Electronic effects in octahedral π-allyliron complexes: 13C NMR spectra

¹³C NMR spectra have been studied for the three series of allyliron derivatives: (i) C₃HP₅Fe(CO)₃X (X = I, Br, Cl, ONO₂, OCOCH₃, OCOCF₃); (ii) 2-RC₃H₄Fe(CO)₃X (R = CH₃, Br; X = I, Br, Cl, ONO₂, OCOCF₃), and (iii) 1-RC₃H₄Fe(CO)₃X (R = CH₃, C₆H₅; X = Br, Cl, OCOCF₃). The spectra reveal the effect of the nature of the ligand X and substituent R on the chemical shifts of the allyl and carbonyl carbon atoms.