Synthesis and Electrochemical Studies of a Series of Fluorinated Dodecaphenylporphyrins

Karl M. Kadish; Eric Van Caemelbecke; Francis D'Souza; Min Lin; Daniel J. Nurco; Craig J. Medforth; Timothy P. Forsyth; Bénédicte Krattinger; Kevin M. Smith; Shunichi Fukuzumi; Ikuo Nakanishi; John A. Shelnutt

doi:10.1021/ic9811695

Synthesis and Electrochemical Studies of a Series of Fluorinated Dodecaphenylporphyrins

Inorg Chem. 1999 May 3;38(9):2188-2198. doi: 10.1021/ic9811695.

Authors

Karl M. Kadish¹, Eric Van Caemelbecke, Francis D'Souza, Min Lin, Daniel J. Nurco, Craig J. Medforth, Timothy P. Forsyth, Bénédicte Krattinger, Kevin M. Smith, Shunichi Fukuzumi, Ikuo Nakanishi, John A. Shelnutt

Affiliation

¹ Department of Chemistry, University of Houston, Houston, Texas 77204, Department of Chemistry, University of California, Davis, California 95616, Department of Material and Life Science, Osaka University, Suita, Osaka 565-0871, Japan, Materials Theory and Computational Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-1349, and Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131.

PMID: 11671005
DOI: 10.1021/ic9811695

Abstract

Dodecaphenylporphyrins with varying degrees of fluorination of the peripheral phenyl rings (F(x)()DPPs) were synthesized as model compounds for studying electronic effects in nonplanar porphyrins, and detailed electrochemical studies of the chloroiron(III) complexes of these compounds were undertaken. The series of porphyrins, represented as FeDPPCl and as FeF(x)()DPPCl where x = 4, 8 (two isomers), 12, 20, 28, or 36, could be reversibly oxidized by two successive one-electron transfer steps in dichloromethane to give pi-cation radicals and pi-dications, respectively. All of the compounds investigated could also be reduced by three electrons in benzonitrile or pyridine. In benzonitrile, three reversible reductions were observed for the unfluorinated compound FeDPPCl, whereas the FeF(x)()DPPCl complexes generally exhibited irreversible first and second reductions which were coupled to chemical reactions. The chemical reaction associated with the first reduction involved a loss of the chloride ion after generation of [Fe(II)F(x)()DPPCl](-). The second chemical reaction involved a conversion between the initially generated Fe(II) porphyrin pi-anion radical and the final Fe(I) porphyrin reduction product. In pyridine, three reversible one-electron reductions were observed with the second reduction affording stable Fe(II) porphyrin pi-anion radicals for all of the complexes investigated.