Design,synthesis And Characterization Of Substituted Metal Porphyrin-like Enzyme Mimics Catalysts

Porphyrin-like compounds (including metal phthalocyanines) are compounds with special structure and unique characters. They are widely used in many fields, especially as important mimic enzyme catalysts which catalyze the selective oxidation functionallization of saturated hydrocarbons, aromatic hydrocarbons and its side chain with 02. Because different central metal ions, substituents at phenyl rings of porphyrin and axial ligands have significant effects on their atJ tic activity, so that we can improve their catalytic activity by adjusting central metal ions, introducing various substituents on phenyl rings and axis of porphyrin-like compounds. Basis on the described ideas, 9 series and altogether 40 porphyrin-like compounds with different structures or center metal ions were designed, and two series and altogether 12 porphyrin-like compounds were synthesized, and the structures and catalytic activities of these catalysts were characterized. Firstly, four 2,9,16,23-tetracarboxylicphthalocyanines of Co, Fe, Cu, Zn were synthesized from trimellitic anhydride, urea, and metal salts. The structures of these compounds were characterized and confirmed by JR. UV-Vis and MS. Secondly, eight tetra-(o/p-chlorophenyl) porphyrins of Co, Fe, Cu and Zn were synthesized from oip -chloro-benzaldehydes, pyrrole and metal salts, in which five are new compounds which were not reported by literatures so far. The structures of these compounds were determined by JR. UV-Vis and MS. The structures of 5 new compounds were further confirmed by High Resolution Mass Spectrum. Catalytic activities of these compounds were investigated by means of dioxygen liquid-phase oxidation of o -nitrotoluene to o-nitrobenzoic acid at the mild conditions of4OXD and 3MPa. It was found that o-nitrobenzoic acid could not be obtained from oxidation of o-nitrotoluene when no catalyst. The yield of o-nitrobenzoic acid all can reach more than 40% by using anyone of 12 catalysts synthesized. The results showed that all 12 catalysts synthesized had significant catalytic activity for above reaction. And, when the center metal ions are identical, the activity order of 12 catalysts is: tetra-(o-chlorophenyl) metal porphyrins> tetra-(o-chlorophenyl) metal porphyrins > metal phthalocyanine tetracarboxylic acids; When the ligands are the same and central metal ions are different, the catalytic activity sequence of 4 metal complexes is Co > Zn> Cu> Fe; In addition, the catalytic activity of tetra-(o-chlorophenyl) cobalt porphyrin was the best among 12 metal porphyrin-like compounds, and the yield in 66.8% of o-nitrobenzoic acid was obtained. The above-listed results showed that kinds of the center mental ions, properties of parent rings and the positions of substituents all had some effect on catalytic oxidation performance of metal porphyrin-like compounds...