X-RAY CRYSTAL STRUCTURE ANALYSIS BY A NEW DIFFRACTOMETER USING IMAGING PLATES. Hidehiro UEKUSA and Yuji OHASHI, Department of Chemistry, Tokyo Institute of Technology, Ookayama, Tokyo 152, JAPAN.

Recently we have designed and made a new type of diffractometer using two imaging plates for rapid data collection. The new diffractometer is a Weissenberg camera type mechanism with a feature of a k-type goniometer, two imaging plates, and spiral motion reading mechanism. The total accuracy of the new diffractometer is comparable to that of a four circle diffractometer despite a very short measurement time. It is also equipped with a new type of variable temperature system using nitrogen gas stream, which covers a temperature range of 80 K to 420 K.

Following experiments are successfully performed by this diffractometer.

(1) Structure determination of the X-ray sensitive molecule. The initial molecular structure of syn-tricyclooctane derivative has been determined for the first time by 140 minutes measurement, which has not been analyzed due to the rapid bond cleavage reaction under X-ray irradiation.

(2) Data collection without sealing in a glass capillary. Despite of the bad condition that the crystal was easily decomposed by the loss of solvent methanol, the structure of cobalt(II) complex with N-glycoside, which is a model of metal containing enzyme, has been determined by 160 minutes measurement without sealing at room temperature.

(3) Structure after phase transition. The structural change of an organic charge transfer complex due to the phase transition has been clarified by utilizing the low temperature equipment and rapid data collection.