Mössbauer effect study of iron(III)-inidazolidine nitroxyl-free radical ligand complex

A new complex, [Fe(acac)L₂], bearing inidazolidine nitroxyl-free radical ligand (L^-) was recently synthesised for biological studies. It proved to be biologically active against African sleeping sickness, plasmodium falciparum (malaria), leishmaniasis and chaga disease causative agents. Three ESR well resolved peaks indicated the presence of a free (unpaired) and chemically active electron in the complex. The structural complex ferric iron was found at the centre of two electric gradient whose the biggest is suggested to be initiated by the unpaired charge. No distinction between different cis isomers could be made.