Showing papers by "Malcolm L. H. Green published in 2003"
TL;DR: A review of the main developments in the partial oxidation of methane to synthesis gas since the first paper in 1929 to the present day is given in this article, where the reaction is discussed from the view of the thermodynamics; the main catalysts studied for the reaction are summarised, and the reaction mechanism is discussed.
Abstract: A review of the main developments in the partial oxidation of methane to synthesis gas since the first paper in 1929 to the present day is given. The reaction is discussed from the view of the thermodynamics; the main catalysts studied for the reaction are summarised, and the reaction mechanism is discussed. The review is not comprehensive, but it is designed to provide a general background to the most important developments in the field.
471 citations
TL;DR: Control experiments and observations suggest that immobilization is strong, physical and does not require covalent bonding, and in terms of possible device applications, protein attachment appears to occur with retention of native biological structure.
Abstract: The nano dimensions, graphitic surface chemistry and electronic properties of single walled carbon nanotubes make such a material an ideal candidate for chemical or biochemical sensing. Carbon nanotubes can be nondestructively oxidized along their sidewalls or ends and subsequently covalently functionalized with colloidal particles or polyamine dendrimers via carboxylate chemistry. Proteins adsorb individually, strongly and noncovalently along nanotube lengths. These nanotube-protein conjugates are readily characterized at the molecular level by atomic force microscopy. Several metalloproteins and enzymes have been bound on both the sidewalls and termini of single walled carbon nanotubes. Though coupling can be controlled, to a degree, through variation of tube oxidative pre-activation chemistry, careful control experiments and observations made by atomic force microscopy suggest that immobilization is strong, physical and does not require covalent bonding. Importantly, in terms of possible device applications, protein attachment appears to occur with retention of native biological structure. Nanotube electrodes exhibit useful voltammetric properties with direct electrical communication possible between a redox-active biomolecule and the delocalized pi system of its carbon nanotube support.
262 citations
TL;DR: Single-walled carbon nanotubes have been cyclopropanated under Bingel reaction conditions, and the functionalized nanot tubes have been characterized by atomic force microscopy using "chemical tagging" techniques.
Abstract: Single-walled carbon nanotubes have been cyclopropanated under Bingel reaction conditions, and the functionalized nanotubes have been characterized by atomic force microscopy using "chemical tagging" techniques.
242 citations
TL;DR: In this article, a series of WO4 tetrahedron on the surface of trimetallic catalysts was studied and their catalytic performance for the oxidative coupling of methane (OCM) was evaluated in a continuous flow microreactor.
151 citations
TL;DR: The detailed crystallography is described of an entire helical one-dimensional cobalt diiodide nanostructure encapsulated within a SWNT that has an unprecedented twisted double tetrahedral chain structure arising from a rotation of Co2I4 units along its length.
Abstract: Single-walled carbon nanotubes (SWNTs) can be used as templates for the growth of low-dimensional inorganic materials whose structures and properties often differ greatly from those of the bulk. Here we describe the detailed crystallography of an entire helical one-dimensional cobalt diiodide nanostructure encapsulated within a SWNT. This material has an unprecedented twisted double tetrahedral chain structure arising from a rotation of Co(2)I(4) units along its length. The complete nanostructure comprises two distinct regions with oppositely handed helices separated by a short disordered region. The encapsulating SWNT shows a commensurate ovoid distortion reflecting an unexpectedly strong interaction between the nanostructure and the SWNT.
151 citations
TL;DR: Sloan et al. as mentioned in this paper compared the properties of simple binary halides formed by the alkali iodides MI (M = Li, K, Na, Rb and Cs) within single walled carbon nanotubes (SWNTs).
84 citations
TL;DR: A new imino-N-heterocyclic carbene ligand precursor [1-(2,4,6-Me3C6H2)imidazolium-3-{CH2C(t-Bu)N(i-Pr)}] bromide has been synthesised and structurally characterised.
