Spectra and structure of iron(III) complexes with carbamide derivatives containing an acetyl group

Abstract

Equilibria of complex formation reactions of Fe III in aqueous solutions with CH 3CONHCONH 2 and CH 3CONHCONHCH 3 were investigated by the UV spectral method. The formation of complexes of [Fe(H 2O) 6- n L n ] +3 (where n = 1, 2) has been established and their stability constants determined. The following crystalline complexes have been obtained: [Fe(CH 3CONHCONH 2 ) 3 ]Cl 3 and [Fe(CH 3CONHCONHCH 3) 3]Cl 3, and their structures investigated using IR and NMR spectra. Results suggest that they are six-membered ring structures. The influence of the polar effects of substituents on the stability of iron(III) complexes with acetylcarbamides has been discussed and mesomeric effects have been shown to dominate inductive effects and work in opposite directions.