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Using the first realistic model of single walled carbon nanohorn and molecular simulation data we show the 3D graphs relating the selectivity of CO2/CH4 separation with a surface to volume ratio of a nanohorn, the total mixture pressure and the mole fraction of CO2 in the bulk phase. It is proved that surface to volume ratio is a crucial parameter determining the selectivity. Finally, the equation is proposed, making possible to predict the selectivity of a nanohorn for separation of CO2/CH4 mixture.

We introduce a way to selectively probe local vibration modes at nanostructured asperities such as tips of carbon nanohorns. Our observations benefit from signal amplification in surface-enhanced Raman scattering (SERS) at sites near a silver surface. We observe nanohorn tip vibration modes in the range 200?500 cm?1, which are obscured in regular Raman spectra. Ab initio density functional calculations assign modes in this frequency range to local vibrations at the nanohorn cap resembling the radial breathing mode of fullerenes. Careful interpretation of our SERS spectra indicates presence of caps with 5 or 6 pentagons, which are chemically the most active sites. Changes in the peak intensities and frequencies with time indicate that exposure to laser irradiation may cause structural rearrangements at the cap., The Journal of Chemical Physics, 136(6), 064505; 2012

The quasi-Werner-type copper(II) complex, [Cu(PF6)2(4-mepy)4] (1), in which 4-mepy is the 4-methylpyridine ligand, has flexible and polar axial bonds of Cu-PF6. Flexibility of the Cu-PF6 bonds induces diverse and unprecedented guest-inclusion structures, such as {[Cu(PF6)2(4-mepy)4][Cu(PF6)(4-mepy)4(acetone)]・PF6・4acetone} (γ-1⊃2.5acetone), {[Cu(PF6)2(4-mepy)4][Cu(PF6)(4-mepy)4(2-butanone)]・PF6・3.5(2-butanone)} (γ-1⊃2.25(2-butanone)), {[Cu(PF6)2(4-mepy)4][Cu(PF6)(4-mepy)4(H2O)]・PF6・4benzene} (γ-1⊃0.5H2O・2benzene), and {[Cu(PF6)2(4-mepy)4]・2benzene} (γ-1⊃2benzene). Exposure of the dense form, α-1, to benzene vapor affords the benzene-inclusion complex {[Cu(PF6)2(4-mepy)4]・2benzene} (γ-1⊃2benzene), all benzene guests of which are easily removed by vacuum drying, reforming guest-free, dense α-1' with smaller sized crystals than α-1. In contrast to α-1, which shows almost no CO2 adsorption, α-1' adsorbs CO2 gas with structural transformations, this being the first example that exhibits adsorption of gas in a dense Werner-type complex and a drastic change in adsorption properties depending on the size of the crystals.