Porphyrin, side-chain polymer

The chlorination of [MePhSi]n leads to a reactive group that is remote with respect to the main silicon chain. It is possible to modify the resulting functional polysilane in many ways. For example, recently Sakata and his research group have utilized this approach to anchor tetraphenylporphyrin units as pendant groups on the polysilane backbone (Fig. 7.21). It was observed that in this polymer an intramolecular charge transfer occurs from the silicon main-chain to the porphyrin side-chain [66]. 

New porphyrin-containing Group IVB polymers were made using ricinoleic acid215 or hematoporphine IX.210,217,218 Polymer 93 is a representative example that was used as a selective chelating agent. Macrocyclic tetrapyrrole has four methyl, two ethanolic, and two propionic acid side chains. The polymers are cross-linked because of the four reactive functions (two acid and two alcohol groups). The adsorption of Ni+2 by porphyrin moieties was observed for the titanium polymer. 

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... 

Polymers with porphyrin units in the main chain and fuUerene side groups are described as electroactive [113], as well as polymers with azo-groups in the main chain [114] and triarylamines in the side chain [115-118]. By proper functionalization and architecture, even poly(thiophene) [119] and oligoaniline [120-122] and derivatives [123] become soluble in different solvents. Also, electroactive polymers derived from 2,2,6,6-tetramethyl piperidinyloxyl (TEMPO) have drawn attention, especially with respect to energy storage apphcations [124—127]. 

M. Kamachi, X. S. Cheng, T. Kida, A. Kajiwara, M. Shibasaka, and S. Nagata, Synthesis of new polymers containing porphyrins in their side chains radical polymerizations of 5-[4-(acryloyloxy)phenyl]-10,15,20-triphenylporphyrin, Macromolecules, 20, 2665 (1987). 

Fe(III)-protoporphyrin-IX-dimethylester (7d) (0.03 mol%) was copolymerized with 7-conjugated monomers like styrene or methyl methacrylate in bulk and acrylamide in methanol using radicalic initiators Increasing the ratio of [7d]/[styrene] the molecular weight decreased (Table 3) indicating a chain transfer efiect of the porphyrin (chain transfer coeffident C,= 2.3). On the other side the content of covalent bond is increasing (Table 3). Therefore it is supposed that the observed reduction of Fe(III) to Fe(II) led to an addition of one porphyrin only at the chain end to give the polymer (34) (Eq. 14). 

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