Abstract: A new imino-N-heterocyclic carbene ligand precursor [1-(2,4,6-Me3C6H2)imidazolium-3-{CH2C(t-Bu)N(i-Pr)}] bromide has been synthesised and structurally characterised. The silver(I) complex [Ag(C⁁imine)2]AgBr2, where (C⁁imine)
= 1-(2,4,6-Me3C6H2)imidazol-2-ylidene-3-{CH2C(t-Bu)N(i-Pr)}, was readily prepared by reaction with Ag2O. Transfer of the ligand from silver(I) to palladium(II) and rhodium(I) by reaction with [PdCl2(MeCN)2] and [Rh(cod)(THF)2][BF4] led to the tautomerisation of the imine moiety to the enamine affording the structurally characterised complex [PdCl2(C⁁enamine)] and [Rh(cod)(C⁁enamine)][BF4] respectively, where (C⁁enamine)
= 1-(2,4,6-Me3C6H2)imidazol-2-ylidene-3-{CHC(t-Bu)NH(i-Pr)}.
79 citations
TL;DR: In this paper, the authors describe the high yield filling of single walled nanotubes (SWNTs) with a variety of halides, achieved according to various modified filling procedures.
Abstract: We describe here the high yield filling (i.e. >50%) of single walled nanotubes (SWNTs) with a variety of halides, achieved according to various modified filling procedures. Both bundles and discrete SWNTs can be filled continuously up to lengths of several hundred nm, often with filling yields approaching 60–70% or better. In addition some high yield filled SWNTs were subjected to long-term washing in either boiling or room temperature. aqueous media, which does not remove the filling from the tubules, but enables effective removal of water-soluble extraneous materials .
64 citations
TL;DR: The new compounds [K(18crown-6)][SCNB(C6F5)3] and [Hg{(μ-CN)B(C5H5)(CO)2CN] have been synthesized.
Abstract: The new compounds [K(18-crown-6)][SCNB(C6F5)3]
(1), [K(18-crown-6)][(C6F5)3B(μ-NC)B(C6F5)3]
(2), [K(18-crown-6)][NCB(C6F5)3]
(3), [Me3Si(μ-NC)B(C6F5)3]
(4) and [Hg{(μ-CN)B(C6F5)3}2]
(5) have been synthesised. Reaction between [IrCl(PPh3)2(CO)] and one equivalent of 4 gives [Ir{(μ-NC)B(C6F5)3}(PPh3)2CO]
(6). Similarly, the reaction between [Fe(η-C5H5)(CO)2Cl] and 4 gives [Fe{(μ-NC)B(C6F5)3}(η-C5H5)(CO)2]
(7a). The NMR-scale reaction between [Fe(η-C5H5)(CO)2CN] and B(C6F5)3 gives the isomer [Fe{(μ-CN)B(C6F5)3}(η-C5H5)(CO)2]
(7b). In the compounds 3, 4, 6 and 7a the anion [NCB(C6F5)3]− is coordinated to the metal through the nitrogen. Complexes 1, 2 and 7b incorporate a (μ-CN)B unit. The compounds containing the isomeric bridging (μ-CN)B or (μ-NC)B systems have been investigated by 11B{1H} NMR spectroscopy and by DFT calculations. The 11B{1H} NMR spectra enable distinction between the isomers. The single-crystal X-ray structures of 1, 3 and 7a have been determined.
54 citations
TL;DR: An approach to the unambiguous determination of the conformation of individual single walled nanotubes utilizing high‐resolution transmission electron microscopy and digital image processing and a combination of these complementary characterization steps yields an accurate measurement of the chiral vector for an individual nanotube.
Abstract: An approach to the unambiguous determination of the conformation of individual single walled nanotubes utilizing high-resolution transmission electron microscopy and digital image processing is described. The exit plane wave of single walled nanotubes restored from a focal series of images is used in a stepwise characterization procedure utilizing both the phase of the real space restoration and its Fourier transform. A combination of these complementary characterization steps yields an accurate measurement of the chiral vector for an individual nanotube.
