Relationship between crystal shape and unit cell shape: crystal shape modification via co-crystallization toward SXRD-suitable crystals

We demonstrated that crystal shape is related to the unit cell shape and that a molecular arrangement can be altered as desired by employing co-crystallization. We investigated the relationship between the crystal shape, unit cell parameters, and intermolecular interactions using 131 crystals of secondary aromatic sulfonamides. The crystal shape was evaluated based on the unit cell length ratio (M/S, L/S) (L, M, S = the longest, mid-length, and shortest cell lengths, respectively), and was considered block-like if the ratio was close to (1, 1) and needle-like if it was not. Furthermore, when the sulfonamides that yielded needle-like crystals were co-crystallized with 4,4 '-dipyridyl (dpy), the (M/S, L/S) ratio of the obtained co-crystals was close to (1, 1); that is, the co-crystals were more block-like than the crystals of the original compound. Thus, co-crystallization is useful for obtaining block-like crystals suitable for single-crystal X-ray diffraction (SXRD).