Inorganic Chemistry, Vol.36, No.16, 3568-3572, 1997
Highly Stabilized Low-Spin Iron(III) and Cobalt(III) Complexes of a Tridentate bis-Amide Ligand 2,6-bis(N-Phenylcarbamoyl)Pyridine - Novel Nonmacrocyclic Tetraamido-N Coordination and 2 Unusually Short Metal-Pyridine Bonds
Two novel low-spin complexes, [Et4N][FeL2.15H(2)O (1) and [Et4N[CoL2].2H2O (2) (L is a deprotonated bis-amide ligand), have been synthesized and characterized. Four relatively longer equatorial M-N-amide bonds and two significantly shorter axial M-N-py bonds are the noteworthy features of their X-ray structures. EPR and (34-300 K) magnetic studies of 1 confirm its low-spin character. Cyclic voltammetric studies reveal a highly stabilized M(III) state. For I a linear correlation between the Fe(III)-Fe(II) reduction potentials and the reciprocal of solvent dielectric constants is obtained.
Keywords:SYNTHETIC ANALOG APPROACH;REDOX PROPERTIES;CRYSTAL-STRUCTURE;BLEOMYCIN;N-(2-HYDROXYPHENYL)SALICYLAMIDE;METALLOBLEOMYCINS;ELECTROCHEMISTRY;DECOMPOSITION;HYDROXYLATION;HOMOLOGS