Tuesday, 31 May 2016: 08:40
Aqua 314 (Hilton San Diego Bayfront)
The discoveries of facile syntheses of meso-aryl substituted corroles in 1999 triggered the revival of the chemistry of corroles. A variety of main group and transition metal elements were inserted into the corrole ring and some of the complexes show similar or superior properties to the related porphyrin complexes. The corrole germanium hydride showed unusual high reactivity with aldehydes, olefins and alkyl halides to form corrole germanium α-hydroxy alkyl and alkyl complexes. More importantly, the efficient photo-activation of N-H bond by TEMPO-Ge corrole complexes was observed and the mechanism was investigated based on EPR analysis. The reactivity of Sn corrole was also studied. Activation of N–H bonds with silicon and its low-valent heavier congeners typically proceeds via 2 electron pathways: i) a direct oxidative addition of the N–H bond to the low-valent metal center or ii) a metal-ligand cooperative process. Light-promoted N–H bond activation by main group element radicals has thus far rarely been encountered, but provides an attractive strategy to activate amines with lower activation energies. We observed the light-driven activation of N–H bonds by an organo-germanium corrole complex [(TPFC)Ge(TEMPO)] (TPFC = tris(pentafluorophenyl)corrole, TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl) involving a radical pathway to form germanium amides in high yields at room temperature.