Carbon nanotubes supramolecular interactions

Like the currently popular area, called nanoscience , the field of supramolecular chemistry has rather hazy boundaries. Indeed, both areas now share much common ground in terms of the types of systems that are considered. From the beginning, electrochemistry, which provides a powerful complement to spectroscopic techniques, has played an important role in characterizing such systems and this very useful book goes considerably beyond the volume on this same topic by Kaifer and Gomez-Kaifer that was published about 10 years ago. Some of the classic supramolecular chemistry topics such as rotaxanes, catenanes, host-guest interactions, dendrimers, and self-assembled monolayers remain, but now with important extensions into the realms of fullerenes, carbon nanotubes, and biomolecules, like DNA. 

Supramolecular Interactions of Phthalocyanines with Carbon Nanotubes... 

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 interactions were also utilized in synthesis of carbon nanotube/poly-propylene composites (see chapter Applications of Ball Milling in Nanocarbon Material Synthesis). Solid-state grafting of maleated polypropylene on the surface of multiwalled carbon nanotubes (MWCNTs) employs interactions of carbonyl and carboxyl groups with maleic anhydride groups via hydrogen bonds or other dipole-dipole interactions [8]. 

Figure 9.4 Surface properties and size influencing the pathways of CNT internalization. Inserted panel Nanotube bundles (CNT)., functionalized with (macro)molecules (f) with the aid of sonication (US) and/or temperature (T), are dispersed in single nanotubes f-CNT this f-CNT can lead to the formation of supramolecular structure p f-CNT. (al) (CNT). interact with cell membrane and are internalized via phagocytosis (bl) f-CNT enter the cells by diffusion (b2) nanotube dispersion is not stable and nanotubes cluster in solution (nanotube clusters enter the cell by phagocytosis) (cl) p f-CNT enters the cell by ligand-receptor (1) binding (c2) p f-CNT cluster on cell membrane and enter by receptor-mediated endocytosis. CNT Carbon nanotube f-CNT Functionalized CNT.

The chapter Supramolecular Information/Programming from a Boolean Perspective, Concepts delves deeper into the reversible covalent bond toolbox. The equilibration of these strong covalent bonds, often referred to as dynamic covalent chemistry, is kineticaUy slower in comparison to weaker noncovalent interactions and often requires a catalyst. An extreme example might also include the formation of carbon nanotubes and fullerenes. While not spontaneous at room temperature, carbon vapor at high temperature does assemble to form these intricate and beautiful stractures. 

Figure 1 Chemical functionalization of carbon nanotubes (CNTs) involves the covalent bonding of a variety of chemical groups (R) to the graphitic lattice of CNTs. Supramolecular approaches can, in principle, enable the attachment of the same functionality (R) throngh nondestructive noncovalent interactions to CNTs in both an exohedral and endohedral fashion.

The elaboration of organometallic networks and supramolecular assemblies, assembled via directional dirhodium-x-arene interactions [72,153], is important due to the relevance of alkene coordination to the dirhodium core in cyclopropanation reactions, and thus their applications in catalysis. Also, they are relevant to the Issues of x-arene interactions encountered in fullerene and carbon nanotubes [154], in hydrogen storage and fuel cell technology. 

Lee, Y, Geckeler, K. E. (2012). Cellular interactions of a water-soluble supramolecular polymer complex of carbon nanotubes with human epithelial colorectal adenocarcinoma cells. Macromolecular Bioscience, 12, 1060-1067. 

These n interactions can be equally critical in materials chemistry applications, including self-assembled supramolecular architectures.For example, molecular wires can be formed from stacks of aromatic macrocycles.The binding of small molecules to carbon nanotubes and attraction between graphene sheets are both determined by noncovalent n interactions. The crystal structure and charge-transport properties of 7t-conjugated organic materials are also largely determined by n-n interactions. ... 

Cheng F, Zhang S, Adronov A, Echegoyen L, Diederich F (2006) Triply fused Zn -porphyrin oligomers synthesis, properties, and supramolecular interactions with single-walled carbon nanotubes (SWNTs). Chem Eur J 12 6062-6070... 

PLDL did not have covalent characteristics. It may suggest that in these nanocomposite samples the carbon nanotubes are located between the polymer chains and probably have an influence on the supramolecular structure of polylactide during solidification as a result of the interaction of secondary bonding. 

The final chapter, Heterocyclic Supramolecular Chemistry of Fullerenes and Carbon Nanotubes by N. Komatsu presents an extremely unique review that focuses on the noncovalent chemistry of fullerenes and carbon nanotubes with nitrogen- and/or oxygen-containing heterocyclic molecules such as porphyrin, DNA, protein, peptide, and carbohydrate. Not only exohedral but also endohedral fimctionahzation is reviewed, because the above guest molecules can interact with both faces of the carbon nanotubes. The hurdles in structural separation, nanofabrication, and bioappHcations of carbon nanotubes will hopefully be addressed by the supramolecular strategy. 

---