Peapod formation

A special host- est geometry is realized in the so-caUed peapods. These are single-waUed carbon nanotubes with fuUerenes enclosed in their irmer void so they are arranged tike peas in their pod (also refer to Section 3.5.6). The embedded fuUerenes can be > as well as higher homologs. These may themselves contain endohedral guests, which turns peapod-formation reaUy into a super-supramo-... 

Endohedral peapod formation, intercalation of metal atoms, storage of hydrogen... 

So far, direct evidence of C60 hydrogenation inside of nanotubes from HRTEM imaging is absent. It is required as a decisive demonstration of possibility for hydrogen to penetrate inside of peapods but could possibly be challenging experimentally. Chemical reaction within nanospace of carbon nanotubes is possibly only first example of interesting nanoscale chemistry and fullerene hydrogenation in other exotic environments will possibly be successfully demonstrated in future. It is quite likely that hydrogenation in confined space results in formation of fulleranes with different molecular structures. 

Besides the substances mentioned so far, functionalized fuUerenes like the simple Bingel adduct can be intercalated into nanotubes as well (Section 2.5.5.2). The formation of peapods has further been described for metallocenes (e.g., ferrocene), porphyrines (e.g., erbium phthalocyanine complex) and small fragments of nanotubes. The most important prerequisite for the feasibility of inclusion is always a suitable proportion of sizes of both the tube and the structure to be embedded. For example, this effect can be observed for the intercalation of different cobaltocene derivatives into SWNT. The endohedral functionalization only takes place at an internal diameter of 0.92nm or above (Figure 3.100). But there is also an upper limit to successful incorporation. When the diameter of the nanotube is too large, the embedded species can easily diffuse away again from the host. Only few molecules are consequently found inside such a wide tube. 

Electroformation allows the formation of giant vesides as large as 100 mm in diameter, induding some unusual multicompartment and multilayered stractures where vesides are encapsulated inside larger vesides in a peapod- or onion-like fashion. ... 

Su HB et al (2007) Simulations on the effects of confinement and Ni-catalysis rai the formation of tubular fullerene structures from peapod precursors. Phys Rev B 75(13) 134107-(5)... 

Iwamoto T, Watanabe Y, Sadahiro T, Haino T, Yamago S (2011) Size-selective encapsulation of C60 by [lOjcycloparaphenylene formation of the shortest fullerene-peapod. Angew Chem Int Ed 50(36) 8342-8344... 

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