mn6CrIII)-Cr-III](3+) Single-Molecule Magnets? ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE. 2018;644(21):1354-1360.The triplesalen complex [(Mn6CrIII)-Cr-III](ClO4)(3) was synthesized and characterized by single-crystal X-ray diffraction, UV/Vis/NIR spectroscopy, and DC and AC magnetic susceptibilities. The molecular structure is D-3 symmetric, whereas all other salts and solvates of [(Mn6CrIII)-Cr-III](3+) are S-6 symmetric. The UV/Vis/NIR spectrum of D-3 symmetric [(Mn6CrIII)-Cr-III](3+) is almost identical to that of S-6 symmetric [(Mn6CrIII)-Cr-III](3+) demonstrating that the electronic structure is not significantly perturbed by the symmetry variation. The magnetic data of D-3 symmetric [(Mn6CrIII)-Cr-III](3+) is also similar to those of S-6 symmetric [(Mn6CrIII)-Cr-III](3+) with antiferromagnetic J(Mn-Mn) exchange coupling. This is in contrast to the ferromagnetic J(Mn-Mn) exchange coupling in the chiral (RR)[(Mn6CrIII)-Cr-III](3+) synthesized with a chiral triplesalen derivative. Due to the chirality, (RR)[(Mn6CrIII)-Cr-III](3+) is also of D-3 symmetry. However, its UV/Vis/NIR spectrum differs to those of D-3 and S-6 symmetric [(Mn6CrIII)-Cr-III](3+). This indicates that the electronic and magnetic properties of (RR)[(Mn6CrIII)-Cr-III](3+) are not different to those of [(Mn6CrIII)-Cr-III](3+) due to the symmetry variation but due to the specific properties of the two triplesalen ligands