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) (<b>1</b>) (ttppc = 5,10,15-tris­(2,4,6-triphenylphenyl)­corrolato^3–), the new iron corroles Fe­(OTf)­(ttppc) (<b>2</b>), Fe­(OTf)­(ttppc)­(AgOTf) (<b>3</b>), and Fe­(F)­(ttppc) (<b>4</b>) were synthesized. Complexes <b>3</b> and <b>4</b> are the first iron triflate and iron fluoride corroles to be structurally characterized by single crystal X-ray diffraction. The structure of <b>3</b> 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 (<i>p</i>-OMe-C₆H₄)₃C• and <b>1</b> gave <i>k</i> = 1.34(3) × 10³ M^–1 s^–1 at 23 °C and 2.2(2) M^–1 s^–1 at −60 °C, Δ<i>H</i>^⧧ = +9.8(3) kcal mol^–1, and Δ<i>S</i>^⧧ = −14(1) cal mol^–1 K^–1 through an Eyring analysis. Complex <b>4</b> is significantly more reactive, giving <i>k</i> = 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.