On the interaction of magnetic iron clusters with hydrocarbons: Fe4–propane

The interaction of propane with Fe4 was studied by means of the BPW91/6-311+G(d,p) method. The two modes Fe4–CmH2– (CtH3)2 (I) and Fe4–CtH3–CmH2-CtH3 (II) were found. Their spin state is high (2S = 14), and propane interacts with Fe4 (t and m are for the terminal and middle C atoms) throughout the formation of two weak CxH–Fe bonds in I (x = m) and II (x = t), which bear some resemblance with classical agostic bonds. The vibrational pattern of propane is perturbed significantly, and its dipole moment shows a big increase. Thus, Fe4 is able to activate the propane molecule.