Malcolm L. H. Green

Bio: Malcolm L. H. Green is an academic researcher from University of Oxford. The author has contributed to research in topics: Carbon nanotube & Cyclopentadienyl complex. The author has an hindex of 82, co-authored 800 publications receiving 31121 citations. Previous affiliations of Malcolm L. H. Green include Gas Technology Institute & University of Illinois at Urbana–Champaign.

Zirconocenes as Photoinitiators for Free-Radical Polymerisation of Acrylates

Abstract: This paper reports the photochemical behaviour of unbridged (1−6) and bridged zirconocenes (7r, 7m), whose substituents differ in both electron-donor and steric properties. The study of the electronic spectra and EPR spin-trapping experiments showed the photogeneration of ligand- and zirconium-centred radicals at wavelengths higher than 350 nm. This feature makes these complexes suitable as photoinitiators for radical polymerisation processes. tert-Butyl acrylate polymerisation has been studied in detail and the results are particularly encouraging as far as the reaction yields and the stereochemistry are concerned. In particular, the complexes 4−6, due to the tuneability of their structure and their stability in solution, look the most promising reagents.

Structure and dynamics of cobaltocene intercalated in tantalum disulphide investigated by 2H n.m.r. spectroscopy

Abstract: 2 H N.m.r. spectroscopy reveals the existence of two orientations of the cobaltocenium ion in the [Co(η-C5H5)2]1/4TaS2 intercalate, with different dynamic properties in each orientation.

Group 6 transition metal carbonyl complexes with chalcogen-bridged diarsenic(III) ligands

Abstract: The neutral complexes [Cr(CO)4(Ph2AsOAsPh2)] 1, [Mo(CO)4(Ph2AsOAsPh2)2] 2, [Cr(CO)4(Ph2AsSAsPh2)] 3, [Mo(CO)4(Ph2AsSAsPh2)2] 4, [Cr(CO)5(Ph2AsOAsPh2)] 5 and [Cr(CO)5(Ph2AsSAsPh2)] 6 have been prepared. The crystal structures of compounds 1–5 were determined. The diarsenic ligand in 2, 4, and 5 is monodentate and in 1 and 3 the ligand is bidentate. The crystal structure of the ligand Ph2AsOAsPh2 was redetermined and the As–O–As angle found to be 115.98(17)°, significantly less than the value originally reported. Calculations, using density functional theory, assist discussion of the steric and electronic factors influencing the choice of binding mode.

η-1,2,4,6-tetramethylcycloheptatrienyl molybdenum chemistry

Abstract: Treatment of [Mo(CO)6] with 1,3,5,7-tetramethylcycloheptatriene in octane gives a mixture of [Mo(η6-C7H4Me4-1,3,5,7)(CO)3]1, [Mo(η6-C7H4Me4-1,2,4,6)(CO)3]2 and [Mo(η6-C7H4Me4-1,3,4,6)(CO)3]3. The compounds 2 and 3 arise as a result of sequential 1,5-shifts of the 7-endo-hydrogen atom of the initially formed 1. Hydride abstraction from compounds 1–3 by [CPh3][BF4] gives [Mo(η7-C7H3Me4-1,2,4,6)(CO)3][BF4]4. Compound 4 reacts with LiCl to yield [Mo(η7-C7H3Me4-1,2,4,6)(CO)2Cl]5 which reacts with 1 equivalent of Me2PCH2CH2PMe2(dmpe) to give [Mo(η3-C7H3Me4-1,2,4,6)(dmpe)(CO)2Cl]7. This is fluxional due to trigonal twist rearrangement and 1,2-shift of metal around the C7 ring. Photolysis of 7 in toluene produces [Mo(η7-C7H3Me4-1,2,4,6)(dmpe)Cl]9. Treatment of 4 with toluene affords the mixed-sandwich compound [Mo(η6-C6H5Me)(η7-C7H3Me4-1,2,4,6)][BF4]10 which yields [Mo(η7-C7H3Me4-1,2,4,6)(CH3COCHCOCH3)(PPh3)]11 upon treatment with sodium pentane-2,4-dionate and triphenylphosphine.

Encapsulation and crystallization behavior of materials inside carbon nanotubes

Abstract: Publisher Summary This chapter focuses on methods of opening, filling, and purifying multiple and single-walled carbon nanotubes. The multiple-walled carbon nanotubes (MWTs) can be prepared in the bulk by a modified Kratschmer–Huffmann procedure. MWTs are prepared from 1-cm-diameter graphite rods under ∼0.17 atm of helium and from an arc generated by a dc voltage of 30 V and a current of ∼180 A. The MWTs are formed in the carbon distilled on the cathode as a soft deposit covered by a hard cylindrical outer layer. The MWTs can then be removed from the soft inner core of the deposit and the outer shell is discarded. The nature of the products in the distillate obtained by this method can be radically altered by the introduction of additives to the source carbon electrode. Single-walled carbon nanotubes (SWTs) can be synthesized by coevaporating composite carbon rods mixed with certain metals, as in a modified Kratschmer–Huffmann-type experiment, and by laser vaporization of metal-doped graphite targets. Most techniques of SWT purification involve a method of isolating the undesired extraneous materials followed by some process of selective filtration.

Single-shell carbon nanotubes of 1-nm diameter

Abstract: 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.

Chemistry and properties of nanocrystals of different shapes.

Abstract: 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

Carbon Nanotubes: Present and Future Commercial Applications

Abstract: 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.

Nanoparticle therapeutics: an emerging treatment modality for cancer

Abstract: 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.

Chemistry of Carbon Nanotubes

Abstract: 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