Chiral Recognition and Stereoselective Reduction of Horse Ferricytochrome c by Optically Active Iron(ll) Complexes

Abstract

The reduction of ferricytochrome c with the chiral complexes [Fe(alamp)] (alamp = N,N'-[(pyridine-2,6-diyl)bis(methylene)]bis[(R)- or (S)-alanine]) and [Fe(promp)] (promp = N,N'-[(pyridine-2,6-diyl)bis(methylene)]bis[(R)- or (S)-proline] is moderately stereoselective. The temperature dependence of the stereoselectivity shows ΔΔH^#_Δ-Λ/ΔΔS^#_Δ-Λ compensation behaviour giving crossing Eyring plots at 28° and 36° for alamp and promp, respectively. The activation parameters of the two ligands show inverted signs indicating that electron transfer with the corresponding Fe^ll complexes probably does not occur in an identical geometrical environment.