Spectroscopic studies on organometallic compounds. Part XVII. Infrared spectra of dicarbonyl-(π-cyclopentadienyl)iron complexes in the carbonyl stretching regions

Abstract

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.