Toroidal magnetic moments in Tb-4 squares

Terbium-based complexes are passable in the study of single molecule toroics (SMTs). Herein, the syntheses and characterizations of a series of Tb-4 SMTs isolated from reduced or dimerized Schiff base ligands are presented. These complexes share a similar mu(4)-O bridged Tb-4 square core and show diamagnetic ground states. Micro-SQUID technique was carried out on a single-crystal sample and the results suggest that there is a toroidal arrangement of the magnetic moments. Ab initio calculations are performed on these complexes and confirm the mixed-moment SMT properties. This allowed us to access a new strategy for generating single molecule toroics in terbium-based molecules.