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Figure 4
(a) Two molecules of 2 in the asymmetric unit viewed perpendicular to the pyranoxanthone rings to highlight π–π stacking. The pyranoxanthone core atoms of the first and second molecules are labeled in black and gray, respectively. (b) Stacking of 2 in the unit cell. The unit cell is shown as a gray box where the b axis is parallel to the reader's view. The a and c axes and the origin center are labeled in the figure. |