| Abstract
| - Reactions of laser-ablated Fe atoms with halomethanes and ethane have been investigated through matrix infrared spectra and density functional calculations. Only insertion complexes are identified from reactions of Fe with methyl fluoride and ethane, parallel to the previously observed insertion complex CH3−FeH from the photochemical reaction with methane. However, Fe also forms methylidene complexes through α-X migration in the insertion products from Fe reactions with di-, tri-, and tetrahalomethanes. Calculated structures show no agostic distortion in these methylidene complexes. However, an interesting distortion and elongation of the C−Cl bond is observed in the Fe insertion products, such as H2ClC−FeCl, while no such distortion of the C−H or C−F bond is found in analogous calculated structures for H2FC−FeCl. This distortion is likely due to a Cl lone pair to Fe bonding interaction that ultimately leads to formation of the lower energy CH2FeCl2 methylidene complex. This Cl atom transfer is reversible on visible−ultraviolet irradiation. There is no evidence for methylidyne complexes of the type recently observed for Ru, as such higher oxidation state structures become more stable on going down the family group.
- The H2ClC−FeCl insertion complex is distorted by the chlorine lone pair to iron 3d orbital interaction, whereas the H3C−FeF complex is trigonal.
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