Design and Synthesis of a Library of Molecule-Based Magnets: The Charge-Transfer Salt Approach

The rules governing magnetic coupling in molecule-based materials are still being defined. Until they are clear, synthetic efforts should ideally yield many new candidate magnets for a minimal investment of time and effort. One approach that satisfies this requirement is the synthesis of magnetic charge-transfer salts from metallocenes and easily identifiable organic acceptors. This strategy offers the possibility of synthesizing a library of structurally related compounds utilizing tunable building blocks and has yielded examples exhibiting interesting magnetic phenomena including ferromagnetism, metamagnetism, canted (weak) ferromagnetism, and spin glass behavior. In principle, this work should permit a systematic examination of structure–property relationships, leading to a better understanding of intermolecular magnetic coupling.