Iron–iron interaction through an ethanedithiolate ligand: a magnetic and theoretical study

The compound ([CpFe(dppe)]2[μ-SCH2CH2SS,S′])(PF6)2 ([1][PF6]2) has been synthesized and its magnetic properties have been investigated by susceptometer quantum interface device (SQUID) measurements in the temperature range 5–300 K. The d5–d512+ complex exhibits intramolecular antiferromagnetic behavior, with a magnetic coupling constant of −6.4 cm−1. Density functional theory (DFT) calculations on a model of 12+ (as well as on models of 1+ and 1) allow to determine its molecular structure and analyse its bonding and magnetic properties. The computed spin density exhibits significant localization on both the Fe and S centers. Replacing the heteroatoms of the bridging ligand by CH2 groups leads to a relocalization of the spin density on the metal atoms and favors ferromagnetic coupling.