45 citations
TL;DR: In this article, the role of these n-alkyl complexes in the controlled polymerization of styrene is discussed, where the authors show that there is an agostic interaction of the nalkyl groups' β-CH_2 hydrogen atoms with the formally 12-electron lanthanide metal center.
TL;DR: In this paper, a series of molybdenum modified alumina supported nickel catalysts have been prepared and tested for methane dry reforming to synthesis gas, and they have been shown to have a greater stability than when CO2/CH4 ratio = 1.
Abstract: A series of molybdenum modified alumina supported nickel catalysts have been prepared and tested for methane dry reforming to synthesis gas. The molybdenum additive reduces carbon deposition in the catalyst, and lowers the catalyst activity and selectivity. Increase of the amount of molybdenum additive causes a more rapid decrease in catalyst activity. Using a feedstock of CO2/CH4 ratio=1, the molybdenum-doped nickel catalyst has a greater stability than when CO2/CH4=1.1. Carburisation pretreatment of the molybdenum modified nickel catalyst using 20 vol.% CH4/H2 leads to a small improvement in catalyst stability. The formation of NiMoO4 is believed to be responsible for the decrease of catalyst activity.
TL;DR: In this paper, a single walled carbon nanotubes is characterized at the molecular level by atomic force microscopy and shown to have strong, physical and does not require covalent bonding.
Abstract: The nano dimensions, graphitic surface chemistry and electronic properties of single walled carbon nanotubes make such a material an ideal candidate for chemical or biochemical sensing. Carbon nanotubes can be nondestructively oxidized along their sidewalls or ends and subsequently covalently functionalized with colloidal particles or polyamine dendrimers via carboxylate chemistry. Proteins adsorb individually, strongly and noncovalently along nanotube lengths. These nanotube-protein conjugates are readily characterized at the molecular level by atomic force microscopy. Several metalloproteins and enzymes have been bound on both the sidewalls and termini of single walled carbon nanotubes. Though coupling can be controlled, to a degree, through variation of tube oxidative pre-activation chemistry, careful control experiments and observations made by atomic force microscopy suggest that immobilization is strong, physical and does not require covalent bonding. Importantly, in terms of possible device applications, protein attachment appears to occur with retention of native biological structure. Nanotube electrodes exhibit useful voltammetric properties with direct electrical communication possible between a redox-active biomolecule and the delocalized pi system of its carbon nanotube support.
TL;DR: In this paper, the reactions of P,O type ligands with half-sandwich complexes (R5, Me5, iPrH4, Nb, Ta, W) have been investigated.
Abstract: The reactions of P,O type ligands with the half-sandwich complexes [(η-C5R5)MCl4]
(R5 = H5, Me5, iPrH4; M = Nb, Ta, W) have been investigated. Monodentate P-adducts were obtained with the β-amidophosphine Ph2PCH2C(O)NPh2, whereas in the case of the keto ligand Ph2PCH2C(O)Ph a spontaneous HCl elimination occurred to give direct access to the corresponding phosphinoenolate complexes. The crystal structures of [(η-C5H5)NbCl3{PPh2CHC(O)Ph}], [(η-C5H5)TaCl3{PPh2CHC(O)Ph}] and [(η-C5Me5)TaCl3{PPh2CHC(O)Ph}] have been determined. Interestingly, the acetamido derived phosphine Ph2PNHC(O)Me afforded O-adducts, which is an unusual bonding mode for a P,O ligand.
TL;DR: Ordered 1D crystals of a complex pentlandite-type alloy with the general composition (Fe,Ni,Co)9S8 have been synthesised inside conical Multi Walled Carbon Nanotubes (MWNTs); the crystals are observed as a by-product of an arc-evaporation synthesis of Double Walled carbon Nanot tubes (DWNTs).