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Synthesis and Characterization of a μ‐Oxo‐Bridged Diferric Complex: An Attempt to Influence the Configuration by Changing the Spacer
Author(s) -
Aschenbrenner Martin,
Stammler Anja,
Bögge Hartmut,
Glaser Thorsten
Publication year - 2018
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201800275
Subject(s) - steric effects , crystallography , bond length , chemistry , ligand (biochemistry) , mössbauer spectroscopy , octahedron , coordination sphere , crystal structure , diamine , single crystal , stereochemistry , polymer chemistry , biochemistry , receptor
The μ‐oxo‐bridged diferric complex [(susan Pr ){Fe III Cl(μ‐O)Fe III Cl}](ClO 4 ) 2 was synthesized and characterized by single‐crystal X‐ray diffraction, elemental analysis, FT‐IR, UV/Vis/NIR, and Mössbauer spectroscopies as well as magnetic and electrochemical measurements. The properties are compared to the corresponding values for the complex [(susan){Fe III Cl(μ‐O)Fe III Cl}](ClO 4 ) 2 , which exhibits a central ethylene spacer, whereas [(susan Pr ){Fe III Cl(μ‐O)Fe III Cl}](ClO 4 ) 2 has a propylene spacer. Both complexes exhibit a trans configuration of the two terminal chloride ligands. This configuration induces more steric demand in the case of the propylene spacer, which results in a rotation of the two octahedral units along the Fe–(μ‐O)–Fe axis and a tilting of the Fe–N bonds of the diamine spacer. The iron bond lengths are only slightly elongated by the steric demand of the propylene spacer, which is reflected by almost no change in the Mössbauer spectrum. However, the UV/Vis/NIR spectra show a stronger ligand field for [(susan Pr ){Fe III Cl(μ‐O)Fe III Cl}](ClO 4 ) 2 . The slightly longer iron bond lengths result in less electron donation, which is reflected by an anodic shift of 120 mV for the oxidation of the complex. This comparison provides more information on the variation of the properties of the diferric complexes by slight changes in the second coordination sphere.