A novel linear chain iron complexes with the repeating unit of $[Fe_2(taea)_2(μ-O)(μ-RC(COO)_2)]^{2+}$(1; R is $(CH_3S)_2C$= ; taea, tris(2-aminoethyl)amine, 2; R is $Et_2$) has been prepared and characterized by elemental analysis, IR, UV/VIS, NMR and single crystal X-ray crystallography. IR spectrum of 1 has a strong new absorption at $852 cm^{-1}$, which is characteristic of the $v_a$(Fe-O-Fe). A peak at $406 cm^{-1}$ which is symmetric stretching of Fe-O-Fe is observed in Raman spectrum. Also, electronic spectrum band observed at near 300 nm is assigned to oxo-to-Fe charge-transfer transitions. X-ray structure analysis reveals that the iron atoms are bridged by a single oxo ligand and these structural units are linked linearly via a carboxylate group in $RC(COO)_2$ ligand.
$Q_3[Fe(mtm)_3]$(3,Q=$Ph_4P$;4,$Et_4N$) which may have three dimentionality through thioether of mtm is prepared and studied by spectroscopy. The details of properties of ferric compounds is descrived in the next section.
