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Figure 9
(a) Polymorph I of the 2:1 SM–345THBA co-crystal. An infinite tape is formed by N—H⋯O dimers between symmetry-independent SM molecules (shown in different colours), with peripheral imide carbonyls involved in hydrogen bonding with the acid and hydroxyl OH groups of the 345THBA molecules. The hydroxyl groups of 345THBA adopt a cis–cis–trans conformation. (b) In polymorph II, one of the symmetry-independent SM molecules (shown in green) forms Thomo-II units, and makes an N—H⋯O bond with the other symmetry-independent SM molecule (shown in magenta) through its peripheral imide in an orthogonal fashion. The hydroxyl groups adopt an all trans conformation. Dotted lines indicate hydrogen bonds.

IUCrJ
Volume 2| Part 3| April 2015| Pages 341-351
ISSN: 2052-2525
doi:10.1107/S2052252515002651