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1,3,5-Triiodo-2,4,6-trimethylbenzene at 293 K
A Boudjada1, O Hernandez, J Meinnel
1Laboratoire de Cristallographie, Département de Physique, Université Mentouri Constantine, 25000 Constantine, Algeria.
Summary
Triiodomesitylene exhibits significant benzene ring distortion from ideal symmetry due to iodine and methyl group positioning. This structural analysis provides insights into halogenated aromatic compound geometry.
Area of Science:
- Crystallography
- Organic Chemistry
- Molecular Structure
Background:
- Mesitylene derivatives are important in organic synthesis and materials science.
- Understanding the impact of heavy halogen substitution on aromatic ring geometry is crucial.
Purpose of the Study:
- To determine the precise crystal structure of triiodomesitylene at 293 K.
- To analyze the distortions in the benzene ring caused by iodine and methyl group substitution.
- To compare the structural features with isomorphous chloro- and bromo-analogs.
Main Methods:
- Single-crystal X-ray diffraction at 293 K.
- Rigid-body motion tensor analysis for thermal motion.
- Analysis of intra- and intermolecular contacts.
Main Results:
- The benzene ring in triiodomesitylene is significantly distorted from D(6h) symmetry.
- Average endocyclic angles are 123.8 (3)° towards iodine and 116.2 (3)° towards methyl groups.
- The molecular plane is tilted by 5.1° relative to the (100) crystallographic plane; no disorder was observed.
Conclusions:
- The heavy iodine substituents induce substantial geometric distortions in the mesitylene core.
- Topological differences exist compared to trichloromesitylene and tribromomesitylene, highlighting the effect of halogen size.
- The study provides valuable structural data for halogenated aromatic compounds.