IUCr journals

1,2,3-Triiodobenzene

Acta Cryst. (2007). E63, o438–o439 [doi:10.1107/S1600536806054535]

[Triiodobenzene] Structure of 1,2,3-triiodobenzene, which relieves I–I steric repulsion by splaying.
Steric repulsion between bulky substituents is of considerable interest to structural chemists. We reported the crystal and molecular structure of 1,2,3-triiodobenzene, which shows evidence of splaying, i.e. the outer iodines are pushed away from the middle iodine by non-bonding repulsions. This is evidenced by the ICC angles, which increase from 118.8° in 1,3,5-triiodobenzene to 123° in 1,2,3-triiodobenzene. The endocyclic CCC angle (at the carbon carrying the middle iodine) decreases from 121.5 to 118.7°, respectively. Interestingly, the I–I distances (3.60 Å) are much smaller than the sum of the van der Waals radii (4.3 Å).

I. Novak and D. Li