Nanotube supramolecular complexes

Ali-Boucetta H, Al-Jamal KT, McCarthy D, Prato M, Bianco A, Kostarelos K (2008) Multiwalled carbon nanotube-doxorubicin supramolecular complexes for cancer therapeutics. Chem. Commun. 459—461. 

Figure 8.10 Soluble supramolecular complexes of carbon nanotubes, 0.01 M Na2S04, aqueous solution. Scan rate = 0.1 V/s T— 25°C working electrode is Pt disc (r — 0.05 cm). Potentials measured versus silver quasi-reference electrode (approximately —0.05 V versus SCE). Ref. 121, Reproduced by permission of the Royal Society of Chemistry.

FIGURE 2.2 Supramolecular nanostructures for light driven energy and electron transfer. This research is focused on rational design and study of self-assembled porphyrin, fullerene, and carbon nanotube bearing supramolecular complexes and nanostructures. 

Noncovalent interactions with belt- or tube-like host molecules might also be suitable to a separation of carbon nanotubes by diameter. Cyclodextrines or beltshaped aromatic compounds could be named as examples here. They may not have proven their applicability as selective complexing agent yet, but considering their geometry reveals favorable dispositions for a discriminative interaction with certain nanotubes. Supramolecular arrangements with carbon nanotubes are also discussed in Section 3.5.7. 

Supramolecular chemistry typically involves the complexes based on molecular recognition, which include crown ethers, catenates, rotaxanes, etc. Azobenzene derivatives are often used as structural elements in such supramolecular assembly. Already in 1980 (Shinkai et ah, 1980), azobenzene moiety had been introduced into crown ether. Other recent examples include azobenzene-cyclodextrin complexes (Callari et ah, 2006), azobenzene-attached nanotube-cyclodextrin complexes (Descalzo et al., 2006), and molecular recognition complexes with DNA (Haruta et al., 2008). Numerous examples of photoswitch-able azobenzene supramolecular systems in solutions can be found (Yagai et al., 2005 Balzani et al., 2002). But there are no investigations in these systems concerning photoorientation and mass transport. 

The examples of DNA-based nanoactuators reviewed here demonstrate a wide variety of approaches and strategies for incorporation of controllable motions into DNA-based supramolecular complexes. This type of switchable molecular assembly will likely find future use in combination with other nanomaterials such as carbon nanotubes, metallic and semiconducting nanoparticles, and other electrically active components for construction of nanoelectronics for sensors applications, as one possible example. 

Similarly P-P, meso-meso, P-P triply linked dimers were obtained by Diederich and CO workers. They showed that such dimers led to weU-organized self-assembled networks on silver surfaces [162, 163]. Similar self-organized networks were observed for hybrid Ceo-triply linked dimer assemblies [162, 163]. Hybrid assemblies between single-walled carbon nanotubes (SWNTs) and triply linked trimers were also investigated and allowed the formation of stable supramolecular carbon nanotubes-porphyrin complexes [164]. 

Endohedral Fullerene Complexes, Nanotubes and Other Fullerene-based Supramolecular Systems... 

Metal-directed Self-assembly of Complex Supramolecular Architecture Chains, Racks, Ladders, Grids, Macrocycles, Cages, Nanotubes and Self-intertwining Strands (Helicates)... 

The uptake of C6o corresponds to the increase in absorbance at 258 and 328 nm in the absorption spectrum of 1 + C6o (Fig. 23). Comparison of a solution of 1 + C6o with a saturated solution of C60 in chloroform showed that the Cgo concentration increased 16-fold in the presence of NDI nanotubes (1). In contrast with these results, the methyl ester of 1, which is unable to form hydrogen-bonded supramolecular nanotubes, did not enhance the solubility of C60 in chloroform, supporting the thesis that the Cfi0 molecules are complexed in the inner nanotubular cavity. The increase in absorbance at 258 nm also led to an estimate of [NDI]/[C6o] stoichiometry, revealing that an average of 3.6 NDI units were encapsulating one Cfi0 molecule. Similar results were also obtained with other amino acid derivatives of NDI. 

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