K. Oyaizu et al., Molecular structure of a mu-oxo chromium-iron complex: Rare example of a crystallographically characterized mu-oxo heterometallic porphyrin, B CHEM S J, 72(8), 1999, pp. 1781-1784
The crystal structure of a mu-oxo heterometallic porphyrin [(pip)(tpp)(CrOF
eIII)-O-III(tpp)] (pip = piperidine) not only confirmed the proposed oxidat
ion state of chromium and iron atoms, but also revealed a unique coordinati
on environment around chromium(III), which is substantially protruded from
the porphyrin plane.