1,2-Di-tert-butyltetrafluorodisilane: A Highly Fluxional Molecule

Hassler K, Mitzel NW, Smart BA, Rankin DWH. 1,2-Di-tert-butyltetrafluorodisilane: A Highly Fluxional Molecule. Organosilicon Chemistry III, Wiley VCH. 1998:248-253

The molecular structure of pentaborane(9) with halogen substituents in apical and basal positions, determined by electron diffraction and theoretical calculations

The molecular structures of 1-bromo–pentaborane(9) and 2-bromo–pentaborane(9) in the gas phase have been determined by electron diffraction and ab initio and DFT computational methods. Computational methods have also been applied to the fluoro and chloro analogues, to 1,2-dibromo-pentaborane(9), and to the parent unsubstituted borane. The electronic effects of halogen substitution on the borane cage are remarkably small, particularly for chlorine and bromine substituents, and steric effects are also minimal, even in the compound with two bromine atoms. The largest effects are (a) lengthening of B(base)–B(apex) bonds adjacent to the halogen in the 2-isomers, with an associated shortening of the opposite base–apex bond, (b) shortening of the B(base)–B(apex) bond in the 1-fluoro compound, and (c) increase of the B(base)–B(apex)–F angle in 1-F–B5H8, but a decrease in this angle in the 2-bromo compounds

Molecular structure of ru(eta-C5Me5)(eta-C5F5) by gas-phase electron diffraction and density functional theory

The structure of Ru(C5Me5)(C5F5) has been determined by gas-phase electron diffraction and density functional theory. Comparison structures of the known compounds Ru(C5H5)2 and Ru(C5F5)(C5H5), as well as the unknown compound Ru(C5F5)2, have also been determined by density functional theory

Unusual asymmetry in halobenzenes, a solid-state, gas-phase and theoretical investigation

The molecular structures of 1-Br-4-F-C 6H 4 and 1-Cl-4-F-C 6H 4 have been studied in the gas phase using gas electron diffraction (GED) and ab initio methods. The structure of 1-Cl,4-F-C 6H 4 in the crystalline phase has also been studied, but whilst the gaseous structures were found to possess C 2v symmetry, the solid-state structure was found to be quite distorted, with three molecules in the asymmetric unit. These fragments only possess C s symmetry in the plane of the molecules, as opposed to the C 2v symmetry observed in the gas phase. The bonding motifs within the solid-state structure are very unusual and unexpected, with quite different C-F bond lengths for the three moieties, and are a result of weak hydrogen-halogen interactions within the structure. \ua9 2010 Springer Science+Business Media, LLC.Peer reviewed: YesNRC publication: Ye

Molecular structure of 3,3-diethylpentane (tetraethylmethane) in the gas phase as determined by electron diffraction and ab initio calculations

The molecular structure of 3,3-diethylpentane (tetraethylmethane) in the gas phase has been determined by electron diffraction and ab initio calculations at the MP2/6-31G* level. Five local minima on the potential energy surface were located, but only two have significant populations at room temperature. The experimental distribution of conformers was found to be 66(2)% with D(2d) symmetry and 34(2)% with S symmetry, corresponding to an energy difference ΔH°in favor of the D(2d) form of 3.3(2) kJ mol. The molecule shows significant distortion from regular tetrahedral coordination at the central carbon atom, with two CCC angles in the D(2d) form reduced to 106.7(8)°and two angles in the S form increased to 110.9(4)°. These distortions are attributed to asymmetry of the electron density distribution around the CH groups