Platinum phthalocyanine preparation

Platinum phthalocyanine (PcPt) is prepared by the reaction of phthalonitrile286,288 or isoindolinediimine114,117,288 with platinum(ll) chloride in a solvent such as 2-(dimethyl-amino)ethanol under the catalytic influence of l,8-diazabicyclo[5.4.0Jundec-7-ene. Another possibility is the fusion of phthalonitrile and pialinum(II) chloride58,156,157 or dipotassium tet-rachloroplatinate(II) (K2PtCl4) in the presence of urea, ammonium molybdate(Vl) and sodium sulfate.289... 

Platinum phthalocyanine may be prepared from platinous chloride and phthalonitrile (10). The reaction of phthalonitrile with platinum metal gives only the metal-free derivative. Both these reactions are in contrast... 

The polymer support route is based on the fixation of a phthalonitrile (A) on a polymer, while a different phthalonitrile (B) is added forming a l 3-product, which can be isolated by removing it from the polymer. Unsymmetrically octalkoxy-substituted nickel palladium and platinum phthalocyanines have been prepared recently starting from differently disubstituted phthalonitriles [91]. 

In an interesting study, phthalocyanine complexes containing four anthraquinone nuclei (5.34) were synthesised and evaluated as potential vat dyes and pigments [18]. Anthraquinone-1,2-dicarbonitrile or the corresponding dicarboxylic anhydride was reacted with a transition-metal salt, namely vanadium, chromium, iron, cobalt, nickel, copper, tin, platinum or lead (Scheme 5.6). Substituted analogues were also prepared from amino, chloro or nitro derivatives of anthraquinone-l,2-dicarboxylic anhydride. 

To prepare the standardized dispersion electrode, a mixture of 100 mg soot, 100 g 97% sulfuric acid and 100 mg pigment was stirred direct into the dilute sulfuric acid of the measuring vessel, so that the concentration of sulfuric acid in the electrolyte after stirring in was about 4.5 N. The current collector electrode was a gold-platinum mesh (90/10) of about 4.5 cm2 area. The current/voltage characteristics shown in Fig. 12 make it possible to compare CoTAA with various phthalocyanines. 

Protactinium-233 and neptunium-239 diphthalocyanines are prepared from the corresponding thorium-232 and uranium-238 diphthalocyanines by element transformation [6]. The existence of Pa and Np di-Pcs is proven by repeated sublimation of the irradiated parent compounds using platinum gauze to retain the impurities. Neptunium di-Pc is also synthesized on the tracer scale from irradiated uranium metal, using the normal synthetic method for uranium di-Pc (Example 29) [6], Other actinide phthalocyanines are reported [107-114], Their structures, as well as those of 200 metal phthalocyanines and their derivatives, are classified in an excellent recent review [115]. More recent experimental data on actinide phthalocyanines are absent in the available literature. 

Mg, Be, Ag, Fe(II), Sb(III), Mn(II), Sn(II), alkali metals, alkaline earth metals, rare earths, Cd, Hg, and Pb 19, 21, 54, 119, 226). The rate of demetallation varies considerably 19) (see Section VI,B). The phthalo-cyanines of Cu, Zn, Co(II), Ni, Pt, Pd, VO, Al, Ga, and In resist demetallation in concentrated sulfuric acid at room temperature 10, 21, 56, 57). Phthalocyanine may also be prepared by the condensation of phthalonitrile or 1,3-diiminoisoindoline in hydrogen-donor solvents 10, 81, 86, 346), and by the catalytic condensation of phthalonitrile in the dry with platinum metal 10). Processes involving intermediates such as phthalic acid and urea have also been developed 380). 

Prepared from magnesium or magnesium oxide and o-cyanobenzamide (40), magnesium phthalocyanine has been the subject of much study since it is a synthetic analog of chlorophyll. Perhaps understandably, much of this work has been connected with photosynthesis, luminescence, fluorescence, etc. (see Section V,B). The molecular weight of magnesium phthalocyanine has been measured ebullioscopically in naphthalene (228). Because of the very low solubility of the substance, a very accurate platinum thermometer was employed. Nevertheless the successful measurement represents quite an achievement. 

One can also mention the case of composites-based conducting polymers electrodeposited and characterized on anodes of platinum- or carbon black- filled polypropylene from a stirred electrolyte with dispersed copper phthalocyanine. The electrolytic solution contained, besides the solvent (water or acetonitrile), the monomer (pyrrole or thiophene) and a supporting electrolyte. Patterned thin films were obtained from phthalocyanine derivatives, as reported in the case of (2,3,9,10,16,17,23,24-oktakis((2-benzyloxy)ethoxy)phthalocyaninato) copper . Such films were prepared by means of capillary flow of chloroform solutions into micrometer-dimension hydrophobic/hydrophilic channels initially created by a combination of microcontact printing of octadecylmercaptan (Cig-SH) layers on gold electrodes. These latter gave birth to a hydrophobic channel bottom while oxidative electropolymerization of w-aminophenol (at pH 4) led to hydrophilic channel walls. 

The redox electrochemistry of a Fe /Fe couple is easily accomplished on a phthalocyanine-coated electrode with peak separations comparable to that of platinum [141,142,163,164]. Phthalocyanine-coated electrodes are found to be efficient electrocatalysts to catalys catechol, p-benzoquinone and oxalic acid oxidations [120,150]. The electrochemical activity of these electrodes may be due to the high voltage, surface area, high electronic conductivity and redox behaviour of phthalocyanine, vanadium phthalocyanine and other phthalocyanines have been prepared by vapour deposition and show photoelectrochemical responses when dipped in aqueous electrolytes [244-249]. Polymeric phthalocyanines of Co and Fe are coated on active carbon and are shown to give catalytic properties for dioxygen reduction and thiol oxidations. Dioxygen chemisorption and ammonia absorption of metallo... 

Better stabilities were achieved investigating heat-treated catalysts (section Molecular Centers in Carbonized Materials ). Nevertheless, in most of the cases, even after the heat treatment, considerable decreases of performance were already observed after a few hours of operation time [69, 159, 168, 184, 188, 213-216]. For catalysts prepared by a heat treatment of either iron porphyrin or iron phthalocyanine, it was shown that they are tolerant toward CO [217, 218]. Therefore, we assume that in general, CO-poisraiing can be mled out as degradation mechanism for carbonized materials. Possible degradation mechanisms could be addressed to (1) a corrosion of carbon as known from platinum catalysts, (2) an inactivation by leaching of active sites, or (3) a deactivation of active species (e.g., by blocking of the centers by intermediates or the final products) [71, 98, 99, 102, 190, 191, 210, 211, 219, 220],... 

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