W. Ryan Osterloh, Jeanet Conradie, Abraham B. Alemayehu, Abhik Ghosh* and Karl M. Kadish*,
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引用次数: 2
Abstract
We have revisited the electrochemistry of metallocorrole dimers with low-temperature cyclic voltammetry and UV–visible–NIR spectroelectrochemistry, with the aim of determining the sites of the redox processes undergone by these compounds. The systems studied include the metal–metal triple-bonded complexes {Ru[TpOMePC]}2 and {Os[TpOMePC]}2 and the metal–metal quadruple-bonded complex {Re[TPC]}2, where TpOMePC and TPC refer to trianionic meso-tris(p-methoxyphenyl)corrole and meso-triphenylcorrole ligands. For all three compounds, the first oxidation potentials are found at 0.52 ± 0.04 V vs SCE in CH2Cl2/0.1 M TBAP and are accompanied by major changes in the optical spectra, especially the appearance of broad, low-energy bands, suggesting macrocycle-centered oxidation in each case. In contrast, the reduction potentials span an 800 mV range, occurring at E1/2 = −0.52 V for {Re[TPC]}2, −0.81 V for {Ru[TpOMePC]}2, and −1.32 V for {Os[TpOMePC]}2, with more modest changes in the optical spectra, implying a significant metal-centered character in the reduction process. Density functional theory (DFT) calculations largely (but not entirely) bear out these expectations. The combined experimental and theoretical data indicate that one-electron addition to the Re dimer involves the Re–Re δ* LUMO, while one-electron addition to the Ru dimer largely involves the Ru–Ru π* LUMO. In contrast, the calculations suggest that one-electron reduction of the Os dimer occurs largely on the corrole ligands, a phenomenon attributed to the relativistic destabilization of the Os–Os π* MOs.
期刊介绍:
ACS Organic & Inorganic Au is an open access journal that publishes original experimental and theoretical/computational studies on organic organometallic inorganic crystal growth and engineering and organic process chemistry. Short letters comprehensive articles reviews and perspectives are welcome on topics that include:Organic chemistry Organometallic chemistry Inorganic Chemistry and Organic Process Chemistry.