Porphyrins and Other Model Systems

The formulation of the product from the reaction of [(TPP)Fe J with CCI4 in the presence of excess reducing agent as the first dichlorocarbene-transition metal complex, has now been amply confirmed by a crystal structure analysis. The complex is [Fe(TPP)CCla(H20)] with /rawj-carbene and water ligands essentially colinear and (Fe—C) = 1.83(3) A. 

Direct aerial oxidation of cobalt(ii) in the presence of acetone, acetonitrile, and malononitrile has been used for the first time in the porphjrrin series to generate organocobalt(m) porphyrin derivatives. The acetonyl species [Co-(TPP)CHaCOCH3] was characterized by an JlT-ray crystal structure and found to have (Co—C)=2.028 A. The complexes are stable in solution and apparently fairly stable to light. A further novel alkylation of prophyrins involves electro- 

Further data have been reported on the reactions of cobalt(m) porphyrins with diazoalkanes as a route to vinyl- or halomethyl-cobalt(m) porphyrin complexes. The reaction pathway, involving probable insertion of an initially generated carbene fragment into the Co—N bond is also discussed.  

The photochemistry of cobalt-methyl derivatives of (3) and (4) has been studied and homolysis threshold energies determined. Compound (3) particularly 

Boucly, J. Devynck, M. Perree-Fauvet, and A. Gaudemer, /. Organometallic Chem., 1978, 149,65. 

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