SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF AN IRON(II) COMPLEX WITHBIIMIDAZOLE AMINE TRIDENTATE LIGANDS/

The novel iron(ll) [FeL(2)]Cl1.3Br0.7 complex has been prepared, where L = bis[(1-methylimidazol-2-yl)methyl]amine. It crystallizes in the m onoclinic system, space group P2(1)/c, with Z=4, a=9.328(4) Angstrom, b=9.174(4) Angstrom, c=19.389(9) Angstrom, and beta=97.90(3)degrees, T he structure consists of mononuclear cations [FeL(2)](2+) separated by X(-) (Cl/Br) anions and DMF molecules of crystallization. The central iron is in a distorted octahedral environment provided by the two imi dazoles and the amine nitrogen atoms of each ligand. Each halide ion i s involved in six hydrogen bonds. The iron(ll) high-spin S=2 ground sl ate is confirmed by the Mossbauer, magnetic susceptibility, EPR and IH NMR data, The Mossbauer spectrum is characterized by the presence of two distinct doublets, assigned to the two components of [FeL(2)]Cl1.3 Br0.7, namely 32% of [FeL(2)]Cl-2 and 68% of [FeL(2)]ClBr. This hetero geneity is explained by anion effects, through the hydrogen-bonding ne twork, upon the electric field gradient at the ferrous site.