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Central‐Atom Size Effects on the Methyl Torsions of Group XIV Tetratolyls
Author(s) -
Ng Maggie C. C.,
Harper Jason B.,
Stampfl Anton P. J.,
Kearley Gordon J.,
Rols Stéphane,
Stride John A.
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201202105
Subject(s) - intramolecular force , intermolecular force , methyl group , chemistry , inelastic neutron scattering , crystallography , atom (system on chip) , phonon , neutron scattering , molecular dynamics , molecule , scattering , group (periodic table) , computational chemistry , stereochemistry , physics , condensed matter physics , organic chemistry , computer science , optics , embedded system
The Group XIV tetratolyl series X(C 6 H 4 ‐CH 3 ) 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 methyl–methyl group interactions, whilst the heaviest analogues (Sn and Pb) showed pronounced intermolecular methyl interactions with the whole phonon bath of the lattice modes.