Preparation and characterization of singly oxidized metalloporphyrin dimers: [M(OEP[sup [sm bullet]/2])][sub 2]SbCl[sub 6], M = Cu, Ni. Photosynthetic special pair models

The authors report the preparation and physical characterization (X-ray, UV-visible-near IR, IR, EPR, magnetic susceptibility) of two new metalloporphyrin [pi]-cation radical derivatives formally analogous to the radical cation of the photosynthetic reaction central special pair. The complexes are [M(OEP[sup [sm bullet]/2])][sub 2][sup +] (M = Ni or Cu), and they possess a single electron holes per pair of porphyrin rings; both form discrete dimers in the solid state. The absence of an obvious covalent bond in these dimers distinguishes them from al previously characterized [open quotes]partially oxidized[close quotes] bis(porphyrin) systems. 21 refs., 4 figs.