NMR study of some cyclopentadienyliron carbonyl derivatives

The PMR spectra of the compounds π-C 5 H 5 Fe(CO) 2 X (X = CH 3 , C 6 H 5 , COCH 3 , I, Br, Cl, CN) and π-C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ]C 6 H 4 R- p (R = OCH 3 , CH 3 , H, Cl, F, COOC 2 H 5 ) have been studied, and the effects of X and R substituents upon the cyclopentadienyl ring chemical shifts have been shown to be predominantly inductive. From the basis of 19 F spectra of the complexes π-C 5 H 5 Fe(CO)(L)C 6 H 4 F- m , p L = CO, P(OC 6 H 5 ) 3 , P(C 6 H 5 ) 3 ) the inductive (σ 1 ) and resonance (σ o R ) constants of the π-C 5 H 5 Fe(CO)(L) substituents have been determined. An inductive interaction within the iron—aryl bonding has been found to prevail. The 31 P chemical shifts have been measured for π-C 5 H 5 Fe(CO)(L′)Ar complexes (L′ = different phosphorus ligands).