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Updated: Mar 25, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Crystal structures of two bis-(iodo-meth-yl)benzene derivatives: similarities and differences in the crystal packing
C John McAdam1, Lyall R Hanton1, Stephen C Moratti1
1Department of Chemistry, University of Otago, PO Box 56, Dunedin, New Zealand.
Abstract:
The isomeric derivatives 1,2-bis-(iodo-meth-yl)benzene, (I), and 1,3-bis-(iodo-meth-yl)benzene (II), both C8H8I2, were prepared by metathesis from their di-bromo analogues. The ortho-derivative, (I), lies about a crystallographic twofold axis that bis-ects the C-C bond between the two iodo-methyl substituents. The packing in (I) relies solely on C-H⋯I hydrogen bonds supported by weak parallel slipped π-π stacking inter-actions [inter-centroid distance = 4.0569 (11) Å, inter-planar distance = 3.3789 (8) Å and slippage = 2.245 Å]. While C-H⋯I hydrogen bonds are also found in the packing of (II), type II, I⋯I halogen bonds [I⋯I = 3.8662 (2) Å] and C-H⋯π contacts feature prominently in stabilizing the three-dimensional structure.
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