Polymorphism of a widely used building block for halogen-bonded assemblies: 1,3,5-trifluoro-2,4,6-triiodobenzene

FANTONI, ADOLFO C.; SUAREZ, SEBASTIÁN; RAFFO, PABLO A.; BAGGIO, RICARDO; CUKIERNIK, FABIO D.

Acta Crystallographica Section C: Structural Chemistry

International Union of Crystallography

Lugar: Londres; Año: 2017 vol. 73 p. 667 - 673

After reporting the structure of a new polymorph of 1,3,5-trifluoro-2,4,6triiodobenzene (denoted BzF3I3), C6F3I3, (I), which crystallized in space group P21/c, we perform a comparative analysis with the already reported P21/n polymorph, (II) [Reddy et al. (2006). Chem. Eur. J. 12, 2222?2234]. In polymorph (II), type-II I...I halogen bonds and I...Pi 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 Pi?Pi 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).