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

The new compounds [Re2(η-C6H6)(η-C6H8)2(µ-H)2], [Re(η-C6H6)(η-C6H8)H], [Re(η-C6H6)(η5-C7H7)], [Re(η-C6H6)(η5-C7H9)], and [Re(η5-C9H7)(η6-C9H8)] are described, including the determination of the crystal structures of the first two compounds. The new compounds have been made by co-condensation of rhenium atoms with benzene–cyclohexene, benzene–cyclohexa-1,3-diene (or cyclohexene), benzene–cycloheptatriene, benzene–cycloheptatriene, and pure indene, respectively. Co-condensation of rhenium atoms with benzene–cyclopentadiene yields a mixture of [Re(η-C6H6)(η-C5H5)] and [Re(η-C5H5)2H]. Characterisation of the η-cycloheptatriene and η-indene derivatives required two-dimensional (1H–1H) COSY and (13C–1H) correlation n.m.r. spectroscopy. Co-condensation of rhenium atoms with cyclohexane–trimethylphosphine gives [Re(η-C6H6)(PMe3)2H] where the η-benzene ligand derives from the cyclohexane.

Synthesis of η-arene rhenium compounds using rhenium atoms. Crystal structures of [Re2(η-C6H6)(η-C6H8)2(µ-H)2] and [Re(η-C6H6)(η-C6H8)H]

The reactions between the dimethyl sulphide complex [(π-C5H5)2Mo(SMe2)Br]+PF6– and some amines RR′CHNH2 under a variety of conditions have been studied. Aqueous amines RR′CHNH2, RR′= H2, MeH, Me2, HPrn, or MeEt, which have a β-C–H system, undergo oxidation giving the hydridoamines [(π-C5H5)2Mo(NH2CHRR′)H]+PF6– and the corresponding aldehydes or ketones RR′CO. Under anhydrous conditions the complexes [(π-C5H5)2Mo(NH2CHRR′)Br]+PF6– or [(π-C5H5)2Mo(NH2CHRR′)2]2+[PF6–]2 may be formed. The diammine [(π-C5H5)2Mo(NH3)2]2+[PF6–]2 has been prepared. The dimethyl sulphide complex in acetone reacts with ammonia giving the ketimine [(π-C5H5)2Mo(NHCMeR)NH3]2+[PF6–]2, R = Me; the analogue where R = Et has also been prepared. The mechanism of the amine oxidation is discussed. Further new complexes are described which include [(π-C5H5)2W(NH2Me)H]+PF6–, [(π-C5H5)2Mo(PMeH2)H]+PF6–, and [(π-C5H5)2Mo(PMeH2)Br]+PF6–.

Stoicheiometric, homogeneous oxidation of amines to aldehydes or ketones using bis-π-cyclopentadienyl molybdenum derivatives: ketimine molybdenum complexes

Malcolm L. H. Green

Papers

Synthesis of η-arene rhenium compounds using rhenium atoms. Crystal structures of [Re2(η-C6H6)(η-C6H8)2(µ-H)2] and [Re(η-C6H6)(η-C6H8)H]

Stoicheiometric, homogeneous oxidation of amines to aldehydes or ketones using bis-π-cyclopentadienyl molybdenum derivatives: ketimine molybdenum complexes

New cycloheptatriene and cycloheptatrienyl derivatives of niobium

Reductive dimerisation of but-2-yne on niobium: some chemistry of mono-η-cyclopentadienyl compounds

Single-Walled Carbon Nanotubes Filled with MOH (M: K, Cs) and Then Washed and Refilled with Clusters and Molecules.