Structure and Photochemistry of Manganese Porphyrin Sulfate Complexes

Kenneth S. Suslick, Randall A. Watson, Scott R. Wilson

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New sulfate and hydrogen sulfate complexes of metalloporphyrins have been synthesized and crystallographically characterized and their photochemistry examined. Irradiation of [Mn(TPP)]2(SO4) and Mn(TPP)(OSO3H) (where TPP = 5,10,15,20-tetraphenylporphyrinate(2-)) produces MnII(TPP) quantitatively, with quantum yields of 7.1 × 10-4 and 9.8 × 10-4, respectively. In contrast to other manganese oxoanion complexes, metal-oxo species are not formed and oxidation of hydrocarbons does not occur. The X-ray crystal structures of [Mn(TPP)]2(SO4)·2C6H6·½C5H12·½H2O and Mn(TPP)(OSO3H)·CH2Cl2 show stereochemistry similar to that of the analogous iron complexes. In the sulfate complex [Mn(TPP)]2(SO4), the average Mn-pyrrole N distance is 2.008 Å in both rings, with the metal displaced above the mean plane of the nitrogen atoms by 0.19 and 0.22 Å for Mn(1) and Mn(2), respectively. The sulfate ion is coordinated in an unidentate fashion. In Mn(TPP)(OSO3H) the average Mn-pyrrole nitrogen distance is 1.991 Å with the metal 0.23 Å above the mean plane of the nitrogen atoms. The hydrogen sulfate ion is coordinated through one of the oxygens, with Mn-O = 2.078 Å. Crystal data for Mn(TPP)(OSO3H)·CH2Cl2: space group [formula omited], a= 13.782 (8) Å, b = 13.861 (6) Å, c = 13.504 (8) Å, a = 108.57 (4)°, β = 118.77 (4)°, γ = 60.43 (4)°, V = 1956 (3) Å3, and Z = 2. Crystal data for [Mn(TPP)]2(SO4)·2C6H6·½C5H12·½H2O at -25 °C: space group [formula omited], a = 14.585 (16) Å, b = 21.949 (10) Å, c = 13.142 (6) Å, a = 90.11 (4)°, β = 104.65 (6)°, γ = 96.47 (5)°, V = 4042 (9) Å3, and Z = 2.

Original languageEnglish (US)
Pages (from-to)2311-2317
Number of pages7
JournalInorganic Chemistry
Issue number10
StatePublished - May 1 1991

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry


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