STRUCTURE DETERMINATION OF 1,2-DIMETHOXYETHANE AND THE RELATED COMPOUNDS BY USING A NEW DIFFRACTOMETER. Yoshihiro Yokoyama, Hidehiro Uekusa, and Yuji Ohashi

Department of Chemistry, Faculty of Science, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152

The crystal structure of 1,2-dimethoxyethane(DME) and the related compounds, which are low-melting-point materials, have been determined. Although these structures have long been subject of interest for conformational studies as the monomer model of poly(oxyethylene), the crystal structures have not been reported from difficulty in getting the single crystal at low temperatures.

Recently a new imaging plate-Weissenberg camera type diffractometer with a new low temperature equipment was designed and made. This equipment enable us to perform the rapid intensity data collection before ice is formed on the surface of the crystal.

The crystal of DME belongs to the monoclinic system and the space group is C2/c. There are four molecules in an unit cell. The DME molecule lies on a two-fold axis and has a TGT conformation, which is not most stable among the possible conformations, in the crystalline state.

When the two oxygen atoms were replaced with two sulfur atoms, the conformation was changed to GTG' conformation.