96760-83-7Relevant academic research and scientific papers
Studies of the chemical oxidation of iron(II) complexes of N-methylporphyrins to form the corresponding iron(III) complexes
Balch, Alan L.,La Mar, Gerd N.,Latos-Grazynski, Lechoslaw,Renner, Mark W.
, p. 2432 - 2436 (2008/10/08)
Oxidation of iron(II) N-methylporphyrin halide complexes with chlorine, bromine, or iodine in chloroform solution at -50°C produces the corresponding iron(III) N-methylporphyrin halide cations. The oxidations may be reversed by treating the product solutions with zinc. The iron(III) complexes have been characterized by electronic, 1H and 2H NMR, and ESR spectroscopy. The NMR results indicate that the Cs symmetry of the iron(II) parent complexes is retained upon oxidation. Characteristic 1H NMR shifts for these high-spin (S = 5/2) species include the very broad N-methyl resonance at ca. 270 ppm (observed only by 2H NMR), three pyrrole resonances in the 130-75 ppm region and one at ca. 2 ppm, pyrrole methylene resonances in the range 80-20 ppm and meso resonances at ca. -70 ppm. The electronic structure of these iron(III) complexes are similar to those of symmetrical high-spin, five-coordinate iron(III) porphyrins except for the local environment of the methylated pyrrole, which suffers from sharply reduced σ-spin transfer as a consequence of the longer Fe-N distance to that ring. On warming, these iron(III) complexes decompose by demetalation (for chloride complexes) or demethylation (for bromide complexes).
