Tetra-pyridyl-porphyrin

Amino-l,2,4-benzotriazine 1,2-dioxide Thin layer chromatography Thymidine-5 -phosphate iV,iV,iV, iV -Telramclhylphcnylcncdiamine Tetranitromethane 3,5,4 -Trihydroxy-frans-stilbene 2-Amino-2-hydroxy-l, 3-propanediol Time-resolved light-scattering p-[meso-5-5,10,15,20-Tetra(pyridyl)porphyrin]tetra kis[ (ns-(bipyridine) chloride ruthenium(II)]... 

TRP = g [meso-5,10,15,20-tetra(pyridyl) porphyrin]tetrakis[bis(bipyridine)chloride ruthenium(ll)]... 

Through coor nation motif, a tetra-pyrazinyl porphyrin-based assembly with four dimeric [meso-tetrakis(2-carboxy-4-nonylphenyl)porphyrinato]-zinc(II) as the antenna moiety was constructed by Kuroda et al. [113]. The efficiency of energy transfer from the zinc porphyrin-pyrazine complex to the free base porphyrin has been determined to be 82%. Also for this system, the observed efficiency of energy transfer is not so high compared with those reported for covalently finked multi-porphyrin systems [114]. Himter s group has designed a pentameric porphyrin array, wtiich was built up by the complementary coordination of a tetra-pyridyl porphyrin and two zinc-porphyrin dimers [115]. Steady-state and time-resolved fluorescence spectroscopic studies revealed that the energy transfer efficiency of this array is around 70%. 

The adsorption of transition metal complexes by minerals is often followed by reactions which change the coordination environment around the metal ion. Thus in the adsorption of hexaamminechromium(III) and tris(ethylenediamine) chromium(III) by chlorite, illite and kaolinite, XPS showed that hydrolysis reactions occurred, leading to the formation of aqua complexes (67). In a similar manner, dehydration of hexaaraminecobalt(III) and chloropentaamminecobalt(III) adsorbed on montmorillonite led to the formation of cobalt(II) hydroxide and ammonium ions (68), the reaction being conveniently followed by the IR absorbance of the ammonium ions. Demetallation of complexes can also occur, as in the case of dehydration of tin tetra(4-pyridyl) porphyrin adsorbed on Na hectorite (69). The reaction, which was observed using UV-visible and luminescence spectroscopy, was reversible indicating that the Sn(IV) cation and porphyrin anion remained close to one another after destruction of the complex. 

The water-soluble Fe porphyrin, 3Na+ [Fe(III)(TPPS)] -12H20 [H2TPPS4- = tetra-anionic form of meso-tetrakis(7r-sulfonatophenyl)porphine], has recently been shown to be an effective catalyst for the electroreduction of nitrite to ammonia [419]. The Fe meso-tetrakis(A -methyl-4-pyridyl) porphyrin and/or the Fe meso-tetrakis (jr -sulfophenyl) porphyrin complex shows a catalytic activity for the reduction of dioxygen in aqueous solutions, leading to hydrogen peroxide [420]. 

N,N -ethylenebis(salicylideneiminato) ion meso-tetra(2,4,6 -trimethyl- 3,5 -disulfonato)porphin 5,10,15,20 -tetrakis(N-methyl- 4 -pyridyl)porphyrin... 

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. 

Cationic metalla-assemblies have been prepared using the same dinuclear arene ruthenium clips and 5,15-bis(4-pyridyl)-10,20-diphenylporphyrin (bpp) or 5,10, 15-tris(4-pyridyl)-20-phenylporphyrin (tppp) instead of 5,10,15,20-tetra(4-pyridyl) porphyrin (tpp) (Fig. 15). The in vitro study showed that, despite having less ruthenium atoms per metalla-assemblies and a reduced overall charge as compared to the octanuclear arene ruthenium metalla-cubes, the cytotoxicity of these tetra-and hexanuclear metalla-assemblies was similar to those observed for the octanuclear metalla-cubes [55]. 

II 000 cm-1). Nevertheless, the photophysics of lanthanide porphyrinates is attractive because it could be of great help in medicine. For instance, hematoporphyrin derivatives are known to accumulate in malignant tumours and are used in medical diagnosis and photodynamic therapy of cancer. It is noteworthy that the Yb(III) complex with meso-tetra(3-pyridyl)porphyrin displays a substantial quantum yield (1.4%) when inserted into micelles formed by the non-ionic surfactant Triton X-100, a medium that can be considered as a model for biological tissues. 

Tetra(4-pyridyl) porphyrin (TPyP) metalloligands also were explored as potential MOF constituents. It is of more than passing interest that TPyPs are often capable of self-association via bonding of the pyridyl nitrogens to the coordina-tively unsaturated central metal of another porphyrin molecule. Several research groups have made an active study of such stmctures (111-117). However, because these coordination polymers tend to be formed from a single molecular component, rather than having the metalloporphyrin bound to a secondary metal center or SBU, they will be omitted from further discussion here. 

Another series of model compounds is based on cobalt weyo-tetra(4-pyridyl) porphyrins with four [Ru(NH3)5] " or [Ru(edta)] groups (electron donors) coordinated to the peripheral V-pyridyl atoms (117-119). Such species exhibited faster ET kinetics because the four ruthenium complexes can act as reservoirs and CT relays for electron exchange with the electrode surface (118). However, it was shown that the peripheral complexes do not change the two electron reduction mechanism (353). 

Metal clusters Mallouk and co-workers reported on procedures to generate small particles of Pt inside zeolite L channels, which they used as catalysts for hydrogen formation [154]. The electron transport chain was composed of EDTA as sacrificial electron donor, zinc tetra(A-methyl-4-pyridyl)porphyrin (ZnTMPy +) as sensitizer and methylviologen (MV +) as electron acceptor. The zeolite host used was zeolite L, which has a one-dimensional tunnel-like structure (Figure le). Small Pt clusters were formed inside the zeolite and then loaded with by ion exchange. Since... 

The direct labelling of TOPO capped semiconductor CdSe or CdSe/ZnS QDs with tetra-pyridyl substituted porphyrin (Fig. 1). Here P is based on the coordination of the pyridyl N lone pair with Zn or Cd atoms on the surface of QD. 

A further interesting application of self-assembly is the synthesis of a chromo-phore containing five porphyrin units [62]. Acting as a model for light-collecting porphyrin adducts, it is important for the understanding of energy and electron transfer in natural photosynthetic active centers. If me5 o-tetra(4-pyridyl)porphyrin... 

The anthraquinone derivative (2) represents the first example from 1997, with numerous others following in rapid succession, including the dibenzo-phenanthroline derivatives and tri-substituted acridines (3), which were reported to inhibit telomerase action in tumour cell lines with IC50 values of up to 28 and 60 nM, respectively. The tri-substituted acridines (3) were developed from the simple acridine (4) on the basis of structure-based design principles to maximise the quadruplex binding affinity. Thus, inhibition of telomerase by these compounds appears to be correlated to selective stabilisation of the human DNA quadruplex structure. Tetra-(A-methyl-4-pyridyl)-porphyrins... 

Persaud, L., Bard, A. J., Campion, A., Fox, M. A., Mallouk, T. E., Webber, S. E., White, J. M. (1987). Photochemical hydrogen evolution via singlet-state electron-transfer quenching of zinc tetra(N-methyl-4-pyridyl)porphyrin cations in a zeolite L based system, J. Am. Chem. Soc., 109 7309. 

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