Properties of Manganese(III) Ferrocenyl-β-Diketonato Complexes Revealed by Charge Transfer and Multiplet Splitting in the Mn 2p and Fe 2p X-Ray Photoelectron Envelopes

• Published in: Molecules (Basel, Switzerland) Vol. 21; no. 11; p. 1427
• Main Authors: Buitendach, Blenerhassitt E, Erasmus, Elizabeth, Niemantsverdriet, J W Hans, Swarts, Jannie C
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 26-10-2016; MDPI AG
• Subjects: charge transfer; Electrochemistry; ferrocene; Ferrous Compounds - chemistry; manganese; Manganese - chemistry; Metallocenes; Molecular Structure; multiplet splitting; Organometallic Compounds - chemistry; Photoelectron Spectroscopy; X-ray photoelectron spectroscopy; β-diketonato complexes; multiplet splitting; ferrocene; manganese; β-diketonato complexes; X-ray photoelectron spectroscopy; charge transfer
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules21111427

A series of ferrocenyl-functionalized β-diketonato manganese(III) complexes, [Mn(FcCOCHCOR)₃] with R = CF₃, CH₃, Ph (phenyl) and Fc (ferrocenyl) was subjected to a systematic XPS study of the Mn 2p
and Fe 2p
core-level photoelectron lines and their satellite structures. A charge-transfer process from the β-diketonato ligand to the Mn(III) metal center is responsible for the prominent shake-up satellite peaks of the Mn 2p photoelectron lines and the shake-down satellite peaks of the Fe 2p photoelectron lines. Multiplet splitting simulations of the photoelectron lines of the Mn(III) center of [Mn(FcCOCHCOR)₃] resemble the calculated Mn 2p
envelope of Mn
ions well, indicating the Mn(III) centers are in the high spin state. XPS spectra of complexes with unsymmetrical β-diketonato ligands (i.e., R not Fc) were described with two sets of multiplet splitting peaks representing
and the more stable
isomers respectively. Stronger electron-donating ligands stabilize
more than
isomers. The sum of group electronegativities, Σχ
, of the β-diketonato pendant side groups influences the binding energies of the multiplet splitting and charge transfer peaks in both Mn and Fe 2p
photoelectron lines, the ratio of satellite to main peak intensities, and the degree of covalence of the Mn-O bond.