6-Bromo-1H-indole-2,3-dione hemihydrate

Abstract

The title compound, C8H4BrNO2·0.5H2O, has a single planar molecule in the asymmetric unit with the non-H atoms having a mean deviation from planarity of 0.028 Å. There is also a half of a water molecule (twofold symmetry) present in the asymmetric unit, which hydrogen bonds with the isatin molecules through O—H...O and N—H...O hydrogen bonds to form a two-dimensional framework in theabplane. There are close Br...O contacts of 2.999 (2) Å to link the layers. The nine-membered rings of the isatin molecules stack along theaaxis with parallel slipped π–π interactions [inter-centroid distances = 3.6989 (19) and 4.1227 (19) Å].

5,6-Dibromo-1H-indole-2,3-dione

“…Of note in the structure are Br2Á Á ÁO2 close contacts of 2.9409 (3) Å , with the bromine substituted at the 6 position of the isatin ring. In previous reports, 6-bromoisatin (Turbitt et al, 2016) was found to have a similar interaction, which was also observed in 4-bromoisatin (Huang et al, 2016) and 7-bromoisatin (Golen & Manke, 2016a). Interestingly, Br1, which is at the 5-position of the isatin is not involved in a BrÁ Á ÁO interaction.…”

4-Bromo-1H-indole-2,3-dione

“…The structure of the title compound demonstrates an intermolecular Br1Á Á ÁO2 ii close contact of 3.0430 (14) Å , symmetry code: (ii) Àx + 2, Ày, Àz + 1. A similar bromo-oxygen interaction is observed in the structure of 6-bromoisatin (Turbitt et al 2016), though no such halogen-oxygen interactions are observed for the derivatives of 4-chloroisatin (Hughes et al, 2010;Wang et al, 2012;Yu et al, 2012) In the crystal, the molecules dimerize through N1-H1Á Á ÁO1 hydrogen bonds (Table 1). The nine-membered rings of the isatins stack along [001] with parallel slippedinteractions [inter-centroid distance: 3.7173 (6) Å , inter-planar distance: 3.3110 (8) Å , slippage: 1.6898 (14) Å ].…”

5-Bromo-1H-indole-2,3-dione

“…The structure exhibits a near planar molecule with the nonhydrogen atoms possessing a mean deviation from planarity of 0.024 Å , with similar bond lengths and angles to those observed in isatin (Goldschmidt et al, 1950). The structure of other bromoisatins report short BrÁ Á ÁO contacts (Huang et al, 2016;Turbitt et al, 2016), which are not observed in 5-bromoisatin. The structures of N-subsistuted derivatives of 5bromoisatin have been reported (Kurkin et al, 2008;Maamri et al, 2012) with only one instance of a BrÁ Á ÁO interaction being observed (Kharbach et al, 2015).…”