Electron density studies of porphyrins and phthalocyanines. IV. Electron density distribution in crystals of (meso-tetraphenylporphinato) iron(II)

The electron density distribution in crystals of (meso‐tetraphenylporphinato)iron(II) has been analyzed using accurate x‐ray diffraction data collected at 120 K. The structural results are in agreement with those of the room temperature study. Theoretical calculations predict several different ground states for the complex and in particular support the 3A2g and the 3EgA states. The experimental electron density distribution shows large peaks above and below the iron atom which would not be present for a 3EgA ground state. Comparison with Mossbauer quadrupole splittings and the result of the aspherical atom refinement indicate that the axial peaks may be systematically too high in this acentric crystal structure. Nevertheless, it is concluded that their presence indicates a relatively small contribution of the 3EgA state to the ground state of the complex. This implies that the ground state of FeTPP is different from that of iron(II)phthalocyanine in the crystal. A significant population of electrons is fo...

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