Chemistry Letters, Vol.35, No.2, 156-157, 2006
Anomalous (CNMR)-C-13 chemical shifts of high-spin saddle shaped manganese(III) octaethyltetraphenylporphyrin complexes
NMR spectra of highly saddled Mn(III) porphyrinates such as Mn(OETPP)(CD3OD)(2)(+) have been measured. The extraordinarily upfield shifted meso-C-13 signals, which reach as much as -492 ppm at 298 K, are ascribed to the d(x2-y2)-a(2u), d(xy-a1u), and d(pi)-3e(g) interactions, the former two of which occur only when the porphyrin ring is saddled.