CARBON nanotubes1 are expected to have a wide variety of interesting properties. Capillarity in open tubes has already been demonstrated2–5, while predictions regarding their electronic structure6–8 and mechanical strength9 remain to be tested. To examine the properties of these structures, one needs tubes with well defined morphologies, length, thickness and a number of concentric shells; but the normal carbon-arc synthesis10,11 yields a range of tube types. In particular, most calculations have been concerned with single-shell tubes, whereas the carbon-arc synthesis produces almost entirely multi-shell tubes. Here we report the synthesis of abundant single-shell tubes with diameters of about one nanometre. Whereas the multi-shell nanotubes are formed on the carbon cathode, these single-shell tubes grow in the gas phase. Electron diffraction from a single tube allows us to confirm the helical arrangement of carbon hexagons deduced previously for multi-shell tubes1.

Single-shell carbon nanotubes of 1-nm diameter

The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.

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Carbon Nanotubes: Present and Future Commercial Applications

Nanoparticles — particles in the size range 1–100 nm — are emerging as a class of therapeutics for cancer. Early clinical results suggest that nanoparticle therapeutics can
show enhanced efficacy, while simultaneously reducing side effects, owing to properties such as more targeted localization in tumours and active cellular uptake. Here, we
highlight the features of nanoparticle therapeutics that distinguish them from previous anticancer therapies, and describe how these features provide the potential for
therapeutic effects that are not achievable with other modalities. While large numbers of preclinical studies have been published, the emphasis here is placed on preclinical and clinical studies that are likely to affect clinical investigations and their implications for advancing the treatment of patients with cancer.

Nanoparticle therapeutics: an emerging treatment modality for cancer

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

Carbon nanotubes have hollow interiors with internal diameters ranging from 0.5 – 20 nm although more typically 1 – 4 nm. It is now well established that these internal cavities can be filled with crystalline and molecular materials. Filling of single walled carbon nanotubes (SWNTs) are normally filled by direct mixing of the molten filling material and the nanotubes at elevated temperature. Characterisation of filled carbon nanotubes relies mainly on high-resolution transmission electron microscopy (HRTEM) and extended resolution HRTEM techniques. The crystals formed within the narrower SWNTs are often only a few atoms in cross section with a large proportion of atoms lying on the surface of the encapsulated crystals. An extreme example is in the case of a 2 × 2 crystal of potassium iodide which is effectively an ‘all surface’ crystal. The structures of the nanocrystals encapsulated inside SWNTs show other significant differences compared to the corresponding bulk materials. For example, inter-atomic differences can be substantially greater (i.e. by as much as ~20%) for SWNT encapsulated materials. Several examples of filled SWNTs are described including those filled with simple metal halide salts, covalent metal halides and molecular species as in o-carborane.

Synthesis and Structural Characterisation of Single Wall Carbon Nanotubes Filled with Ionic and Covalent Materias

Einige alkyl-, acetyl-, aryl- und benzoyl-derivate des wolframs

NEW SYNTHETIC ROUTE TO MONO-η5-CYCLOPENTADIENYLMOLYBDENUM COMPOUNDS- X-RAY CRYSTAL STRUCTURE OF (η-C5H5)MO(PH2PCH2CH2PPH2)(η-C6H89)(PF6).SO2

Rare-earth pyrochlores of general formula Ln2Sn2O7(Ln = rare-earth) are found to be active catalysts for the oxidative coupling of methane, with enhanced conversion to useful hydrocarbons, particularly ethene, being observed at 1150 K for those rare-earths that exhibit mixed valence behaviour (Ln = Pr, Sm, Eu, Tb, Tm, and Yb).

Oxidative Coupling of Methane over Tin-Containing Rare-Earth Pyrochlores.

Methods for the production on a synthetically useful scale of atoms,unstable radicals and molecular species which are only stable in the gas phase are briefly reviewed. Apparatus for synthesis using atoms of even the most refractory metals is described. New chemistry derived from these techniques is presented.

Malcolm L. H. Green

Papers

Synthesis and Structural Characterisation of Single Wall Carbon Nanotubes Filled with Ionic and Covalent Materias

Einige alkyl-, acetyl-, aryl- und benzoyl-derivate des wolframs

NEW SYNTHETIC ROUTE TO MONO-η5-CYCLOPENTADIENYLMOLYBDENUM COMPOUNDS- X-RAY CRYSTAL STRUCTURE OF (η-C5H5)MO(PH2PCH2CH2PPH2)(η-C6H89)(PF6).SO2

Oxidative Coupling of Methane over Tin-Containing Rare-Earth Pyrochlores.

Metal atoms in synthesis and related aspects