Ruthenium phthalocyanine complexes

The ruthenium phthalocyanine complex (54) shows a visible absorption band at 650 nm (6-49,000 cm" ) and a phosphorescence band located at 895 nm. 

Other reactions of small inorganic molecules are the oxidation of chloride ion at a Nafion electrode impregnated with a ruthenium 0x0 complex and the reduction of nitrogen monoxide to ammonia at a Co phthalocyanine modified electrode... 

Several examples of carbene complexes have been structurally characterized (Fig. 5), and selected data for Ru(TPP)(=C(C02Et)2)(Me0H). Os(TTP)-(=C(p-C(,H4Me)2)(THF), Os(TTP)(=CHSiMe2)(THF), Os(TTP)(=SiEt2THF)-(THF) and a /x-carbido phthalocyanine complex, Ru(Pc)(py)]2C, are given in Table The ruthenium carbene complex has a Ru=C bond signifi-... 

The X-ray structure of zinc naphthalocyanate has been determined with Zn—N bond lengths of 1.983(4) A.829 Pentanuclear complexes with a zinc phthalocyanine core and four ruthenium subunits linked via a terpyridyl ligand demonstrate interaction between the photoactive and the redox active components of the molecule. The absorbance and fluorescence spectra showed considerable variation with the ruthenium subunits in place.830 Tetra-t-butylphthalocyaninato zinc coordinated by nitroxide radicals form excited-state phthalocyanine complexes and have been studied by time-resolved electron paramagnetic resonance.831... 

Other workers have employed different sensitiser systems, e.g. duel sensitisation by a zinc porphyrin and copper phthalocyanine on TiOj, Eosin Y or tetrabro-mophenol blue on ZnO, and a ZnO/SnOj mixture with a ruthenium bipyridyl complex, to produce good energy conversion factors. 

Both phthalocyanines and porhyrins are very promising sensitizers for wide band gap semiconductors. DSSCs fabricated from these kind of sensitizers present overall power conversion efficiency as high as 7%, which is still smaller than that achieved by the ruthenium polypyridyl complexes though, but higher than most of other dyes. The multiplicity on the molecular structure modification of these compounds provides a great potential for further promotion on their sensitization properties. The research in this field is still far from systematic and comprehensive and quantitatively much less than the researches on polypyridyl ruthenium complexes. But... 

Zeolite-encapsulated perfluorinated ruthenium phthalocyanines catalyze the oxidation of cyclohexane with t-BuOOH [146]. A dioxoruthenium complex with a D4-chiral porphyrin ligand has been used for the enantioselective hydroxylation of ethylbenzene to give a-phenylethyl alcohol with 72% e.e. [147]. 

Figure 14. (a) Structure of a zeolite-entrapped perfluorinated ruthenium phthalocyanine (RuFi6Pc) complex used in epoxidation reactions, (b) Comparison of turnover numbers for cyclohexane oxidation using ruthenium phthalocyanine (RuPc), RuFi Pc and zeolite X-entrapped RuFi Pc. 

The use of metal phthalocyanine compounds has also been described (66,67). The catalysts can either be supported on an inert carrier or used in a liquid-liquid two-phase system. Various functionalized phthalocyanine ruthenium complexes have been mentioned for the reaction of interest. For instance, ruthenium phthalocyanine disulfonate transformed hept-3-ene into 3- -propylpentanol (80°C, 18 hours, 120 bar) in a two-phase system. Further details (67) on the preparation of metal complexes supported on silica- and alumina-type supports have appeared. Generally, a mixture of metal phthalocyanine sulfonate and hydrated alumina pro-... 

Iron-phthalocyanine (Fe-Pc) encapsulated in Y and VPI-5 zeolites were used for the oxidation of alkanes or olefins in presence of t-butylhydroperoxide or H2O2 (Fig. 9). Fe-Pc-Y also catalyzed the oxidation of cyclohexane to cyclohexanol and cyclohexanone with t-butylhydroperoxide ( TBHP ). Ruthenium perfluorophthalocyanine complexes encapsulated in NaX ( Ru-Fi6 Pc-X ) were active for the oxidation of cyclohexane with TBHP at room temperature.Manganese(II) bipyridyl complexes in faujasite ( Y ) zeolite are active for the oxidation of cyclohexene to adipic acid in the presence of H2O2 at room temperature. Similarly oxidation reactions have been reported using copper complexes encapsulated in X,Y, and VPI-5 molecular sieves. 

