Structural and 57Fe-Mössbauer characterization of mononuclear ferrous and ferric pyrazole complexes

The reactions of FeX3 (X = Cl and Br) and pz∗H (pz∗H = pyrazole, or substituted pyrazole) in CH2Cl2 have led to three types of mononuclear complexes: mer-[FeX3(pz∗H)3], trans-[FeX2(pz∗H)4]− and trans-[FeX2(pz∗H)4]. The latter type, containing FeII-centers results from spontaneous reduction of the FeIII starting material. The X-ray crystal structures of eleven such complexes and the 57Fe-Mössbauer spectra of three of them are reported.

Mononuclear, six-coordinate Fe(II)- and Fe(III)-complexes of trans and mer geometry have been prepared with pyrazole and halogen ligands.Figure optionsDownload as PowerPoint slide