Synthesis, structure, and magnetic properties of the charge-transfer salt ferromagnet decamethylchromocenium dimethyl dicyanofumarate, TCurie=5.7 K

Dimethyl dicyanofumarate, DMeDCF, has been used as an alternative to tetracyanoethylene for the construction of a new molecule-based ferromagnet. A crystal structure of the compound shows it to adopt essentially the same stacking motif as its TCNE analogue. Although DMeDCF is a weaker acceptor than TCNE and the Cr-Cr separations are generally greater than found for the TCNE analogue, the title compound has a higher T-Curie of 5.6 K. This result demonstrates the utility of DMeDCF while also showing that there are probably many structure-property relationships yet to be discovered in this class of compounds.