PARAMAGNETIC ANISOTROPY, AVERAGE MAGNETIC-SUSCEPTIBILITY, AND ELECTRONIC-STRUCTURE OF INTERMEDIATE-SPIN S = 1 (5,10,15,20-TETRAPHENYLPORPHYRIN)IRON(II)

Measurements of average magnetic susceptibility and magnetic anisotropy on the single crystals of FeTPP in the 4-300 K temperature range are reported. These results together with the other existing evidence establish an S = 1 spin state for the iron(II) ion in FeTPP. It is shown that the experimental principal susceptibilities cannot be explained over the entire temperature region by a spin Hamiltonian formalism for the 5 = 1 ground state. A detailed ligand field calculation is presented which gives a satisfactory explanation of the magnetic data. The ligand field calculation indicates a dz orbital lying lowest with 3A2as the ground state followed by 3E and 3B, in ascending order of energy. The best fit to the data is obtained only in the region where three states come close together. © 1979, American Chemical Society. All rights reserved.