Zinc-metalloporphyrin

Functionalization can be used to alter the redox properties of the zinc metalloporphyrin the zinc heptanitroporphyrin shows facile reduction to the air-stable 7r-anion radical.768 Modification of the zinc porphyrin at the, 8 position with chlorine or bromine to induce saddling of the... 

The inhibition of lipid peroxidation by metalloporphyrins apparently depends on metal ions because only compounds with transition metals were efficient inhibitors. Therefore, the most probable mechanism of inhibitory effects of metalloporphyrins should be their disuniting activity. Manganese metalloporphyrins seem to be more effective inhibitors than Trolox (/5o = 204 pmol I 1) and rutin (/50 112 pmol I 1), and practically equal to SOD (/50= 15 pmol I 1). The mechanism of inhibitory activity of manganese and zinc metalloporphyrins might be compared with that of copper- and iron-flavonoid complexes [167,168], which exhibited enhanced antiradical properties due to additional superoxide-dismuting activity. 

Beer, P. D., Cormode, D. P, Davis, J. J., Zinc metalloporphyrin-functionalised nanoparticle anion sensors. Chem. Commun. 2004,414-415. 

ANION RECOGNITION AND SENSING BY AMIDOFERROCENE SELF-ASSEMBLED MONOLAYERS ON GOLD ELECTRODES AND ZINC METALLOPORPHYRIN-FUNCTIONALISED GOLD NANOPARTICLES... 

Metal nanoparticles have extraordinary size-dependent optical properties, not present in the bulk metal and have, consequently, been the subject of intense research during the past decade or so.27 Attention has recently focused on functionalising colloidal nanoparticles with molecular recognition components for potential sensing applications.28,29,30 We have prepared a new amido-disulfide functionalised zinc metalloporphyrin (8) which was self-assembled on to gold nanoparticles to produce a novel anion-selective optical sensing system (9) (Scheme 3).4... 

Several reports concerning zinc metalloporphyrins have appeared. Spaulding et al.216 have determined the crystal structure of the radical perchloratotetraphenyl-porphinatozinc(n). The zinc is five-co-ordinate, with a very strongly bound perchlorate forming the apex of a pyramid, the square base of which is formed by the four nitrogens of the porphyrin ring. 

Beer. P.D. Drew. M.G.B. Jagessar. R. Selective anion recognition by novel 5,10,15,20-tetrakis(o-ferrocenylcar-bonylaminophenyl-substituted) zinc metalloporphyrin receptors. J. Chem. Soc. Dalton Trans. 1997, 5, 881. 

The coordination catalysts for these reactions are diverse. They can be compounds of alkaline earth metals, like calcium amide, or calcium amide-alkoxide. They can also be Ziegler-Natta-type catalysts. These can be alkoxides of aluminum, magnesium, or zinc combined with ferric chloride. Others are reaction products of dialkylzinc with water or alcohol. They can also be bimetallic //-oxoalkoxides, such as [(RO)2A102]Zn. Other catalysts are aluminum or zinc metalloporphyrin derivatives (see Fig. 4.1). 

Another class of porphyrins, substituted by 3,5-di-i-butylphenyl groups at the a and Y meso positions, has recently been studied using the fs fluorescence up-conversion technique [128], Following excitation into the Sj state, the zinc metalloporphyrin species undergoes an Sj-Sj internal conversion with a time constant of 150 fs before intramolecular vibrational relaxation takes place in the Q state with a time constant of 600 fs. In the case of the free-base porphyrin, the system relaxes from the B state to the Qy state within 40 fs, followed by internal conversion between the Qy and states in 90 fs. Subsequently, IVR occurs in the state in 1.5 ps before the porphyrin returns to its ground state in 12 ns. 

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