Phthalocyanines dendrimers

Polyethyleneimine (PEI) (with reporter dendrimer-phthalocyanine TPPS2a, AlPcS2a... 

Quadruplicated cationic peptide (NLS) AlPcS2a Dendrimer-phthalocyanine... 

Camptothecin-loaded micelles In vivo experiments Dendrimer-phthalocyanine-loaded micelles... 

It has been shown that this catalyst is selective in epoxidation of linear alkenes the linear epoxide yield was two to four times higher than in catalysis by ordinary porphyrin. It was also demonstrated that, in catalysis by the dendrimers, cyclic alkenes are oxidized three times more rapidly than similar linear 1-alkenes are. The catalyst activity decreases only by 10% at a turnover number (TON) of 1000, which is much higher than that for the monomolecular analogue. A cobalt complex with dendrimer phthalocyanine was much more stable, while remaining active, in... 

Herlambang S et al (2011) Disulfide crosslinked polyion complex micelles encapsulating dendrimer phthalocyanine directed to improved efficiency of photodynamic therapy. J Control Release 155 449 57. doi 10.1016/j.jcomel.2011.06.019... 

The effect of core shielding of a porphyrin moiety by peripheral dendrons has been carefully investigated on two series of Zn-phthalocyanine-cored dendrimers with aryl-ether branches [60]. Generation 0,1, and 2 (dendrimer 27) species, terminated with ester groups, are soluble in organic solvents, while the species terminated with carboxylate units (e.g., 28) are soluble in water. 

A poly(propylenamine) dendrimer (11, Fig. 6.37) functionalised with poly-(N-isopropylacrylamide) (PIPAAm) (see Section 4.1.2) was used as dendritic host for anionic cobalt(II)-phthalocyanine complexes (a, b) as guests, which are held together by supramolecular (electrostatic and hydrophobic) interactions [57]. These dendritic complexes were investigated as catalysts in the above-mentioned oxidation of thiols, where they show a remarkable temperature dependence the reaction rate suddenly increases above 34°C. One attempted explanation assumes that the dendritic arms undergo phase separation and contraction above the Lower Critical Solubility Temperature (LCST). At this temperature the phthalocyanine complex site is more readily accessible for substrates and the reaction rate is therefore higher. 

Besides these classical aromatics and polyaromatic hydrocarbons, other very important classes or arene molecules are porphyrins [60, 61], phthalocyanins [61, 62], porphycens [63], calixarenes [64], resorcarenes [64], cydophanes [47], dendrimers [65], elementa-arenes [66], organometallic arene (hexahapto) [67], benzyne (dihapto), and aryl- and benzyl (monohapto) complexes [68], inorganic pyridine and polypyridine complexes [69], fullerenes [70, 71], and... 

A phthalocyanine core was functionalized with four, eight, and 16 ferrocenyl units (compounds 49-51) [67]. Cyclic voltammetry experiments in DMF or CH2CI2 showed the presence of many quasi-reversible waves. All the ferrocenyl units behave independently, giving rise in all three compounds to a single oxidation wave, which is accompanied by one or two oxidation and by two or three reduction processes due to the phthalocyanine rt-system. For 51, the presence of a stripping peak indicates precipitation of the oxidized product in CH2CI2, as often observed in ferrocene-functionalized dendrimers (see Section 9.4.1). 

A similar quenching by methylviologen through the dendrimer architecture was also observed in the Zn-phthalocyanine-cored dendrimer 54 [125]. 

The fluorescence of the zinc-phthalocyanine core in dendrimer 49 is completely quenched [67]. On the basis of energetic considerations, this quenching process was attributed to electron transfer from the connected ferrocenyl units to the excited phthalocyanine core. The photophysical behavior of 50 and 51 was not mentioned. 

Phthalocyanines and their metal complexes have interesting catalytic, electronic, and optical properties.172 Kimura et al.173 synthesized a phthalocyanine-centered dendrimer possessing Newkome-type dendrons,174 and subsequently used the second-generation cobalt-metalated phthalocyanine dendrimer as the catalyst for the oxidation of mercaptoethanol by dioxygen... 

FIGURE 5.6 Metallated phthalocyanine-cored dendrimers with eight arms as described by Majoral and coworkers. 

Topics which have formed the subjects of reviews this year include excited state chemistry within zeolites, photoredox reactions in organic synthesis, selectivity control in one-electron reduction, the photochemistry of fullerenes, photochemical P-450 oxygenation of cyclohexene with water sensitized by dihydroxy-coordinated (tetraphenylporphyrinato)antimony(V) hexafluorophosphate, bio-mimetic radical polycyclisations of isoprenoid polyalkenes initiated by photo-induced electron transfer, photoinduced electron transfer involving C o/CjoJ comparisons between the photoinduced electron transfer reactions of 50 and aromatic carbonyl compounds, recent advances in the chemistry of pyrrolidino-fullerenes, ° photoinduced electron transfer in donor-linked fullerenes," supra-molecular model systems,and within dendrimer architecture,photoinduced electron transfer reactions of homoquinones, amines, and azo compounds, photoinduced reactions of five-membered monoheterocyclic compounds of the indigo group, photochemical and polymerisation reactions in solid Qo, photo- and redox-active [2]rotaxanes and [2]catenanes, ° reactions of sulfides and sulfenic acid derivatives with 02( Ag), photoprocesses of sulfoxides and related compounds, semiconductor photocatalysts,chemical fixation and photoreduction of carbon dioxide by metal phthalocyanines, and multiporphyrins as photosynthetic models. 

Macrocyclic metal complexes are the principal materials incorporated in the dendrimer structure (for reviews see [192,193]). Examples are metallo dendrimers with a porphyrin core [194-204], with a phthalocyanine core [205-209], with crown ethers in the repeat unit [210-212] or with a cyclic amine core [213],... 

The possibility of using the thermotropic properties of macromolecular complexes of dendrimers was demonstrated by the example of oxidation of disulfides in the presence of a macromolecular complex of cobalt phthalocyanine with a polyisopropylacrylamide-based (PIPAAm-based) dendrimer characterized by temperature-dependent solubility. The oxidation rate is almost tripled by increasing the temperature from 34 to 36 °C [129]. These temperatures are close to... 

A Phthalocyanine-Based Dendrimer for Harvesting Low-Energy Photons or for Photoinduced Electron Transfer Reactions... 

Figure 5.11 Structure of a conjugated dendrimers, star-shaped stilbenoid phthalocyanines [54]. (Reproduced with permission.)...

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