Electron density studies of porphyrins and phthalocyanines. III. The electronic ground state of iron(II) phthalocyanine

摘要

The electron density distribution in Fendash;phthalocyanine is mapped using a set of accurate diffraction data collected at 110 K. Structural results are in agreement with an earlier roomhyphen;temperature determination. Deformation electron density maps show a deficiency of the Fe electron density along the axis perpendicular to the molecular plane and excess along the diagonals of the Fendash;N(pyrrole) directions. Other deformation density features are observed in the bonds of the macrocyclic ligand and in the nitrogen lonehyphen;pair regions. The distribution around the Fe atom indicates the3EgAstate to be the leading contributor to the ground state of FePc. This conclusion is further supported by the results of a multipole refinement in which sphericalhyphen;harmonic electron density deformation functions are fitted to the distribution around each of the atoms. The calculated Mouml;ssbauer shift is in agreement with the spectroscopically observed value.