A symmetric oxo-centered trinuclear chloroacetato bridged iron(III) complex: Structural, spectroscopic and electrochemical studies

An oxo-centred, carboxylate bridged trinuclear iron(III) complex [Fe3(μ3-O)(O2CCH2Cl)6(H2O)3]ClO4·9H2O (1·9H2O) has been synthesized and characterized on the basis of X-ray crystallography, elemental analysis, cyclic voltammetric, UV–vis and IR spectroscopic techniques. Molecular structure has been established by X-ray diffraction analysis and reveals that the complex 1·9H2O crystallizes in the rhombohedral space group R3 with a = 18.0070(6) Å, b = 18.0070(6) Å, c = 9.7962(5) Å, α = β = 90.00° and γ = 120.00°. In the highly symmetric trinuclear structure, three iron(III) atoms occupy vertices of equilateral triangle and exhibits a quasi-reversible one-electron reduction at E½ = +0.337 V vs Ag/AgCl (ΔEp = 0.079 V) due to the [Fe3(μ3-O)(O2CCH2Cl)6(H2O)3]+/[Fe3(μ3-O)(O2CCH2Cl)6(H2O)3] couple. In addition, ascending difference between cathodic and anodic peak potentials (ΔEp) with the increasing scan rate confirmed the reduction wave to be quasi-reversible.

► Oxo-centred, carboxylate-bridged trinuclear iron(III) complex has been synthesized.
► Molecular structure has been established by X-ray crystallography.
► Iron atoms, in highly symmetric structure, occupy vertices of equilateral triangle.
► IR spectral study confirms the presence of bridging carboxylates.
► Cyclic volammograms represent a quasi-reversible one-electron reduction wave.