ORCID Profile
0000-0001-7738-4098
Current Organisation
University of Nottingham
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Publisher: The Royal Society
Date: 15-07-2003
Abstract: Most experts agree that it is too early to say how quantum computers will eventually be built, and several nanoscale solid-state schemes are being implemented in a range of materials. Nanofabricated quantum dots can be made in designer configurations, with established technology for controlling interactions and for reading out results. Epitaxial quantum dots can be grown in vertical arrays in semiconductors, and ultrafast optical techniques are available for controlling and measuring their excitations. Single-walled carbon nanotubes can be used for molecular self-assembly of endohedral fullerenes, which can embody quantum information in the electron spin. The challenges of in idual addressing in such tiny structures could rapidly become intractable with increasing numbers of qubits, but these schemes are amenable to global addressing methods for computation.
Publisher: Wiley
Date: 27-10-2013
Abstract: By exposing flat and curved carbon surfaces to coronene, a variety of van der Waals hybrid heterostructures are prepared, including coronene encapsulated in carbon nanotubes, and coronene and dicoronylene adsorbed on nanotubes or graphite via π-π interactions. The structure of the final product is determined by the temperature of the experiment and the curvature of the carbon surface. While at temperatures below and close to the sublimation point of coronene, nanotubes with suitable diameters are filled with single coronene molecules, at higher temperatures additional dimerization and oligomerization of coronene occurs on the surface of carbon nanotubes. The fact that dicoronylene and possible higher oligomers are formed at lower temperatures than expected for vapor-phase polymerization indicates the active role of the carbon surface used primarily as template. Removal of adsorbed species from the nanotube surface is of utmost importance for reliable characterization of encapsulated molecules: it is demonstrated that the green fluorescence attributed previously to encapsulated coronene is instead caused by dicoronylene adsorbed on the surface which can be solubilized and removed using surfactants. After removing most of the adsorbed layer, a combination of Raman spectroscopy and transmission electron microscopy was employed to follow the transformation dynamics of coronene molecules inside nanotubes.
Publisher: Informa UK Limited
Date: 08-2004
Publisher: American Chemical Society (ACS)
Date: 09-12-2011
DOI: 10.1021/JA207845U
Abstract: Reaction of H(3)L with Cd(NO(3))(2)·4H(2)O in DMF at 150 °C for 3 days affords the metal-organic nanosphere [Cd(66)(μ(3)-OH)(28)(μ(3)-O)(16)(μ(5)-NO(3)-O,O,O',O',O″,O″)(12)(L)(20)(μ(2)-DMF)(12)⊂(DMF)(9)]. The cluster is composed of a spherical shell of 66 Cd(II) cations bridged by 28 μ(3)-hydroxide, 16 μ(3)-oxo, and five μ(5)-NO(3)(-) anions surrounded by a shell of 20 tripodal capping ligands (L) and 12 DMF ligands. The 66 Cd(II) cations and 12 NO(3)(-) anions form a polydeltahedron that has 78 vertices [Cd(II) or NO(3)(-)] (V), 228 edges (E), and 152 triangular faces (F), giving it an Euler characteristic (χ) of 2 (χ = V + F - E). Reaction of H(3)L with Cd(NO(3))(2)·4H(2)O at lower temperatures or with CdCl(2) affords coordination polymer frameworks instead of nanospheres.
Publisher: Wiley
Date: 02-03-2004
Publisher: American Chemical Society (ACS)
Date: 12-10-2022
Publisher: American Chemical Society (ACS)
Date: 10-05-2003
DOI: 10.1021/JA029048Y
Abstract: A series of structurally related binuclear metallacycles [Cd(NO(3))(2)L](2), where L is an angular exo-bidentate ligand, have been synthesized. Each metallacycle contains two coordinatively unsaturated, chiral metal centers within a single molecule, and the assembly of these metallacycles into polymeric framework structures has been studied systematically for the first time. Stereoselective homochiral association of [Cd(NO(3))(2)L](2) leads to the formation of helical coordination polymers, whereas meso type association results in nonhelical chain structures. The type of stereoselective aggregation depends on the conditions of self-assembly as well as on ligand functionality. Both helical and nonhelical polymeric complexes have been isolated for the metallacycle [Cd(NO(3))(2)(2,4'-pyacph)](2) (2,4'-pyacph = 2,4'-(4-ethynylphenyl)bipyridyl). Homochiral association results in the formation of helical [Cd(NO(3))]( infinity ) chains which link the binuclear [Cd(NO(3))(2)(2,4'-pyacph)](2) metallacycles into racemic two-dimensional sheets which contain both P and M [Cd(NO(3))]( infinity ) helices. In contrast, meso-association leads to the formation of nonhelical one-dimensional chains. It is shown that the product of homochiral association is predominately formed at room temperature and that of meso-association is generated at elevated temperatures. Thus, it may be concluded that the homochiral association appears to be energetically less favorable than the meso-association, a conclusion that has been confirmed by theoretical calculations of the crystal lattice energy. Several high-yield syntheses of bipyridyl-type ligands used for metallacyclic assembly are also reported.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CC08029G
Abstract: Carbon nanotube encapsulation offers a mechanism to trap kinetically rather than thermodynamically favoured supramolecular arrays.
