Metallkomplexe mit Tetrapyrrol-Liganden, XIX [1]. Synthese und elektrochemische Charakterisierung der Kohlenmonosulfid-Metalloctaethylporphyrine mit Eisen(II) oder Osmium(II) im Zentrum. Ein Beitrag zur "Bathochromie-Regel" / Metal Complexes with Tetrapyrrole Ligands, XIX [1]. Synthesis and Electrochemical Characterization of Thiocarbonyl Metallooctaethylporphyrins with Iron(II) or Osmium(II) in the Center. A Contribution to the "Rule of Bathochromism"
Open Access
- 1 December 1978
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 33 (12) , 1371-1380
- https://doi.org/10.1515/znb-1978-1201
Abstract
The preparation and spectroscopic characterization of thiocarbonyl metalloporphyrins M(OEP)CS(L') (e.g. 2e: M = Fe, L' = Py, 1e: M = Os, L' = Py** are described. Especially noteworthy is the existence of a pentacoordinate, diamagnetic, air-stable heme Fe(OEP)CS (2f: M = Fe, no L′). A linear correlation of the α-band frequencies (expressed as ϋa) in the optical spectrum and the metal(II/III) redox potentials (E1/2) taken from cyclic voltammetry experiments suggests (Abb. 3) that in complexes of the type M(OEP)LL' (1,2) λa is bathochromically shifted as the π-acceptor capacity of L increases (“Rule of Bathochromism”). The strong π-acceptor capacity of carbon monosulphide renders the attack of dioxygen to the thiocarbonyl heme unfavourable; O2 and CS seem to be comparable in their π-acceptor strength.Keywords
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