Chromium corroles

Chromium corroles have been isolated as 6-coordinate Cr(III) and 5-coordinate Cr(IV/V/VI) oxo, nitrido, and imido complexes. The synthesis of Cr(tpfc)(py)2 (py = pyridine), which is oxidized to (oxo)Cr(tpfc) on standing in aerated solution, was reported in 2001 [78]. Cr(tfpc)(0) could be reduced by cobaltocene to give... 

Meier-Callahan AE, di Bilio AJ, Simkhovich L, Mahammed A, Goldberg I, Gross Z, Gray HB (2001) Chromium corroles in four oxidation states. Inorg Chem 40 6788-6793... 

Edwards NY, Eikey RA, Loring MI, Abu-Omar MM (2005) High-valent imido complexes of manganese and chromium corroles. Inorg Chem 44 3700-3708... 

Mahammed A, Gray HB, Meier-Callahan AE, Gross Z (2003) Aerobic oxidations catalyzed by chromium corroles. J Am Chem Soc 125 1162-1163... 

Meier-Callahan, A.E., A.J. Di Bilio, L. Simkhovich, A. Mahammed, 1. Goldberg, H.B. Gray etal. (2001). Chromium corroles in four oxidation states. Inorg. Chem. 40, 6788-6793. 

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

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. 

Fig. 6 The varied reactivity of chromium and manganese corrole complexes...

Meier-Callahan AE, Gray HB, Gross Z (2000) Stabilization of high-valent metals by corroles oxo[tris(pentafluorophenyl)corrolato]chromium(V). Inorg Chem 39 3605-3607... 

Golubkov G, Gross Z (2003) Chromium(V) and chromium (VI) nitrido complexes of tris (pentafluorophenyl)corrole. Angew Chem Int Ed 42 4507-4510... 

Chromium complexes acetylacetone complex formation, 386 exchange reactions, 380 amidines, 276 bridging ligands, 198 chelating ligands, 203 carbamic acid, 450 paddlewheel structure, 451 carboxylic acids, 438 trinuclear, 441 corroles, 874... 

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