Structural Diversity of Compounds Based on Iron-Dithiolene with Sodium or Potassium Complexes

A series of iron dithiolene compounds with sodium or potassium complexes have been prepared by direct reactions. Their structures consist of coordination polymers of different dimensionalities or molecular compounds depending on the nature of the iron precursor, the presence or not of a donor substituent in the aromatic ring of the dithiolene ligand, and the amount of water molecules present during the crystallization. Since all these compounds are based on the combination of cationic alkaline and anionic iron-dithiolene entities that connect each other by coordination bonds, in order to favor local electroneutrality the structures obtained show that charged entities with a similar charge/size ratio pack more effectively. The flexibility of the potassium coordination environment seems to facilitate the structural diversity found for this family of compounds.