Heterogeneous metal-insertion: a novel reaction with porphyrins

Abstract

MEHDI, and ALFIO CORSINI. Can. J. Chem. 56, 1084 (1978). Metal complexes of water-soluble and other porphyrins have been prepared by a heterogeneous reaction with the metal reactant present in an insoluble form. The oxidation state of the metal is important in the reactions. Metal reactants in the lower oxidation states (0, I, 11) react with porphyrins but those in the higher oxidation states (111, IV) do not. Metalloporphyrins of high purity may be conveniently prepared by this method.OTTO HERRMANN, S. HUSAIN MEHDI et ALFIO CORSINI. Can. J. Chem. 56, 1084 (1978). On a prtpart, par une rtaction htttrogtne avec le mttal reactif present sous une forrne insoluble, des complexes mttalliques de porphyrines dont quelques uns sont soluble~ dans I'eau. L'ttat d'oxydation du mttal est important dans les reactions. Les mttaux reactifs dans des ttats d'oxydation peu eleves (0, I, 11) reagissent avec les porphyrines alors que ceux qui existent dans des ttats d'excitation plus elevts (111, IV) ne reagissent pas. On peut facilement prtpart des mttalloporphyrines de grande purett par cette mtthode.[Traduit par le journal] Introduction The biological importance of certain metalloporphyrins (1) and the variety of interesting and useful properties that they exhibit (2, 3) make metalloporphyrins a widely studied class of compounds. To date, complexes of porphyrins with over fifty metals and semi-metals have been prepared (3). The methods for preparing metalloporphyrins depend upon the nature of the metal to be inserted and, to a lesser extent, upon the type of porphyrin to be used. In general, however, these preparative procedures involve refluxing the porphyrin with a suitable soluble metal salt or metal complex in an appropriate solvent (4a, b, 5). We wish to report on a novel heterogeneous reaction for the formation of metalloporphyrins in which the metal to be inserted is present in an insoluble form rather than in solution with the porphyrin.The heterogeneous metal insertion reaction can be carried out using metal oxides, free metals, metal sulphides, and other insoluble metal salts (e.g., Cu2C12) in water or in non-aqueous solvents. The method has been used successfully to prepare metal complexes of meso-tetraCp-sulphophenyl) porphine (TPPS,), hematoporphyrin (HP), protoporphyrin IX dimethyl ester (PPDME), octaethylporphine (OEP), and meso-tetraphenylporphine (TPP). This type of metalloporphyrin formation reaction has the immediate advantage over the more conventional methods in that the excess metal reactant can be removed from the product by simple filtration of the solid phase rather than by the tedious methods, often in combination, of extraction, precipitation, dialysis, and chromatography.

Synthetic and Mechanistic Aspects of a New Method for Ruthenium-Metalation of Porphyrins and Schiff-Bases

“…Under certain conditions, particularly using temperatures just below that of refluxing DMF, Fe-porphyrins, characterized by MS and UV-vis, were the major product; the needles became visibly corroded, consistent with a reported metalation using elemental Fe. 54 Thus, such needles were replaced with long glass pipettes.…”

Sulfonated naphthyl porphyrins as agents against HIV-1

“…Copper insertion was performed by the copper oxide method [30]. The porphyrin (30 mg) was added to refluxing water which contained 500 mg of copper oxide.…”

“…Iron insertion was achieved by adding the porphyrin (30 mg) to refluxing water, which contained 500 mg of powdered iron [30]. The reaction mixture was refluxed for 6 h. The completion of the reaction was indicated by UV/visible (UV/vis) spectroscopy (four Q-bands of free-base porphyrin reduced to two bands of metalloporphyrin).…”

Modified silicas covalently bounded to 5,10,15,20-tetrakis(2-hydroxy-5-nitrophenyl)porphyrinato iron(III): synthesis, spectroscopic and EPR characterization. Catalytic studies

“…20 At the end of the reaction, the iron porphyrin solution was isolated from the remaining Fe 0 by filtration. The product gave rise to one spot by TLC on silica when DMF was used as eluent (R f = 1).…”