Structure and magnetic properties of (mu-oxo)bis[meso-tetrakis(p-tolyl-porphyrinato)iron(III)] and (mu-oxo)bis[N,N '-ethylenebis(2-acetylphenoliminato)iron(III)]

Synthesis, structure and magnetic properties of (mu-oxo)bis[meso-tetrakis(p -tolyl-porphyrinato)iron(III)] (1), [(TTP)Fe](2)O, and (mu-oxo)bis[N,N'-eth ylenebis(2-acetylphenoliminato)iron(III)] (2), [(aceten)Fe](2)O, are report ed. X-ray crystallographic studies reveal the structure in which two iron(I II) atoms are bridged by the oxo groups in compounds 1 and 2. The bridging angle of 178.2(3)degrees for 1 is larger than that of 156.5(3)degrees for 2 . The average Fe-O(mu) bond lengths are 1.74(3) and 1.7723(17) Angstrom for 1 and 2, respectively. The average displacements of the iron(III) atoms fr om the mean N-4 plane in 1 and the N2O2 coordinated plane in 2 are 0.53 and 0.59 Angstrom, respectively. The average N-Fe(1)-Fe(2)-N' twist dihedral a ngle is 24.70 degrees for 1. Antiferromagnetic coupling shows an increase a s the bridging angle Fe-O-Fe increases and the average Fe-O(mu) bond length decreases: J = - 142 cm(-1) for 1 and - 104 cm(-1) for 2. (C) 1999 Elsevie r Science S.A. All rights reserved.