Research Article: 8,10-Diiodo-2,6-dioxo-4λ3-ioda-3,5-dioxatricyclo­[,11]undeca-1(11),7,9-triene-9-carb­oxy­lic acid

Date Published: March 01, 2012

Publisher: International Union of Crystallography

Author(s): Daopeng Sheng, Lu Han, Yi Zhang, Yanzhao Yang.


In the title compound, C9HI3O6·2H2O, the mol­ecule is located on a twofold axis that gives rise to disorder of the carboxyl group. This disorder is correlated with the disorder of one of the H atoms of the water mol­ecule. The carboxyl group is twisted relative to the attached benzene ring by 75.1 (4)°. The intra­molecular I⋯O distance is 2.112 (6) Å. Mol­ecules are linked via O—H⋯O hydrogen bonding, C—I⋯O halogen bonding, with I⋯O distances in the range 3.156 (5)–3.274 (6) Å, and dipolar C=O⋯C=O inter­actions between the carboxyl and carboxyl­ate groups, with an O⋯C distance of 2.944 (10) Å.

Partial Text

For general background to 1,3,5-triiodo­benzene derivatives, see: Morin et al. (1987 ▶); Yu & Watson (1999 ▶). For information on the related compound 1,3,5-triiodo-2,4,6-trimethyl­benzene, see: Bosch & Barnes (2002 ▶); Boudjada et al. (2001 ▶); Reddy et al. (2006 ▶). For the crystal structures of 5-amino-2,4,6-triiodo­isophthalic acid monohydrate and 5-amino-2,4,6-triiodo­isophthalic acid–4,4′-bipyridine N,N′-dioxide–water (1/1/1), see: Beck & Sheldrick (2008 ▶); Zhang et al. (2011 ▶).