Structure determination of organic compounds using an in-laboratory rapid X-ray measurement system – comparison with structures determined by a four-circle diffractometer

A new type of X-ray diffractometer (IPD-WAS) has been recently developed as a rapid X-ray measurement system in the laboratory. This equipment has been closely examined from the viewpoint of a tool for the data collection of organic crystals. Intensities of two stable compounds [I : bis(2,4,6-trimethylthiobenzoic) thioanhydride; II : dimethyl 1,2-di-tert-butyl-3,6-dimethyl 4,5-dicarboxylate] and one unstable compound (III : tri-4-methylphenylbismuth dichloride) were measured with Mo Kα radiation, with the total time for the intensity measurement being 2 or 3h for each compound. 1995, 2360 and 2502 independent reflections of 3520, 5238 and 5397 measured reflections were used for structure determination for (I), (II) and (III), respectively. The structures were solved successfully by conventional direct methods and the Patterson method. The final R values were 0.055, 0.050 and 0.067 for (I), (II) and (III), respectively. For (I) and (II), intensities were also measured with a four-circle diffractometer using the same specimens, the final R values being 0.058 and 0.055 for 2733 and 3224 reflections for (I) and (II), respectively. The agreement between the two sets of structural geometry, obtained from the IPD-WAS and the four-circle diffractometer, was quite satisfactory. Accurate intensities of the unstable (III) could not be obtained by the four-circle diffractometer.