We have performed high-resolution inelastic neutron scattering studies on three samples of hydrogenated tetrahydrofuran-water clathrates, containing either H2 at different para/ortho concentrtion, or HD. By a refined analysis of the data, we are able to assign the spectral bands to rotational and center-of-mass translational transitions of either para- or ortho-H2. The H2 molecule rotates almost freely, while performing a translational motion (rattling) in the nanometric-size cage, resulting a paradigmatic example of quantum dynamics in a non-harmonic potential well. Both the H2 rotational transition and the fundamental of the rattling transition split into triplets, having different separation. The splitting is a consequence of a substantial anisotropy of the environment with respect to the orientation of the molecule in the cage, in the first case, or with respect to the center-of-mass position inside the cage, in the second case. The values of the transition frequencies and band intensities have been quantitatively related to the details of the interaction potential between H2 and the water molecules, with a very good agreement

The Raman spectrum of hydrogen clathrate hydrates has been measured, as a function of temperature, down to 20 K. Rotational bands of H(2) and HD, trapped into the small cages of simple (H(2)O-H(2)) and binary (H(2)O-THF-H(2)) hydrates, have been analyzed and the fivefold degeneracy of the molecular J=2 rotational level has been discussed in the light of the available theoretical calculations. The vibrational frequencies of H(2) molecules encapsulated in the large cages of simple hydrates turn out to be well separated from those pertaining to the small cages. Comparison with the equivalent D(2) spectra allowed us to assign the large cavity vibrational frequencies to three couples of Q(1)(1)-Q(1)(0) H(2) vibrational modes. Populations of ortho and para species have been measured as a function of time from rotational spectra and the rate of ortho-para conversion has been estimated for both simple and binary hydrates. We suggest, using the H(2) vibrational spectra, a model to analyze the cage population in simple hydrates.

An efficient approach to the organic functionalization of multiwalled carbon nanotubes (MWCNTs) for the production of highly soluble/dispersible materials has been accomplished by a class of highly reactive and thermally stable nitrones. Besides the unprecedented solubility in aprotic polar solvents of the functionalized samples (up to 10 mg of f-MWCNTs per mL of DMF), we have demonstrated, for the first time, that the CNT functionalization by nitrones preferentially occurs at the defective CNT sidewalls without any appreciable degradation of their sp2 network. The role of the reticular imperfections on the graphitic lattice of the MWCNTs has been experimentally and theoretically addressed. A complete chemical (TGA-MS, FT-IR, SSA) and morphological (TEM, AFM) characterization of the functionalized materials has accounted for the high degree of CNT functionalization, whereas Raman scattering, in combination with complementary XRPD and active surface area (ASA) measurements, has provided unambiguous evidence of the key role played by the structural “disorder” of the MWCNTs in the nitrone cycloaddition. Density functional theory (DFT) calculations on the reactivity of selected topological defects at the CNT sidewalls have contributed to trace-out a “defect-based” sidewall reactivity trend. The excellent processability of the functionalized MWCNTs has been finally exploited for the preparation of highly homogeneous CNT/polymer nanocomposites with CNT loadings as high as 3 wt%

Raman spectra of Mg(BH(4))(2) have been measured in an extensive temperature range, from 15 to 473 K. Taking into account the high temperature conversion from the alpha to the beta phase, we have observed evident signatures of this phase transition and determined the Raman vibrational spectrum of each phase. The neutron scattering spectra of the beta phase sample were also recorded. The present experimental results have been compared to the density functional theory calculations available in the literature, and a substantial agreement has been found.

An unprecedented functionalization of multi-walled carbon nanotubes (MWCNTs) has been conveniently achieved by the 1,3-dipolar cycloaddition of a cyclic nitrone. This organic functionalization yields materials with a great solubility in DMF (close to 10 mg per mL of DMF) preferentially occurring at the defects of the MWCNT sp(2) network.