Synthesis and stereochemical properties of chiral square complexes of iron(II).
The hexadentate, and ditopic ligand 2,5-bis([2,2']bipyridin-6-yl)pyrazine yields a chiral, tetrameric, square-shaped, self-assembled species upon complexation with Fe2+ ions. The racemate of this complex was resolved with antimonyl tatrate as the chiral auxiliary. The purity of the enantiomer was determined by NMR spectroscopy, by using a chiral, diamagnetic shift reagent, and by circular dichroism (CD). The CD spectrum was also calculated by time-dependent density functional theory, and the correlation that was found between CD spectrum and configuration was confirmed by X-ray cristallography. When a "chiralised" version of the ligand was used instead, the corresponding iron complex was obtained in diastereomerically pure form.
Bark
Thomas
T
Department of Chemistry, University of Fribourg, Pérolles, 1700 Fribourg, Switzerland.
von Zelewsky
Alexander
A
Rappoport
Dmitrij
D
Neuburger
Markus
M
Schaffner
Silvia
S
Lacour
Jérôme
J
Jodry
Jonathan
J