Browsing by Author "Ng, MCC"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Central atom size effect on the structure of group 14 tetratolyls
    (Wiley-VCH Verlag Berlin, 2009-07-06) Ng, MCC; Craig, DJ; Harper, JB; van Eijck, L; Stride, JA
    Size matters! The structure and dynamics of the tetratolyl Group 14 elements, which were probed by using high-resolution inelastic neutron scattering spectra, show a remarkable dependence on the size of the central atom. The para-methyl groups at the periphery of the molecules constitute the frontier intermolecular interactions of increasingly larger tetrahedra, which becomes critical at the molecular radius of the Si and Ge analogues. © 2009, Wiley-VCH Verlag Berlin
  • No Thumbnail Available
    Item
    Central-atom size effects on the methyl torsions of group XIV tetratolyls
    (Wiley-V C H Verlag GMBH, 2012-10-01) Ng, MCC; Harper, JB; Stampfl, APJ; Kearley, GJ; Rols, S; Stride, JA
    The Group XIV tetratolyl series X(C6H4-CH3)4 (X=C, Si, Ge, Sn, Pb) were studied by using inelastic neutron scattering to measure the low-energy phonon spectra to directly access the methyl-group torsional modes. The effect of increased molecular radius as a function of the size of the central atom was shown to have direct influence on the methyl dynamics, reinforced with the findings of molecular dynamics and contact surface calculations, based upon the solid-state structures. The torsional modes in the lightest analogue were found to be predominantly intramolecular: the Si and Ge analogues have a high degree of intermolecular methylmethyl group interactions, whilst the heaviest analogues (Sn and Pb) showed pronounced intermolecular methyl interactions with the whole phonon bath of the lattice modes. © 2012, Wiley-VCH Verlag GmbH & Co. KGaA