Intramolecular Direct Oxygen Transfer from Oxoferryl Porphyrin to a Sulfide Bond

A 1:1 supramolecular complex (met-hemoCD) of 5,10,15,20-tetrakis­(4-sulfonatophenyl)­porphyrinatoiron­(III) (Fe^IIITPPS) with a per-<i>O</i>-methylated β-cyclodextrin dimer having a −SCH₂PyCH₂S– (Py = pyridin-3,5-diyl) linker (Py3CD) reacted rapidly with hydrogen peroxide or cumene hydroperoxide in an aqueous solution forming two types of hydroperoxo or alkylperoxo intermediates, ROO-Fe^III(OH^–)­PCD and ROO-Fe^III(Py)­PCD, which underwent rapid homolysis to the corresponding ferryloxo species, namely, OFe^IV(OH^–)­PCD and OFe^IV(Py)­PCD, respectively. For the OFe^IV(OH^–)­PCD species, the iron-oxo oxygen facing the linker gradually transferred to the nearby sulfide bond on the linker, forming the sulfoxidized Py3CD (Py3CD-O)/Fe^IITPPS complex, which then bound dioxygen in air forming an oxy-ferrous complex, O₂-Fe^IITPPS/Py3CD-O. In contrast, the OFe^IV(Py)­PCD species, in which the iron-oxo oxygen was located on the opposite side of the sulfide bond on the linker across the porphyrin ring, was reduced to the resting state (met-hemoCD) by the surroundings without any oxidation of the Py3CD linker