Synthesis and structure of iron(III) complexes with a new ligands based on Girard’s reagent
作者:M. D. Revenko、P. N. Bourosh、O. V. Palamarchuk、J. Lipkowski、M. Gdaniec、Yu. A. Simonov
DOI:10.1134/s0036023609100143
日期:2009.10
Condensation of 5-bromosalicylaldehyde with Girard's reagent T yields a new ligand in the form of a salt, 5-bromosalicylaldehyde (carboxymethyl)trimethylammonium chloride hydrazone (5-BrH(2)SalGT)Cl (I). Ligand I is readily soluble in water and reacts with iron chloride to give the complex [Fe(5-BrSalGT)Cl-2] (II). Treatment of II with KCNS leads to the compound [Fe(5-BrSalGT)(NCS)(2)(H2O)] (III). At any ratio of the initial reagents, only complexes with the ratio metal: ligand = 1: 1 are isolated. Comparison of the structural data for compounds I-III shows that ligand I is deprotonated in the course of complex formation and is coordinated in the anionic form. Its conformational rearrangement is minimal and involves only a change in the orientation of the terminal group N(CH3)(3). In complexes II and III, ligand I is coordinated to the metal ion through the ONO donor atoms. The structures of the complexes with different acido ligands are significantly different. Although the complexes contain each two inorganic anions, their coordination polyhedra differ from each other. In II, the iron atom is at the center of a trigonal bipyramid, whereas in III the iron atom has a tetragonal-bipyramidal environment due to the extra coordination of a water molecule. In both complexes, the iron atom is in the high-spin state: at room temperature, mu(eff) is 5.86 and 5.81 mu(B) for II and III, respectively. Complexes II and III are ordinary paramagnets down to 2 K.