Co(II) chemistry of 2,6-bis(2-pyridylcarbonyl)pyridine: an icosanuclear Co cluster exhibiting superparamagnetic relaxation.

High-nuclearity transition-metal complexes (clusters) are of special interest in chemistry and physics because, both in terms of size and physical properties, they bridge the gap between the microscopic and macroscopic world, and between quantum and classical systems. In terms of size, the smallest classical nanoparticles fabricated today are the same size as the largest metal clusters that are synthesized by bottom-up methods. In terms of physical properties, certain transition-metal clusters exhibit single-molecule magnetism at low temperatures, that is, they retain their magnetization in zero field in a manner analogous to that of classical macroscopic magnets, but at the same time they …

Hexanuclear Manganese(III) Single-Molecule Magnets