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Graphite is exfoliated into graphene by shearing vortex fluidic films of N-methyl-pyrrolidone (NMP), as a controlled process for preparing oxide free graphene, and for exfoliating the corresponding boron nitride sheets. 相似文献
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Anantachoke N Makha M Raston CL Reutrakul V Smith NC Saunders M 《Journal of the American Chemical Society》2006,128(42):13847-13853
Nanoparticles of trans-beta-carotene are accessible using spinning disk processing (SDP), by varying the reaction conditions and the choice of surfactant, macrocyclic amphiphiles, sulfonato-calix[4,5,6,8]arenes, and alpha,beta-cyclodextrins. SDP ensures rapid mixing and fast kinetics, and nanoparticles of the carotene formed in the presence of the calixarenes are stable with respect to extraction of the carotene into an organic solvent, unlike in the presence of the cyclodextrins. Insight into the supramolecular structure of the carotene nanoparticles has also been established. The mean particle sizes (dynamic light scattering, DLS) have been optimized at 40(2) and 56(1) nm and 71.4(6) and 82(1) nm, respectively, for each sulfonato-calix[5,6 and 4,8]arene, whereas the cyclodextrins form nanoparticles with a mean diameter of 71(1) and 68.5(6) nm, respectively. Zeta-potential studies show stability of all the colloidal dispersions at pH > 4 with values below -30 mV. UV-visible spectroscopy shows a blue shift indicative of H-aggregates of the carotene within the nanoparticles. The surface area derived from BET studies is 39.12 m(2)/g corresponding to particles of 76.7(5) nm in diameter, in agreement with sizes obtained from DLS and TEM measurements. 相似文献
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Petrella AJ Roberts NK Craig DC Raston CL Lamb RN 《Chemical communications (Cambridge, England)》2003,(8):1014-1015
Reaction of p-'Bu-calix[6]arene with potassium metal in methanol followed by [TiCp2Cl2] affords novel mononuclear and binuclear monocyclopentadienyl titanium(IV) complexes, both having the same inverted double cone conformation with a Cp in one of the cavities, in both complexes. 相似文献
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Paul L. Raston 《Journal of Molecular Spectroscopy》2007,244(2):138-145
We report high resolution infrared absorption studies of rare gas (Rg) atom doped solid parahydrogen in the hydrogen S1(0) region around 4486 cm−1. At low Rg atom concentrations (∼0.1%), satellite transitions appear in the S1(0) region due to rovibrational excitation of parahydrogen molecules with one nearest-neighbor Rg atom. The Ne satellite feature differs qualitatively from the Ar, Kr, and Xe satellite features for reasons described within. The frequency of the S1(0) satellite features linearly shift to lower energy as the polarizability of the Rg atom increases while the absorption coefficients increase with the square of the Rg atom polarizability. Rotational calculations are performed for H2 with a nearest-neighbor Rg atom assuming a rigid hexagonal close-packed lattice structure. The calculated fine structure of the S1(0) satellite features agree qualitatively with lifting of the 2J+1 degeneracy of the v = 1, J = 2 upper state caused by the anisotropy in the Rg-H2 intermolecular potential. The discrepancy between the calculated and measured Rg atom S1(0) satellite features may signal partial delocalization of the J = 2 roton onto neighboring parahydrogen molecules. 相似文献
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Kevin D. Croft Emilio L. Ghisalberti Philip R. Jefferies Colin L. Raston Allan H. White Sydney R. Hall 《Tetrahedron》1977,33(12):1475-1480
The structure of the title compound has been shown to be (6), a diterpenoid analogue of the cadinene group. Standard degradation has given the naphthalene (14). The relative stereochemistry is established by crystal structure of dihydroxyserrulatic acid which has been determined by X-ray diffraction at 295 K, and refined by least squares to a residual of 0.059 for 1480 observed reflections. Crystals are orthorhombic, P 212121, a = 15.514 (3), b=14.029 (3), c=8.681 (2)Å, Z=4. 相似文献
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Bowl-shaped C-methylcalix[4]resorcinarene forms a 1:1 ball-and-socket nanostructure with o-carborane through two endo-cavity BC-H...pi hydrogen bonds. In the presence of 4',2:6,4"-terpyridine, two of these nanostructures are held together by four terpyridines through sixteen OH...N hydrogen bonds, completely shrouding two carboranes. 相似文献