cg7008489_si_004.cif (14.48 kB)

Halogen Bonding Interactions of sym-Triiodotrifluorobenzene with Halide Anions: A Combined Structural and Theoretical Study

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posted on 02.07.2008, 00:00 by Sonia Triguero, Rosa Llusar, Victor Polo, Marc Fourmigué
Cocrystallization of 1,3,5-trifluoro-2,4,6-triiodobenzene (sym-TFTIB) with nBu4NX or Ph4PX (X = Cl, Br) afforded the 1:1 complex salts formulated as (sym-TFTIB)(nBu4NCl), (sym-TFTIB)(nBu4NBr), (sym-TFTIB)(Ph4PCl)(H2O)0.5 or (sym-TFTIB)(Ph4PBr). In all four salts, each halide anion is halogen bonded to three iodine atoms from three different sym-TFTIB molecules, affording a recurrent polymeric two-dimensional anionic network, characterized by short I···X distances and linear C−I···X but acute I···X···I angles (X = Cl, Br). Topological analysis of the electron localization function (ELF) shows a perfect match between the iodine valence shell electrons, with a “belt”-shape arrangement around the C−I axis, and the spherical halide anions. The lack of covalent character for the halogen bond allows the simultaneous participation of one X anion in three halogen bonds.