Porphyrins nanotube attachment

Esterification constitutes a valuable alternative to the amidation strategy. As with amidation, the formation of the ester bond is performed following a first reaction step with acyl chloride. The ester bond has been extensively utilized to attach many organic and inorganic moieties. Porphyrins are a classic example of substrates covalently bound via esterification strategies their photoinduced electron transfer to the nanotube has been studied for applications in molecular electronics and photovoltaic devices (Fig. 3.6) [21]. 

Most supramolecular nanotube modifications involve noncovalent interactions on the external surface of the CNT (i.e., exohedral. Figure 1). For example, n-n stacking is employed to attach pyrene " and porphyrin " molecules to the surface of CNTs. Hydrophobic and van der Waals interactions are necessary for micelle-forming compounds (i.e., surfactants and lipids ) and polymer (both syn-thetic " and natural ) to functionalize CNTs. The so-called r-cation interactions represent an additional exohedral approach for functionalizing CNTs. Finally, organometallic bonding is required for the decoration of CNT with metal nanoparticles (NP) at defect sites. ... 

Porphyrin-based complexes pass their redox sensitivity on to the corresponding polymers. Advanced conjugated main-chain structures with attached dendrons have been introduced [220]. Grafting of porphyrin-zinc main-chain polymers onto carbon nanotubes was reported [221]. An interesting example dealing with a nonelectrochemically switched polymer was recently given. Here, polymers with porphyrin-iron end groups could be switched between linear and cyclic polymers by a dimerization procedure (Fig. 14) [222, 223],... 

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