Chemical transformations, inside carbon

Botka B, Fiistos ME, Tohati HM, Nemeth K, Klupp G, Szekrenyes Z, Kocsis D, Utczas M, Szekely E, Vaczi T, Tarczay G, Hackl R, Chamberlain TW, Khlobystov AN, Kamaras K. Interactions and chemical transformations of coronene inside and outside carbon nanotubes. Small 2014 10 1369-78. 

Pure substances can themselves be divided into two types elements and compounds. Copper is an example of an element, a substance that cannot be broken down into simpler substances. The graphite in pencils is also an element—carbon. No chemical transformation can decompose graphite into simpler substances it is pure carbon. All known elements are listed in the periodic table in the inside front cover of this book and in alphabetical order on the inside back cover of this book. 

In these reactions, a er-bond is formed at the expense of two re-bonds and, thus, the process leads to a net loss of one chemical bond that is intrinsically unfavorable thermodynamically. Formation of the new er-bond leads to ring closure, whereas the net loss of a bond leads to the formation of two radical centers, which can be either inside (the endo pattern in Scheme 1) or outside of the newly formed cycle (the exo pattern). Note that er-radicals are formed through the endo path, while exo-closures may produce either a er-radical when a triple bond is involved or a conjugated re-radical when the new bond is formed at the central carbon of an allene. The parent version of this process is the transformation of enediyne 1 into p-benzyne diradical2 (the Bergman cyclization), shown in Scheme 2. 

It was shown how both endohedral and exohedral fullerenes can be inserted in nanotubes. In the peapods containing endohedral fullerenes (for instance Ce Cg2), HRTEM images showed interesting rotation and translation motion of the trapped spheroids. Exohedral metallofullerenes, CsC io have been synthesized and successfully encapsulated into SWCNTs via a new chemical reduction of Cgo molecules into anions. The addition of iodine to already prepared peapods allowed the coalescence of Cgo directly inside the nanotubes. Indeed, after heating at 550 C, iodine-doped peapods, inside the Cgo molecules molecules have been transformed in a tubular structure. Khlobystov et al. were able to perform reactions on the inner surface of carbon nanotubes in the presence of catalyti-cally active atoms of rhenium and monitor the whole process via HRTEM. ... 

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