The Mechanism of E–H (E = N, O) Bond Activation by a Germanium Corrole Complex: A Combined Experimental and Computational Study

Abstract

(TPFC)­Ge­(TEMPO) (<b>1</b>, TPFC = tris­(pentafluorophenyl)­corrole, TEMPO^• = (2,2,6,6-tetramethylpiperidin-1-yl)­oxyl) shows high reactivity toward E–H (E = N, O) bond cleavage in R₁R₂NH (R₁R₂ = HH, ^<i>n</i>PrH, ^<i>i</i>Pr₂, Et₂, PhH) and ROH (R = H, CH₃) under visible light irradiation. Electron paramagnetic resonance (EPR) analyses together with the density functional theory (DFT) calculations reveal the E–H bond activation by [(TPFC)­Ge]⁰(<b>2</b>)/TEMPO^• radical pair, generated by photocleavage of the labile Ge–O bond in compound <b>1</b>, involving two sequential steps: (i) coordination of substrates to [(TPFC)­Ge]⁰ and (ii) E–H bond cleavage induced by TEMPO^• through proton coupled electron transfer (PCET)