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Polymorphism in 3‐acetyl‐4‐hydroxy‐2 H ‐chromen‐2‐one
Author(s) -
Ghouili Afef,
Brahmia Ameni,
Ben Hassen Rached
Publication year - 2015
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229615016083
Subject(s) - intramolecular force , crystallography , hydrogen bond , chemistry , intermolecular force , polymorphism (computer science) , molecule , stacking , crystal structure , delocalized electron , stereochemistry , organic chemistry , biochemistry , genotype , gene
A new polymorph (denoted polymorph II) of 3‐acetyl‐4‐hydroxy‐2 H ‐chromen‐2‐one, C 11 H 8 O 4 , was obtained unexpectedly during an attempt to recrystallize the compound from salt–melted ice, and the structure is compared with that of the original polymorph (denoted polymorph I) [Lyssenko & Antipin (2001). Russ. Chem. Bull. 50 , 418–431]. Strong intramolecular O—H...O hydrogen bonds are observed equally in the two polymorphs [O...O = 2.4263 (13) Å in polymorph II and 2.442 (1) Å in polymorph I], with a slight delocalization of the hydroxy H atom towards the ketonic O atom in polymorph II [H...O = 1.32 (2) Å in polymorph II and 1.45 (3) Å in polymorph I]. In both crystal structures, the packing of the molecules is dominated and stabilized by weak intermolecular C—H...O hydrogen bonds. Additional π–π stacking interactions between the keto–enol hydrogen‐bonded rings stabilize polymorph I [the centres are separated by 3.28 (1) Å], while polymorph II is stabilized by interactions between α‐pyrone rings, which are parallel to one another and separated by 3.670 (5) Å.