Molecular conformation and methyl proton delocalization in triiodomesitylene: A combined density functional theory and single-crystal neutron diffraction study

摘要: First the conformations of various ortho and di-ortho substituted toluenes calculated by quantum chemistry methods are discussed as well hindering potentials deduced from latter results those established experimentally microwaves fluorescence techniques. It appears that methyl (Me) groups much less hindered in than compounds. Then study 1,3,5-triiodo-2,4,6-trimethylbenzene (triiodomesitylene or TIM) is reported. Density functional theory (DFT) calculations indicate two TIM molecule have same formation energies. One has C3h symmetry, other with Cs symmetry obtained a rotation 60° for one Me. Experimentally, structure been determined at 15 K using single-crystal neutron diffraction data. crystallizes triclinic space group P−1. Molecules stacked an antiferroelectric manner along oblique axis. For Me experimental conformation close...