Fullerenes porphyrin polymers

Figure 5.56 Schematic illustrating the self-assembled multilayers of sodium 3-mercaptoethane-sulfonate (layer 1 ), hexacationic homooxacalix[3]arene-fullerene (2 1) complex (layer 2 ), with either the anionic porphyrin polymer ( 3 ) or its zinc porphyrin analogue ( 4 ) forming the third layer. Reprinted with permission from A. Ikeda, T. Hatano, S. Shinkai, T. Akiyama and S. Yamada, /. Am. Chem. Soc., 123,4855 (2001). Copyright (2001) American Chemical Society...

Another example of self-assembly of porphyrin-containing polymer was illustrated by Li et al.73 Polyacetylene functionalized with fullerene and zinc porphyrin pendant groups were synthesized by polymerizing the corresponding fullerene/porphyrin substituted alkyne monomers with rhodium(I) norbomadiene catalyst (Scheme 5.5).74 Polymers with different ratio of C60 and porphyrin were synthesized. The polymers showed photocurrent response when the thin films were irradiated with white light, which was due to the electron transfer from the photo-excited porphyrin to the C60 units. In addition, the copolymers aggregated into ellipse-shaped nanorod structures with a diameter of approximately 100 nm and a length of... 

Fig. 6 Schematic view of the photoactive multilayers of sodium 3-mercaptoethane-sulfonate (first layer), fullerene-cationic homooxa-calix[3]arene inclusion complex 2 (second layer), anionic porphyrin polymer 3 or 4 (third layer) on an ITO electrode [82].

Fullerene-containing supramolecular polymers based on DNA templating have been reported by Chu and coworkers [96]. Cationic [60]fullerene derivahves bind onto the DNA main chain through Coulombic interachons, which gives rise to the polymeric nano-array of [60]fullerene. Shinkai and coworkers have reported photocurrent generation in a supramolecular fullerene polymer [97]. A [60]fullerene/ porphyrin/DNA ternary complex is deposited on an ITO (indium tin oxide) electrode by oxidative polymerization of E DOT. The effechve photocurrent generation is observed by light excitation of the porphyrin. 

Organic solar cell based on fullerene modified by heterocycles, porphyrin systems, and polymers with heterocyclic fragments 04MI53. 

Fullerene-Doped Polyvinylcarbazole. Fullerenes are known to be good electron acceptors. In the presence of electron donors such as aromatic amines, weakly bonded charge-transfer complexes can be formed [115]. Through virtual excitation, the existence of charge-transfer interaction can enhance the second-order optical nonlinearity of fullerenes [116], With direct excitation, excited state electron transfer between fullerenes and various electron donors such as aromatic amines [115,117], semiconductor colloids [118], porphyrin [119], and polymers [101, 103, 120] can occur. This electron-accepting property led to the development of fullerene-doped polymeric photoconductors [101,103]. 

The association of porphyrin and fullerene electron acceptors in LB films can also proceed via a stepwise, noncovalent formation of the assembly, as demonstrated by Shinkai and Ikeda (Figure 13.88). The host-guest interaction of Ceo with homooxa-calix[3]arene is the noncovalent interaction that assists film formation The fullerene absorption in the host-guest complex is used to determine a surface concentration of 1.4 x 10 ° molcrn" in the Ceo layer, which is then further covered with the polymer-sustained porphyrins 165 or 166. Porphyrin surface concentrations are then controlled by UV-visible absorption and are found to be 7.6 X 10 and 5.5 x 10 for 165 and 166, respectively. Photocurrent measurements performed under irradiation at 420 nm, with a 1.36 mW cm for a coating of 165, and at 430 nm, with a 1.53mWcm for a coating of 166, in... 

A significant research effort has been devoted to the design and application of various supramolecular self-assembled systems in photoelectrochemical solar cells. Fullerenes, fullerene derivatives, and carbon nanotubes are typically used as electron acceptor components of such systems. Porphyrins, phthalocyanines, ruthenium complexes, conjugated oligomers, and polymers are applied as electron donor counterparts. 

This approach mimics in some way dye sensitized solar cells because porphyrin/fuUerene clusters serve as sensitizers for buffer tin oxide (Sn02). At the same time, mixed fuUerene/polymer nanostructures resemble bulk heterojunction solar cells since donor (porphyrin) and acceptor (fullerene) molecules are blended together in the active layer. 

Supramolecular assemblies including CNTs have proven difficult due to challenges associated with dispersing SWNTs in neat solvents and to the difficulty in controlling molecular orientation. In one example of supramolecular assembly, a direct current (DC) electric field was employed to induce surfactant (tetraoctlyammonium bromide) or polymer (Nafion) capped SWNTs to assemble into linear bundles. On the basis of the knowledge that fullerenes can experience charge-transfer interactions with porphyrins to form supramolecular assemblies, Kamat and coworkers determined that protonated porphyrins yielded ordered... 

Other examples include aromatics, heterocycles, highly conjugated molecules (dyes), porphyrins, pthalocyanines, fullerenes, polymers and biological compounds (phosphohpids, pigments, peptides, and proteins). 

Angiolini L, Benelli T, Cocchi V et al (2013) Side chain porphyrin moiety linked to polymer-fullerene composite solar cell. React Funct Polym 73(9) 1198-1206... 

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