M chloroperoxybenzoic acid

meso-Tetramesitylporphyrin was purchased from Mid-Century Chemicals. Chromium(ii) chloride (CrCl₂), chromium hexacarbonyl, and m-chloroperoxybenzoic acid (mCPBA) were purchased from Sigma-Aldrich. Chloroform was distilled from P₄O₁₀, deacidified by passing through a two-layered column of dry K₂CO₃ and dry basic alumina (Activity I), and stored over activated 4 Å molecular sieves. meso-Tetraphenylporphyrin^{22 (link)} and meso-triphenylcorrole^{23 (link)} were prepared according to literature procedures. Chromium(iii) meso-tetramesitylporphyrin chloride,^{24 (link)} Cr^III[TMP]Cl, and chromium(iii) meso-tetraphenylporphyrin chloride,^{25 (link)} Cr^III[TPP]Cl (1), were prepared under aerobic conditions using protocols due to Adler et al.^{26 (link)} Chromium(iv)-oxo meso-tetramesitylporphyrin, Cr^IV[TMP]O (2), was prepared as previously described,⁴⁴ with the following modifications: Cr^III[TMP]Cl and mCPBA (4 equiv.) were stirred in dry, deacidified CHCl₃ under argon for 15 min. Dry K₂CO₃ was added to the solution and after stirring for 3 min, the suspension was placed on a basic alumina (Activity I) column and flash-chromatographed with dry, deacidified CHCl₃ under argon, whereupon Cr^IV[TMP]O eluted as the first red band. Chromium(v)-oxo meso-triphenylcorrole was prepared as previously described using a method similar to that used for the tris(pentafluorophenyl)corrole analogue.^{27 (link)}