| Popis: |
The octaethylporphyrin(OEP) complexes of iron(III) chloride, iron(III) acetate, thallium(III) hydroxide, zinc(II), and cobalt(II) and the mesoporphyrin IX dimethyl ester (MPDME) complexes of zinc(II) and iron(III) chloride were reacted with a 20:1 ratio of NO 2 to metalloporphyrin in CH 2 Cl 2 . The +3 metalloporphyrins gave products which had a nitromethyl group in each of the four meso positions of the porphyrin ring and a chloride ion bound to the metal atom. The products of +2 metalloporphyrin reaction had a nitro group bound in each of the meso positions. The spectral and electrochemical properties of some of the products were measured. 36 Cl labelled OEPFeCl was reacted with NO 2 in CH 2 Cl 2 . The product, meso -tetranitromethyl OEPFeCl, had 17% of the original activity which indicates that the chloride ion bound to the iron is exchanged with chloride ions formed in the reaction. The nitromethylation reaction appears to involve initially the displacement of chloride from iron(III) by NO 2 and solvent attack on the bound NO 2 . The meso -nitration of the +2 metalloporphyrin by NO 2 has been proposed to proceed by a π-cation radical mechanism (E.C. Johnson and D. Dolphin, Tetrahedron Letters 2197 (1976). |
