Molecule-based magnets with diruthenium building blocks in two and three dimensions

Several molecule-based magnets can be constructed from diruthenium tetracarboxylate building blocks. We study two such materials with antiferromagnetic interactions between Cr(III) ions and diruthenium paddle-wheel complexes. While collinear magnetic ordering in the three-dimensional compound is frustrated by the easy-plane anisotropy on the diruthenium paddle wheel, the two-dimensional compound has a collinear ferrimagnetic ground state because of the dominant coupling between the Cr ions and the in-plane diruthenium species.