Polymorphism of a widely used building block for halogen-bonded assemblies: 1,3,5-Trifluoro-2,4,6-Triiodobenzene
RAFFO, PABLO A.; SUÁREZ, SEBASTIÁN; FANTONI, ADOLFO C.; BAGGIO, RICARDO; CUKIERNIK, FABIO D.
Acta Crystallographica Section C: Structural Chemistry
John Wiley and Sons Inc.
Año: 2017 vol. 73 p. 667 - 667
After reporting the structure of a new polymorph of 1,3,5-Trifluoro-2,4,6-Triiodobenzene (denoted BzF3I3), C6F3I3, (I), which crystallized in the 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..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).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.