Hierarchy of ab initio and DFT methods for describing an intramolecular non-covalent Si⋅⋅⋅N contact in the silicon compounds using electron diffraction geometries

In the series of silatranes XSi(OCH2CH2)3N, 1 (X = Me, 1a; H, 1b; F, 1c) with the known gas electron diffraction (GED) structures, the problematic geometry of 1-methylsilatrane 1a has...

Gas Electron Diffraction Then and Now: from trisilyl phosphine to iso-propyl(tert-butyl)(trichlorosilyl)phosphine

The gas-phase molecular structure of iso-propyl(tert-butyl)(trichlorosilyl)phosphine has been determined using a combination of gas electron diffraction and computational methods. The structure presents a conformational challenge that required use of the...

Inter- and Intramolecular Aryl-Aryl-Interactions in Partially Fluorinated Ethylenedioxy-Bridged Bisarenes

Several ethylenedioxy-bridged bisarenes with a variety of type and number of aryl groups were synthesized to study non-covalent dispersion-driven inter- and intramolecular aryl-aryl-interactions in the solid state and gas phase. Intramolecular interactions are preferably found in the gas phase. DFT calculations of dispersion-corrected energy scans for rotations around the ethylenedioxy-bridge and optimized structures show larger interacting aromatic groups to increase the dispersion energy. Single molecule structures generally adopt folded conformations with short intramolecular aryl-aryl-contacts. Gas electron diffraction experiments were performed exemplarily for 1-(pentafluorophenoxy)-2-(phenoxy)ethane. A new procedure for structure refinement was developed to deal with the conformational complexity of such molecules. The results are an experimental confirmation of the existence of folded conformations of this molecule with short -intramolecular aryl-aryl distances in the gas phase. Solid-state structures are dominated by stretched structures without intramolecular aryl-aryl-interactions but interactions with neighboring molecules<br>

Inter- and Intramolecular Aryl-Aryl-Interactions in Partially Fluorinated Ethylenedioxy-Bridged Bisarenes

Several ethylenedioxy-bridged bisarenes with a variety of type and number of aryl groups were synthesized to study non-covalent dispersion-driven inter- and intramolecular aryl-aryl-interactions in the solid state and gas phase. Intramolecular interactions are preferably found in the gas phase. DFT calculations of dispersion-corrected energy scans for rotations around the ethylenedioxy-bridge and optimized structures show larger interacting aromatic groups to increase the dispersion energy. Single molecule structures generally adopt folded conformations with short intramolecular aryl-aryl-contacts. Gas electron diffraction experiments were performed exemplarily for 1-(pentafluorophenoxy)-2-(phenoxy)ethane. A new procedure for structure refinement was developed to deal with the conformational complexity of such molecules. The results are an experimental confirmation of the existence of folded conformations of this molecule with short -intramolecular aryl-aryl distances in the gas phase. Solid-state structures are dominated by stretched structures without intramolecular aryl-aryl-interactions but interactions with neighboring molecules<br>