Porphyrin-containing complexes

The detection of DNA strands by NIR luminescent lanthanide complexes is possible through the modulation of Yb luminescence in Pd-porphyrin-containing complexes upon nucleic acid binding [48] or by the sensitivity of the intramolecular energy transfer towards the presence of DNA sensing in coumarin-rhodamine-modified ytterbium complexes [95]. 

One-electron oxidation of the vinylidene complex transforms it from an Fe=C axially symmetric Fe(ll) carbene to an Fe(lll) complex where the vinylidene carbon bridges between iron and a pyrrole nitrogen. Cobalt and nickel porphyrin carbene complexes adopt this latter structure, with the carbene fragment formally inserted into the metal-nitrogen bond. The difference between the two types of metalloporphyrin carbene, and the conversion of one type to the other by oxidation in the case of iron, has been considered in a theoretical study. The comparison is especially interesting for the iron(ll) and cobalt(lll) carbene complexes Fe(Por)CR2 and Co(Por)(CR2) which both contain metal centers yet adopt... 

Diazoalkanes are u.seful is precursors to ruthenium and osmium alkylidene porphyrin complexes, and have also been investigated in iron porphyrin chemistry. In an attempt to prepare iron porphyrin carbene complexes containing an oxygen atom on the /(-carbon atom of the carbene, the reaction of the diazoketone PhC(0)C(Ni)CH3 with Fe(TpCIPP) was undertaken. A low spin, diamagnetic carbene complex formulated as Fe(TpCIPP)(=C(CH3)C(0)Ph) was identified by U V-visible and fI NMR spectroscopy and elemental analysis. Addition of CF3CO2H to this rapidly produced the protonated N-alkyl porphyrin, and Bit oxidation in the presence of sodium dithionitc gave the iron(II) N-alkyl porphyrin, both reactions evidence for Fe-to-N migration processes. ... 

The second structural type found for organometallic cobalt porphyrins contains an organic fragment bridged between the cobalt and one pyrrolic nitrogen. Cobalt complexes of N-alkyl- or N-arylporphyrins arc well established (but will not be specifically addressed here). The bridged complexes are derivatives of these where the N-alkyl group also forms a cr-bond to cobalt. They are also related to the axially... 

Monomeric Irn-containing complexes have been isolated for sterically demanding porphyrin-type ligands (por). Wayland et al,472 generated Ir11 tetrakis(2,4,6-trisalkylphenyl)porphyrin by photolysis of the Ir-Me derivative in Cf,Df, according to Reaction Scheme 23. 

Literature reports of NO disproportionation reactions with Fe(II) porphyrins contain many mutually inconsistent observations. Although facile NO disproportionation is promoted by Ru(II) and Os(II) (88) porphyrins to yield N20 and the respective M(Por)(NO)(ONO) complexes, the reactivity appears to be quite different with analogous Fe(II) complexes. Ferrous porphyrins such as Fen(TPP) undergo NO addition in ambient temperature solution to give the relatively stable... 

The same group has synthesized well-defined porphyrin-containing PArEs 27 and 28 [27]. The central metal cation could complex to various solvent ligands. Depending on the electron-donating ability of the solvent ligand, com-plexation of solvent to metal ion changes the electron density on the porphyrin... 

Aluminum porphyrins first came to attention with the discovery that the simple alkyl complex Al(TPP)Et was capable of activating CO2 under atmospheric pressure. Both irradiation with visible light and addition of 1-methylimidazole were required for the reaction, which was proposed to proceed by initial coordination of the base to aluminum. The aluminum porphyrin containing direct product of CO2 insertion was not isolated, but was proposed on the basis of IR data to be (TPP)A10C(0)Et, which was then treated with HCl gas, presumably liberating propanoic acid, subsequently isolated as the butyl or methyl ester after reaction with 1-butanol or diazomethane, respectively [Eq. (5)]. Insertion of CO2 into the Al—C bond of an ethylaluminum phthalocyanine complex has also been reported. ... 

Crude oil consists mainly of a mixture of paraffinic, naphthenic, and aromatic hydrocarbons with small amounts of metals-containing heterocyclic compounds. The most abundant metals found in oils are those contained in porphyrin or porphyrin-like complexes (nickel, copper, iron, and vanadium). These... 

Synthetic porphyrins have been used extensively as model systems for investigating the complex biological functions of natural porphyrin-containing systems. Given the capabilities of porphyrins to bind and release gases and to act as the active center in catalytic reactions in biological systems, porphyrin-... 

Clinical samples often contain complex mixtures of different porphyrins. Porphyrin solubility in organic solvents is inversely proportional to the number of acid side chains. Indoles in the urine may also give a positive result. 

Porphyrin. A complex planar structure containing four substituted pyrroles covalently joined in a ring and frequently containing a central metal atom. For example, heme is a porphyrin with a central iron atom. 

Treibs isolated the first porphyrin coordination complex from a Swiss marl,265 and showed that it (or at least a structurally related derivative) occurred in a wide variety of sedimentary rocks and asphalts. He showed it to contain vanadium and subsequently the involvement of the vanadyl ion was proved.266 Treibs also described a second chelate from the same original source, which he proposed to be an iron complex. Somewhat later it was shown that the complex contained the Ni" ion. It is thus appropriate, and in view of much of the foregoing discussion, to focus attention on the detailed structure of the few fully characterized geoporphyrin complexes recently reported, since their elucidation crowns some five decades of intense activity in this area of coordination geochemistry. 

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