New insights into the chemistry of di- and trimetallic iron dithiolene derivatives. Structural, M?ssbauer, magnetic, electrochemical and theoretical studies

摘要

Reaction of Fe_3(CO)_(12) with 1,2-dithiolene HSC_6H_2Cl_2SH affords a mixture of complexes Fe_2(CO)_6(μ-SC_6H_2Cl_2S) 1, Fe_2(SC_6H_2Cl_2S)_4 2 and Fe_3(CO)_7(μ_3-SC_6H_2Cl_2S)_2 3. In the course of the reaction the trimetallic cluster 3 is first formed and then converted into the known dinuclear compound 1 to afford finally the neutral diiron tetrakis(dithiolato) derivative 2. Compounds 2 and 3 have been studied by M?ssbauer spectroscopy, X-ray crystallography and theoretical calculations. In compound 2 the metal atoms are in an intermediate-spin Fe~(III) state (S_(Fe) = 3/2) and each metal is bonded to a bridging dithiolene ligand and a non-bridging thienyl radical (S = 1/2). Magnetic measurements show a strong antiferromagnetic coupling in complex 2. Cyclic voltammetry experiments show that the mixed valence trinuclear cluster 3 undergoes a fully reversible one electron reduction. Additionally, compound 3 behaves as an electrocatalyst in the reduction process of protons to hydrogen.