Halogen Transfer to Carbon Radicals by High-Valent Iron Chloride and Iron Fluoride Corroles

High-valent iron halide corroles were examined to determine their reactivity with carbon radicals and their ability to undergo radical rebound-like processes. Beginning with Fe­(Cl)­(ttppc) (1) (ttppc = 5,10,15-tris­(2,4,6-triphenylphenyl)­corrolato^3–), the new iron corroles Fe­(OTf)­(ttppc) (2), Fe­(OTf)­(ttppc)­(AgOTf) (3), and Fe­(F)­(ttppc) (4) were synthesized. Complexes 3 and 4 are the first iron triflate and iron fluoride corroles to be structurally characterized by single crystal X-ray diffraction. The structure of 3 reveals an Ag^I–pyrrole (η²–π) interaction. The Fe­(Cl)­(ttppc) and Fe­(F)­(ttppc) complexes undergo halogen transfer to triarylmethyl radicals, and kinetic analysis of the reaction between (p-OMe-C₆H₄)₃C• and 1 gave k = 1.34(3) × 10³ M^–1 s^–1 at 23 °C and 2.2(2) M^–1 s^–1 at −60 °C, ΔH^⧧ = +9.8(3) kcal mol^–1, and ΔS^⧧ = −14(1) cal mol^–1 K^–1 through an Eyring analysis. Complex 4 is significantly more reactive, giving k = 1.16(6) × 10⁵ M^–1 s^–1 at 23 °C. The data point to a concerted mechanism and show the trend X = F^– > Cl^– > OH^– for Fe­(X)­(ttppc). This study provides mechanistic insights into halogen rebound for an iron porphyrinoid complex.