Polymorphism of a widely used building block for halogen‐bonded assemblies: 1, 3, 5‐trifluoro‐2, 4, 6‐triiodobenzene. Issue 9 (4th August 2017)

• Record Type: Journal Article
• Authors: Raffo, Pablo A.; Suárez, Sebastián; Fantoni, Adolfo C.; Baggio, Ricardo; Cukiernik, Fabio D.
• Is Part Of: Acta crystallographica. Volume 73:Issue 9(2017)
• Page Start: 667
• Page End: 673
• Publication Date: 2017-08-04
• Subjects: additive‐induced polymorphism -- atoms in molecules (AIM) -- crystal structure -- halogen bonding -- noncovalent interactions -- melting point -- cohesion energy; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229617011007
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : A new polymorph of 1, 3, 5‐trifluoro‐2, 4, 6‐triiodobenzene is reported. On the basis of the experimental melting points and enthalpies, and also the calculated cohesion energies, the relative stabilities of both polymorphs have been established and analyzed in terms of the crystal structures and the noncovalent interactions present. Abstract : After reporting the structure of a new polymorph of 1, 3, 5‐trifluoro‐2, 4, 6‐triiodobenzene (denotedBzF3I3 ), C6 F3 I3, (I), which crystallized in the space group P 21 / c, we perform a comparative analysis with the already reported P 21 / n polymorph, (II) [Reddy et al. (2006). Chem. Eur. J. 12, 2222–2234]. In polymorph (II), type‐II I…I halogen bonds and I…π interactions connect molecules in such a way that a three‐dimensional structure is formed; however, the way in which molecules are connected in polymorph (I), through type‐II I…I halogen bonds and π–π interactions, gives rise to an exfoldable lamellar structure, which looks less tightly bound than that of (II). In agreement with this structural observation, both the melting point and the melting enthalpy of (I) are lower than those of (II).