Molybdenum corroles

XPS data have been also reported in the past [33] for chromium and molybdenum corrolates and discussed with respect to analogous porphyrinates. 

Cyclic voltammetry and controlled-potential electrolysis are the techniques that have been used to investigate the electrochemistry of oxo-chromium and oxo-molybdenum corrolates. The data have been related to those obtained for similar porphyrin complexes. Redox potentials are reported in Table 17. 

The large differences in metal-centered redox potentials between chromium and molybdenum have been attributed to the existence of a greater interaction between the Cr dxy orbital and the a and/or k orbitals of the corrole ligand. Such interaction would in fact reduce d electron density at the metal. Another factor considered to cause the potential difference has been a strong covalent interaction between chromium and N-donor ligands. 

Formally, pentavalent neutral metallocorroles have been prepared by Murakami and coworkers.The first of these was the oxomolybdenum(V) corrole derivative 2.179. ° This complex was prepared by heating free-base corrole 2.82 with molybdenum pentachloride in oxygen-free decalin (Scheme 2.1.56). Alternatively, molybdenum hexacarbonyl (Mo(CO)e) could be used as the metal source. In both cases, oxidation to the oxomolybdenum complex 2.179 was believed to occur during workup (involving chromatography on neutral alumina followed by recrystallization). In this way, complex 2.179 was isolated in c. 40% yield. Similar yields of the oxochromium(V) complex 2.180 could be achieved via the reaction of 2.82 with anhydrous chromium(II) chloride in DMF. Here too, spontaneous oxidation during workup was used to afford the formally pentavalent oxo-complex 2.180. 

Luobeznova I, Raizman M, Goldberg I, Gross Z (2006) Synthesis and full characterization of molybdenum and antimony corroles and utilization of the latter complexes as very efficient catalysts for highly selective aerobic oxygenation reactions. Inorg Chem 45 386-394... 

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