Zinc tetrakis porphyrin

Utilizing FT-EPR teclmiques, van Willigen and co-workers have studied the photoinduced electron transfer from zinc tetrakis(4-sulfonatophenyl)porphyrin (ZnTPPS) to duroquinone (DQ) to fonn ZnTPPS and DQ in different micellar solutions [34, 63]. Spin-correlated radical pairs [ZnTPPS. . . DQ ] are fomied initially, and the SCRP lifetime depends upon the solution enviromnent. The ZnTPPS is not observed due to its short T2 relaxation time, but the spectra of DQ allow for the detemiination of the location and stability of reactant and product species in the various micellar solutions. While DQ is always located within the micelle, tire... 

When a photosynthetic organism is omitted, the addition of a photosensitizer is necessary. The methods use light energy to promote the transfer of an electron from a photosensitizer to NAD(P) via an electron transport reagent [6g]. Recently, carbon dioxide cvas reduced to formic acid with FDH from Saccharomyces cerevisiae in the presence of methylviologen (MV ) as a mediator, zinc tetrakis(4-methylpyridyl) porphyrin (ZnTMPyP) as a photosensitizer, and triethanolamine (TEOA) as a hydrogen source (Figure 8.8) [6h]. 

DCE interface in the presence of TPBCl [43,82]. The accumulation of products of the redox reactions were followed by spectrophotometry in situ, and quantitative relationships were obtained between the accumulation of products and the charge transfer across the interface. These results confirmed the higher stability of this anion in comparison to TPB . It was also reported that the redox potential of TPBCP is 0.51V more positive than (see Fig. 3). However, the redox stability of the chlorinated derivative of tetra-phenylborate is not sufficient in the presence of highly reactive species such as photoex-cited water-soluble porphyrins. Fermin et al. have shown that TPBCP can be oxidized by adsorbed zinc tetrakis-(carboxyphenyl)porphyrin at the water-DCE interface under illumination [50]. Under these conditions, the fully fluorinated derivative TPFB has proved to be extremely stable and consequently ideal for photoinduced ET studies [49,83]. Another anion which exhibits high redox stability is PFg- however, its solubility in the water phase restricts the positive end of the ideally polarizable window to < —0.2V [85]. 

More recently, a series of papers based on photocurrent responses involving water soluble porphyrin species has allowed to address the various aspects involved in the mechanism of Fig. 11 [50,73,83]. Photocurrent transients at the water-DCE interface in the presence of zinc tetrakis(carboxyphenyl) porphyrin (ZnTPPC" ) and Fc under monochromatic light are shown in Fig. 15 at various Galvani potential differences [50]. The... 

The decay of zinc tetrakis(A -methylpyridinium-4-yl(porphyrin 7r-radical cations in the presence of poly(styrenesulfonate) and IrIV oxides or [Ir(OI I )r,]2 has been studied at high pH.46 The hexahydroxide species was found to be very reactive. 

NADH Nicotineamide adenine dinucleotide reduced form. EDTA Ethylenediamine tetraacetic acid. RSH Mercaptoethanol. ZnTPP Zinc tetraphenylporphyrin. ZnTMPyP Zinc tetrakis(4-methylpyridyl)porphyrin. ZnTPPS Zinc tetraphenylporphyrin tetrasulfomate. 

Dabestani, R. Bard, A. J. Campion, A. Fox, M. A. Mallouk, T. E. Webber, S. E. White, J. M. Sensitization of titanium dioxide and strontium titanate electrodes by ruthenium(II) tris(2,2 -bipyridine-4,4 -dicarboxylic acid) and zinc tetrakis(4-carboxy-phenyl)porphyrin An evaluation of sensitization efficiency for component photo-electrodes in a multipanel device, J. Phys. Chem. 1988, 92, 1872. 

S. Mosseri, J.C. Mialocq, B. Perly, and P. Hambright, Porphyrins-Cyclodextrin. 1. Photooxidation of Zinc Tetrakis(4-sulfonatophenyl)porphyrin in Cyclodextrin Cavities The Characterization of ZnTSPP Dication. Photolysis, Radiolysis, and NMR Studies, J. Phys. Chem., 95 (1991) 21%. 

First, it was shown that the presence of an electron donor or an electron acceptor in the organic phase resulted in photocurrents associated with a reductive and oxidative quenching of the water-soluble zinc tetrakis(carboxyphenyl)porphyrin (ZnTPPC), respectively, as shown in Figure 1.25 [227]. 

Lebold TP, YeowEK, Steer RP (2004) Fluorescence quenching of the SI andS2 states of zinc meso-tetrakis(4-sulfonatophenyl)porphyrin by halide ions. Photochem Photobiol Sci 3 ... 

Recently, the high inhibitory efficiency of metalloporphyrins has been shown in lipid peroxidation of rat brain homogenates [346]. It was found that manganese and cobalt porphyrins were very effective inhibitors of lipid peroxidation while iron and especially zinc porphyrins had very weak inhibitory activity, if any. For example, /50 values were equal to 21, 29, 212, 946 pmol 1 1 for CoTBAP, MnTBAP, FeTBAP, and ZnTBAP, respectively, where TBAP is 5,10,15,20-tetrakis [4-carboxyphenyl]porphyrin similar values were obtained for other porphyrin derivatives. 

Zinc me.w-tetrakis (p-carboxyphenyl)porphyrin (ZnTPPC), a neutral molecule, can be readily intercalated into the Li-Al LDH-myristate interlayers by replacing the myristate ions [101b], However, the uptake of the ZnTPPC into this material was minimal. The diffraction pattern showed that, as is the case with other porphyrins, ZnTPPC intercalates with its plane perpendicular to the metal hydroxide layer. The emission spectrum (excitation at 407 nm) of the intercalated guest is similar to that of nonaggregated ZnTPPC in solution (Fig. 53), suggesting that ZnTPPC is solubilized in the LDH in a dispersed form and not as an aggre-... 

Ng et al. first reported the axial ligation of zinc(II) l,8,15,22-tetrakis(3-pentyloxy) phthalocyanine (1) with meso-pyridyl porphyrins 2 and 3 in chloroform, which form the corresponding edge-to-face dyad and pentad, respectively [25], As shown by UV-Vis spectroscopy, the ground-state tt-tt interactions between the perpendicularly disposed macrocycles in these arrays are insignificant. Upon mixing of phthalocyanine 1, zinc(II) meso-tetra(/Molyl)porphyrin, and 4,4/-bipyridine in chloroform, the formation of a face-to-face hetero-dyad was also inferred by fluorescence quenching experiments. 

HGURE 8.1. Formal potentials of redox species in W, NB and DCE versus NHE. Abbreviations ZnTMPyP = zinc tetra-7V-methyl-4-pyridium porphyrin, DcMFc = decamethylfetrocene, TCNQ = 7,7,8,8-tetracyanoquinodimethane, DiMFc = dimethylferrocene, Fc = ferrocene, RuTPP(py)2 = bisfpyridine) meso-tetraphenylporphyrinato ruthenium(II), SnPc2 = tin(IV) diphthalocyanine, LuPc2 = lutetium(in) di]dithalo-cyanine, DiFcET = diferrocenylethane, TAA = tris(4-methoxyphenyl)amine, TPB = tetraphenylborate, TBrPA = tris(4-bromophenyl)amine, TCIPB = tetrakis(4-chlorophenyl)borate. The data is from Ref. [26], except where otherwise noted Ref. [6], Ref. [29], Ref. [30], Ref. [31], Ref. [32]. Reprinted from Ref. [28], with permission from the Polarographic Society of Japan. 

---