Synthesis, properties, and applications of ruthenium phthalocyanine and naphthalocyanine complexes 07CCR1128. 

Phthalocyanine complexes within zeolites have also been prepared by the ship-in-a-bottle method (see Section 6.6), and have subsequently been investigated as selective oxidation catalysts, where their planar metal-N4 centres mimic the active sites of enzymes such as cytochrome P450, which is able to oxidize alkanes with molecular oxygen. Cobalt, iron and ruthenium phthalocyanines encapsulated within faujasitic zeolites are active for the oxidation of alkanes with oxygen sources such as iodosobenzene and hydroperoxides. Following a similar route, Balkus prepared Ru(II)-perchloro- and perfluorophthalocyanines inside zeolite X and used these composites for the selective catalytic oxidation of alkanes (tert-butylhydroperoxide). The introduction of fluorinated in place of non-fluorinated ligands increases the resistance of the complex to deactivation. 

Preliminary results of the reaction between vanadium(iii)-tetrasulpho-phthalocyanine complex with oxygen have been reported these data were compared with those obtained for the corresponding reaction of the hexa-aquo complex ion. The oxidation of methyl ethyl ketone by oxygen in the presence of Mn"-phenanthroline complexes has been studied Mn " complexes were detected as intermediates in the reaction and the enolic form of the ketone hydroperoxide decomposed in a free-radical mechanism. In the oxidation of 1,3,5-trimethylcyclohexane, transition-metal [Cu", Co", Ni", and Fe"] laurates act as catalysts and whereas in the absence of these complexes there is pronounced hydroperoxide formation, this falls to a low stationary concentration in the presence of these species, the assumption being made that a metal-hydroperoxide complex is the initiator in the radical reaction. In the case of nickel, the presence of such hydroperoxides is considered to stabilise the Ni"02 complex. Ruthenium(i) chloride complexes in dimethylacetamide are active hydrogenation catalysts for olefinic substrates but in the presence of oxygen, the metal ion is oxidised to ruthenium(m), the reaction proceeding stoicheiometrically. Rhodium(i) carbonyl halides have also been shown to catalyse the oxidation of carbon monoxide to carbon dioxide under acidic conditions ... 

The synthesis and properties of ruthenium phthalocyanines, RuPcs, have been well studied over the last 30 years, but only recently they have been rediscovered for their potential application in metallosupramolecular chemistry. Basically, RuPcs are different from ZnPcs in their tendency to form stronger complexes with basic sp nitrogen atoms (pyridine and imidazole) and in the possibility to form complexes on one side or on both sides of the macrocycle. Another interesting point of ruthenium phthalocyanines resides in the longer lifetime of their radical-ion-pair state when compared to that of zinc phthalocyanines. Thus, all things being equal, RuPcs display a richer potential for supramolecular chemistry than ZnPcs. 

The synthesis of ruthenium-metallated Pc derivatives using Ru3(CO)i2 in benzonitrile afforded ruthenium phthalocyanines either monocoordinated with CO or dicoordinated with benzonitrile. Cook and colleagues were the first to predict their utility in the preparation of further (pyridyl) ligated derivatives and showed that it was indeed straightforward. This chemistry is sufficiently robust and efficient to permit elaborate supramolecular complexes to be prepared, as demonstrated by the synthesis of porphyrin-phthalocyanine multichromophores 21 and 22, as illustrated in Figure 15. The absorption spectra of these arrays are essentially the sums of spectra of the starting materials. These observations indicate that there is little ground-state electronic interaction between the perpendicular maaocycles, in accordance with previous results published by Ng and Li (Section 4.1.1). ... 

The complexes frans-[Ru(NH3)4 P(OR)3 2] and trans-[Ru(NH3)4 P(OEt)3 P(OR)3 ], with R = methyl, isopropyl, or butyl, aquate to give a monophosphite product with rate constants which vary little with the nature of the complex or solvent composition (up to 80% ethanol). The results support the dissociative mechanism previously proposed for the triethyl phosphite complex. Trans effects are here dominated by 7T acceptor properties of these phosphite ligands. Trans effects in substitution in bis-ligand ruthenium (and iron) phthalocyanine complexes follow the order... 

Christendat D, David MA, Morin S, Lever ABP, Kadish KM, Shao J (2005) Synthesis and characterization of highly soluble hexadecachloro- and hexadecafluorophthalocyanine ruthenium(II) complexes. J Porphyrins Phthalocyanines 09 626-636... 

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