Formation and stabilization of five-coordinate iron(II) verdoheme analogues by axial weakly coordinating anion ligation. X-ray crystal structures of [(OEOPFe)2O](X)2 (X=AsF6, SbF6)

Isolation and characterization of new heme analogues with weakly coordinating anions: Formation of monoimidazole complex, OEPFe(Im)(SbF6)

The effects of weakly coordinating anions, BF 4, AsF 6 and SbF 6, as axial ligands on the formation and coordination chemistry of heme analogues have been examined. Three new five-coordinate and stable iron(III) heme analogues, OEPFeX , where OEP is the dianion of octaethylporphyrin and X = BF 4, AsF 6 and SbF 6, have been isolated. The compounds have been characterized by different spectroscopic methods as well as elemental analysis. 1 H NMR spectroscopy and magnetic moment measurements show that the OEPFeX are paramagnetic and iron is five-coordinate. In addition, monoimidazole ferric-porphyrin complex, OEPFe ( Im )( SbF 6) has been prepared in solution, by starting with OEPFe ( SbF 6). The electrochemical properties of OEPFeX ( X = BF 4, AsF 6, SbF 6) have been studied by cyclic voltammetry and differential pulse polarography.