Publisher: IOP Publishing
Date: 29-06-2023
Abstract: Integration of graphene and hexagonal boron nitride (hBN) in lateral heterostructures has provided a route to broadly engineer the material properties by quantum confinement of electrons or introduction of novel electronic and magnetic states at the interface. In this work we demonstrate lateral heteroepitaxial growth of graphene nanoribbons (GNRs) passivated by hBN using high-temperature molecular beam epitaxy (HT-MBE) to grow graphene in oriented hBN trenches formed ex-situ by catalytic nanoparticle etching. High-resolution atomic force microscopy (AFM) reveals that GNRs grow epitaxially from the etched hBN edges, and merge to form a GNR network passivated by hBN. Using conductive AFM we probe the nanoscale electrical properties of the nanoribbons and observe quasiparticle interference patterns caused by intervalley scattering at the graphene/hBN interface, which carries implications for the potential transport characteristics of hBN passivated GNR devices.
Publisher: Wiley
Date: 09-2009
Abstract: The solution properties of a series of transition-metal-ligand coordination polymers [ML(X)(n)](infinity) [M=Ag(I), Zn(II), Hg(II) and Cd(II) L=4,4'-bipyridine (4,4'-bipy), pyrazine (pyz), 3,4'-bipyridine (3,4'-bipy), 4-(10-(pyridin-4-yl)anthracen-9-yl)pyridine (anbp) X=NO(3) (-), CH(3)COO(-), CF(3)SO(3) (-), Cl(-), BF(4) (-) n=1 or 2] in the presence of competing anions, metal cations and ligands have been investigated systematically. Providing that the solubility of the starting complex is sufficiently high, all the components of the coordination polymer, namely the anion, the cation and the ligand, can be exchanged on contact with a solution phase of a competing component. The solubility of coordination polymers is a key factor in the analysis of their reactivity and this solubility depends strongly on the physical properties of the solvent and on its ability to bind metal cations constituting the backbone of the coordination polymer. The degree of reversibility of these solvent-induced anion-exchange transformations is determined by the ratio of the solubility product constants for the starting and resultant complexes, which in turn depend upon the choice of solvent and the temperature. The extent of anion exchange is controlled effectively by the ratio of the concentrations of incoming ions to outgoing ions in the liquid phase and the solvation of various constituent components comprising the coordination polymer. These observations can be rationalised in terms of a dynamic equilibrium of ion exchange reactions coupled with Ostwald ripening of crystalline products. The single-crystal X-ray structures of [Ag(pyz)ClO(4)](infinity) (1), {[Ag(4,4'-bipy)(CF(3)SO(3))]CH(3)CN}(infinity) (2), {[Ag(4,4'-bipy)(CH(3)CN)]ClO(4) 0.5 CH(3)CN}(infinity) (3), metal-free anbp (4), [Ag(anbp)NO(3)(H(2)O)](infinity) (5), {[Cd(4,4'-bipy)(2)(H(2)O)(2)](NO(3))(2)4 H(2)O}(infinity) (6) and {[Zn(4,4'-bipy)SO(4)(H(2)O)(3)] 2 H(2)O}(infinity) (7) are reported.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3NA00155E
Abstract: Non-integrated correlative light-electron microscopy with nitrogen vacancy sensing on transmission electron microscopy finder grids for the study of paramagnetic Prussian blue analogue nanoparticles.
Publisher: Wiley
Date: 17-09-2010
Abstract: For carbon nanotubes filled with fullerenes (“peapods”), it is a key issue to find an analytical method that distinguishes the molecules inside the nanotube from those adsorbed on its surface. High‐resolution transmission electron microscopy (HRTEM) detects both encapsulated and adsorbed molecules which are large enough ( e.g ., fullerenes), but being a local‐probe method, it cannot be applied to large amounts of s le. In Raman spectroscopy, the empirical rules for line shifts and splitting are nanotube‐type dependent and often ambiguous. We prepared C 60 peapods by nano‐extraction using supercritical CO 2 as a solvent, and subsequently removed the adsorbed fullerene molecules by washing the s les. We analyzed the s les by the combination of HRTEM, Raman, and midinfrared attenuated total reflectance (MIR‐ATR) spectroscopy. Although the TEM images proved that the nanotubes were filled with fullerenes, we did not observe any shift in the fullerene's A g (2) Raman mode compared to C 60 crystals. ATR spectra, on the other hand, were found to detect only the adsorbed molecules. Therefore, the combination of the two methods provide good basis for determining the success of nanotube filling by spectroscopy alone.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Andrei Khlobystov.