Seminars

X-ray and Neutron Diffraction Studies on Iron(III) Porphyrin Derivatives

by Brenda A. Dougan, University of Knoxville, Tennessee, USA

Europe/Berlin
Bldg. 25b, room 109

Bldg. 25b, room 109

Description
Metals such as iron play important roles in biological systems.1 Fe-containing hemes are involved, e.g., in O2 transport (respiration) and catalytic reactions. In these metalloproteins, Fe ions are bound to porphyrin ligands to form complexes known as hemes. We have studied the metal-containing biological species [FeTPP(HIm)2]Cl (TPP = tetraphenylporphyrin; HIm = 1H-imidazole) and FeTPPCl by X-ray and neutron diffraction. The two complexes were collected at 293, 143, and 20 K by single-crystal X-ray diffraction. Neutron structures have been obtained. The X-ray and neutron diffraction results give insightful knowledge on their unique structural behavior. The synthesis and X-ray structures of their novel deuterated analogs, FeTPPCl-d28 and [FeTPP(DIm)2-d36]Cl, will be discussed. In addition, the magnetic properties of [FeTPP(HIm)2]Cl is directly probed by using spin density studies. The X-ray, neutron, and spin density studies will be presented. 1 S.J. Lippard, J.M. Berg, Principles of Bioinorganic Chemistry, University Science Press, CA, 1994.