Germanium(iii) corrole complex: reactivity and mechanistic studies of visible-light promoted N–H bond activations

Abstract

The [(TPFC)Ge(TEMPO)] (1, TPFC = tris(pentafluorophenyl)corrole, TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl) complex was characterized by X-ray diffraction and spectroscopic studies. EPR studies indicate that the weak Ge–O bond in 1 is photo-cleaved to form a tetra-coordinated germanium(III) radical, [(TPFC)Ge(III)]˙. DFT calculations show that the spin density on the germanium center in [(TPFC)Ge(III)]˙ has a significant s character. Under visible-light irradiation, 1 reacts rapidly with ammonia, primary/secondary aliphatic amines and aniline to produce (TPFC)Ge–NR¹R² (R¹R² = HH, HⁿPr, HⁱPr, H^tBu, HPh, Et₂, ⁱPr₂) complexes in high yields (65–95%).