Iron complexes of terdentate nitrogen ligands: formation and X-ray structure of three new dicationic complexes

摘要

Dicationic iron complexes were obtained upon complexation of the ligands 6,6"-di(p-tolyl)-2,2':6',2"-terpyridine (L-1) or 2,6-bis(3-tnesitylpyrazol-1-yl)pyridine (L-2) with iron dichloride or iron trichloride. They were characterized by X-ray diffraction and FT-IR spectroscopy. Single crystal structure determinations of (L-1)(2)Fe2+(FeCl4-)(2), (L-2)(2)Fe2+FeCl42- and (L-2)(2)Fe2+(FeCl4-),(THF)(4) all show six-coordinate metal center. These complexes were obtained from (LFeCl2)-Fe-1 and (LFeCl2)-Fe-2 during recrystallization attempts. (L-1)(2)Fe2+ was shown to be a high-spin complex, whereas (L-2)(2)Fe2+ was shown to be low-spin. For (L-2)(2)Fe2+FeCl42-, two independent dications of very similar geometry but with distinctive distortion were observed by X-ray analysis. (C) 2004 Elsevier Ltd. All rights reserved.