Spectroscopic studies on organometallic compounds. Part XVII. Infrared spectra of dicarbonyl-(π-cyclopentadienyl)iron complexes in the carbonyl stretching regions
The i.r. spectra of a series of complexes (π-C5H5)Fe(CO)2X (X = halogen, SiCl3, GeCl3, SnCl3, SnPh3, and SnMe3) and that of the related complex (π-C5H5)Co(CO)2 have been examined in the fundamental and binary carbonyl stretching regions. The results for the tin–iron complexes are interpreted in terms of an increase in the importance of π-bonding along the ligand series SnMe3, SnPh3, and SnCl3. For the halogen complexes σ-bonding between iron and the halides is considered to be the dominant factor. A tentative interpretation of the relative intensities of the binary combination bands is presented.