Quantum Monte Carlo Simulations and High‐Field Magnetization Studies of Antiferromagnetic Interactions in a Giant Hetero‐Spin Ring

Chromium lanthanide heterometallic wheel complexes {Cr₈Ln₈} (Ln=Gd, Dy and Y) with alternating metal centres are presented. Quantum Monte Carlo simulations reveal antiferromagnetic exchange‐coupling constants with an average of 2.1 K within the {Cr₈Gd₈} wheel, which leads to a large ground spin state (S _T=16) that is confirmed by magnetization studies up to 20 Tesla. The {Cr₈Dy₈} wheel is a single‐molecule magnet.