Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

We predict the stability of an extended two-dimensional hydrocarbon on the basis of first-principles total-energy calculations. The compound that we call graphane is a fully saturated hydrocarbon derived from a single graphene sheet with formula CH. All of the carbon atoms are in $s{p}^{3}$ hybridization forming a hexagonal network and the hydrogen atoms are bonded to carbon on both sides of the plane in an alternating manner. Graphane is predicted to be stable with a binding energy comparable to other hydrocarbons such as benzene, cyclohexane, and polyethylene. We discuss possible routes for synthesizing graphane and potential applications as a hydrogen storage material and in two-dimensional electronics.

Graphane: A two-dimensional hydrocarbon

Carbon nanotubes can be functionalized via amidation and esterification of the nanotube-bound carboxylic acids. The solubility of these functionalized carbon nanotubes makes it possible to characterize and study the properties of carbon nanotubes using solution-based techniques. Representative results concerning the solubility, dispersion, defunctionalization, and optical properties of the functionalized carbon nanotubes are presented. Several examples for the use of functionalized carbon nanotubes in the fabrication of polymeric carbon nanocomposites, the probing of nanotube-molecule interactions, and the conjugation with biological species are highlighted and discussed.

Functionalized Carbon Nanotubes: Properties and Applications

In this Account we highlight the experimental evidence in favor of our view that carbon nanotubes should be considered as a new macromolecular form of carbon with unique properties and with great potential for practical applications. We show that carbon nanotubes may take on properties that are normally associated with molecular species, such as solubility in organic solvents, solution-based chemical transformations, chromatography, and spectroscopy. It is already clear that the nascent field of nanotube chemistry will rival that of the fullerenes.

Chemistry of single-walled carbon nanotubes.

In this review article, we explore covalent chemical strategies for the functionalization of carbon-nanotube surfaces. In recent years, nanotubes have been treated as chemical reagents (be it inorganic or organic) in their own right. Indeed, from their inherent structure, one can view nanotubes as sterically bulky, π-conjugated ligands, or conversely as electron-deficient alkenes. Hence, herein we seek to understand, from a structural perspective, the breadth and types of reactions single-walled nanotubes (SWNTs) can undergo in solution phase, not only at the ends and defect sites but also along the sidewalls. Controllable chemical functionalization suggests that the unique electronic and mechanical properties of SWNTs can be tailored in a determinable manner. Moreover, prevailing themes in nanotube functionalization have been involved with dissolution of tubes.

Covalent Surface Chemistry of Single-Walled Carbon Nanotubes

We have prepared hydrogenated single-wall and multiwall carbon nanotubes, as well as graphite, via a dissolved metal reduction method in liquid ammonia. The hydrogenated derivatives are thermally stable up to 400 °C. Above 400 °C, a characteristic decomposition takes place accompanied with the simultaneous formations of hydrogen and a small amount of methane. Transmission electron micrographs show corrugation and disorder of the nanotube walls and the graphite layers due to hydrogenation. The average hydrogen contents determined from the yield of evolved hydrogen correspond to the compositions of C11H for both types of nanotubes and C5H for graphite. Hydrogenation occurred even on the inner tubes of multiwall nanotubes as shown by the chemical composition and the overall corrugation. The thermal stability and structural results suggest the formation of C−H bonds in nanotubes and graphite.

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J.-P. Salvetat

Papers

Hydrogenation of carbon nanotubes and graphite in liquid ammonia