(5,10,15,20-Tetra(4-pyridil)porphinato)manganese(III) acetate modified by four μ3-oxo-triruthenium acetate clusters: synthesis, characterization, electrochemical behavior and catalytic activity

A novel supermolecule constituted by four μ3-oxo-triruthenium acetate clusters coordinated to manganese(III)-meso-tetra(4-pyridil)porphyrin acetate ([MnTPyP]CH3COO) has been synthesized. Characterization has been performed by UV–Vis and 1H NMR spectroscopy. The electrochemical behavior (cyclic voltammetry and spectroelectrochemistry) in N,N′-dimethylformamide has been analyzed in terms of five redox processes: three related to peripheral clusters (RuIV,III,III/RuIII,III,III/RuIII,III,II/RuIII,II,II) and two centered on the Mn–porphyrin core (MnIIIP/MnIIP/MnIIP2−). A direct comparison has been performed between MnTCP and MnTPyP as catalysts for the cyclooctene and cyclohexane oxidation reactions. The improved selectivity exhibited by the supramolecular catalyst for cyclohexane oxidation has been ascribed to electronic effects on the oxomanganese(V) porphyrin species induced by the four peripheral clusters, in the formal RuIVRuIIIRuIII oxidation state.