A POSSIBLE CRYSTAL-STRUCTURE OF 1,2-DIMETHOXYETHANE - PREDICTION BASED ON A LATTICE VARIABLE MOLECULAR-DYNAMICS

Using a newly developed method based on a lattice-constant variable molecular dynamics, the crystal structure of 1,2-dimethoxyethane (DME) has been predicted to consist of TGT conformers packed in Pnaa spatial symmetry. The prediction was carried out using our MDCP (Molecular Dynamics for Crystal Packing) program with van der Waals potentials of the MM3 force field and partial charges fitted to ab initio molecular orbital electrostatic potential. The predicted TGT conformation in the crystal agrees with the results of infrared absorption spectroscopy on solid DME. The packing analysis shows that the preference of TGT over TTT (in the gas phase TTT is the most stable) is mainly due to the Coulombic attractions between intermolecular O...CH2 pairs as well as the Coulombic repulsions between intermolecular O...O pairs.