The interaction of propane with Fe-4 was studied by means of the BPW91/6-311+G(d,p) method. The two modes Fe-4-CmH2-(CtH3)(2) (I) and Fe-4-CtH3-CmH2-CtH3 (II) were found. Their spin state is high (2S = 14), and propane interacts with Fe-4 (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, Fe-4 is able to activate the propane molecule. (c) 2007 Elsevier B.V. All rights reserved.