Metallophthalocyanine using

Oxidation of pollutants catalyzed by metallophthalocyanins 97ACR470. Recent developments in the use of A-phthaloyl-amino acid derivatives in synthesis 98SL457. 

The first catalysts reported for the electroreduction of C02 were metallophthalocyanines (M-Pc).126 In aqueous solutions of tetraalkylammonium salts, current-potential curves at a cobalt phthalocyanine (Co-Pc)-coated graphite electrode showed a reduction current peak whose height was proportional to the C02 concentration and to the square root of the potential sweep rate at a given C02 concentration. On electrolysis, oxalic acid and glycolic acid were detected, but formic acid was not. Mn and Pd phthalocyanines were inactive, while Cu and Fe phthalocyanines were slightly active. At the potentials used for C02 reduction, M-Pc catalysts would be in their dinegative state, and the occupied dz2 orbital of the metal ion in the metallophthalocyanine was suggested to play an important role in the catalytic activity. 

Several metallophthalocyanines have been reported to be active toward the electroreduction of C02 in aqueous electrolyte especially when immobilized on an electrode surface.125-127 CoPc and, to a lesser extent, NiPc appear to be the most active phthalocyanine complexes in this respect. Several techniques have been used for their immobilization.128,129 In a typical experiment, controlled potential electrolysis conducted with such modified electrodes at —1.0 vs. SCE (pH 5) leads to CO as the major reduction product (rj = 60%) besides H2, although another study indicates that HCOO is mainly obtained.129 It has been more recently shown that the reduction selectivity is improved when the CoPc is incorporated in a polyvinyl pyridine membrane (ratio of CO to H2 around 6 at pH 5). This was ascribed to the nature of the membrane which is coordinative and weakly basic. The microenvironment around CoPc provided by partially protonated pyridine species was suggested to be important.130,131 The mechanism of C02 reduction on CoPc is thought to involve the initial formation of a hydride derivative followed by its reduction associated with the insertion of C02.128... 

Interesting results have been obtained using metallophthalocyanines supported on porous carbon gas diffusion electrodes.132-136 In the case of CoPc and NiPc, CO is formed with a current efficiency of almost 100%.135 With Sn, Pb, and In phthalocyanines, mainly HC02H is formed, while Cu and Ti phthalocyanines promote the formation of CH4. The reason why some metal Pc complexes give CO or CH4, while others yield HC02H, has been interpreted in terms of the electron configuration in the metal.137 A rather different type of reaction is the very recent demonstration of the simultaneous reduction of C02 and N02 to give urea (NH2)2CO, which can be achieved with an efficiency up to 40% at similar gas-diffusion electrode devices with a NiPc supported catalyst.138... 

This reaction has been observed for porphyrins, and used to establish relative stabilities.51,53 It is of practical use in the preparation of metal complexes, e.g., metallophthalocyanines by metal exchange with dilithium(I) phthalocyanine.54... 

Photoproduction of Hydrogen from Water Using Metalloporphyrin and Metallophthalocyanine... 

Metallophthalocyanines, (MPc s) possess a very intense absorption at about 680 nm (e> 10s dm3 m jl"1 cm 1) which is blue shifted on complexation with third row transition elements. They can absorb a large fraction of the solar spectrum, but their potential application to hydrogen production is limited by their tendency to aggregate in solution118 (although where the system allows, this aggregation can be prevented by the use of pyridine (5% w/w) or micelles). 

The double-pump flash photolysis technique has been used for two different applications the photogeneration of products different from those obtained with the pump and probe flash photolysis technique anda mapping of the potential surfaces of electronic excited states positioned above the lowest electronic excited state. For example, the flash irradiation of the metallophthalocyanine, M(pc)X (M = Rh(III), A1 (III) and X = C1 or Br) in the presence of Co(bpy)j+ produces the cyclic process described in Equations 6.60-6.62.28... 

Coal Liquid Upgrading Using Metallophthalocyanine Catalysts ... 

HDN with Metallophthalocyanines. The above considerations clearly show that the catalytic site geometry is important in HDN. It is difficult to control, or even to identify, the catalyst site in conventional catalysts such as the commercial Co-Mo-alumina catalyst. On the other hand, homogeneous catalysts with transition metal complexes provide a well-defined catalytic site. Unfortunately, most homogeneous catalysts are not sufficiently stable to be used at the temperatures required for the hydrogenation of hetero compounds. A class of catalysts that are thermally stable are the metallophthalocyanines,... 

Materials. Metallophthalocyanines were purchased from commercial sources and used without further purification. 

Phthalocyanine itself is best prepared3 by self-condensation of phthalimidine, which is available from the reaction of phthalonitrile with ammonia. However, in many cases, direct metalation of the macrocycle cannot be achieved. Instead, metalation by means of dilithium phthalocyanine or a template reaction, whereby the macrocycle is formed around the metal using phthalonitrile (or one of its derivatives), must be employed for the synthesis of metallophthalocyanins. 

Despite their superior photoproperties, metallophthalocyanines have not found use as... 

In the template method the zeolite is allowed to crystallize around the metal complex which is assumed to act as a structure directing agent, i.e. the bottle is built around the ship. This allows for the encapsulation of well-defined complexes without contamination by the fi-ee ligand or uncomplexed metal ions (see above). The method is restricted to metal complexes that are stable under the relatively harsh conditions of temperature and pH involved in hydrothermal synthesis. Balkus and coworkers [14,40,41] used this approach for the encapsulation of metallophthalocyanines in faujasite. However, in order to fit into the faujasite supercages the phthalocyanine ligands are strongly deformed and Jacobs has... 

Bouvet, M. et al.. Detection and titration of ozone using metallophthalocyanine based field effect transistors. Sens. Actuators B., 72, 86, 2001. 

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