Crystal structure of 6,7-dimethoxy-triptycenequinone.

derivatives, a weak intermolecular donor-acceptor (D-A) interaction between the quinone (A) and the benzene or methylsubstituted benzene (D) moieties contributes to connect the molecules to a ribbon-like supramolecular unit.1,2 It seems reasonable that the benzene moiety substituted by methyl groups, which is better donor, tend to participate in the D-A interaction preferentially, for example in the case of 6,7dimethyl-TPQ. The o-dimethoxybenzene moiety in the title compound (1) is favorable for such a D-A interaction based on the elevated donor ability. On the other hand, however, its bulkiness seems to be unfavorable for the interaction, because D and A fragments of neighboring molecules must come close together to make a face-to-face contact between them. We determined the crystal structure of 1 in order to investigate which function is dominant in the crystalline state. The compound was prepared according to the literature.3 The single crystal of 1 used in the X-ray work was crystallized from its benzene solution. Reflections were measured on a Rigaku-AFC5R diffractometer with Mo Kα radiation (2θ < 50 ̊) at 295 K. Crystal data and experimental details are given in Table 1. The structure was solved by a direct method. Non-hydrogen atoms and the hydrogen atoms, except for those cited below, were included in the structure refinements without any constraints applying anisoand iso-tropic displacement parameters, respectively. The positions of the hydrogen atoms (H2, H11, H12, H13 and H15) were calculated, and were included in the refinement with isotropic displacement parameters. Structure refinements against all F2 data (3138 reflections) gave Rw = 1405 ANALYTICAL SCIENCES DECEMBER 2002, VOL. 18 2002 © The Japan Society for Analytical Chemistry