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

Synthesis of chloro-carbonyl derivatives of rhenium, ruthenium, rhodium, iridium and platinum via reaction of the metal atoms with oxalyl chloride

New synthetic pathways in dicyclopent adienyltantalum chemistry

The ansa-rhenocene compound [Re{(η-C5H4)CMe2(η-C5H4)}Cl] 1 has been prepared by reaction of ReCl5 with [K2(C5H4)CMe2(C5H4)]. X-Ray crystallography shows the molecular structure to be unsymmetrical, with the angle defined by the Re-bridgehead carbon vector and the chlorine atom found to be 170.4°. A density functional study compares the electronic structure of [Re{(η-C5H4)CH2(η-C5H4)}Cl] with [Re{(η-C5H5)2Cl] and shows that for the ansa-bridged species, the chlorine binds less effectively in the central position. The calculated structure of [Re{(η-C5H4)CH2(η-C5H4)}Cl] is also found to be unsymmetrical.

Synthesis, structure and density functional study of the ansa-rhenocene complex [Re{(η-C5H4)CMe2(η-C5H4)}Cl]

Reduction of WCl6 with sodium amalgam in the presence of cycloheptatriene gives [W(η-C7H7)(η-C7H9)], which is a precursor to the compounds [W(η-C7H7)LX2], [W(η-C7H7)L2X], where L = tertiary phosphines or acetonitrile and X = halogen, [W(η-C7H7)(η-C5H4R)], R = H, Me, and [W(η-C7H7)(η-C9H7)].

η-Cycloheptatrienyl tungsten chemistry

The preparation and properties of the bis-π-allyl derivatives (C6H5R)Mo(π-C3H5)2 are described. The butadiene cation [C6H6Mo(π-C3H5)C4H6]+ reacts readily with nucleophiles (Nu = CN, OMe, SMe, H) to give the neutral π-allylic derivatives C6H6Mo(π-C3H5)(π-NuCH2C3H4).

Malcolm L. H. Green

Papers

Synthesis of chloro-carbonyl derivatives of rhenium, ruthenium, rhodium, iridium and platinum via reaction of the metal atoms with oxalyl chloride

New synthetic pathways in dicyclopent adienyltantalum chemistry

Synthesis, structure and density functional study of the ansa-rhenocene complex [Re{(η-C5H4)CMe2(η-C5H4)}Cl]

η-Cycloheptatrienyl tungsten chemistry

Arene molybdenum chemistry: some bis-π-allylic derivatives