Coexistence of two halide hydrate clusters in a crystal of 1,1′-(benzene-1,3-diyldimethanediyl)-bis(3,5,7-triaza-1-azoniatricyclo[3.3.1.13,7]decane) dibromide trihydrate. X-ray structure, Hirshfeld surface and thermal analysis

Abstract

The title compound, C20H32N82+·2Br−·3H2O, was obtained by the reaction of 1,3,5,7-triazatricyclo[3.3.1.13,7]decane with 1,3-bis(bromomethyl)benzene in acetonitrile. The asymmetric unit contains a unique 1,1′-(benzene-1,3-diyldimethanediyl)bis(3,5,7-triaza-1-azoniatricyclo[3.3.1.13,7]decane)dication, two bromide anions and three water molecules. The 3,5,7-triaza-1-azoniatricyclo[3.3.1.13,7]decane (C6N4H12)+ moieties lie on the same side of the molecule, and the pseudo torsion angle (H12N4C6)CH2⋯CH2(C6N4H12) is −5.25 (18)°. The molecular dication C20H32N8+ is charge-balanced by a pair of crystallographically independent halide hydrate clusters, and the cation and clusters are interlinked by CH⋯O and CH⋯Br hydrogen bonds. The Hirshfeld surface analysis and fingerprint plots reveal that the packing in compound 2 is directed mainly by H⋯H (56.7%) and H⋯Br/Br⋯H (21.3%) contacts. The thermal analysis showed between 30 and 180 °C the gradual loss of three water molecules, which represents the loss of one and two crystalline water molecules from the two types of clusters, respectively. A second noticeable weight loss between 180 and 230 °C is observed, depictive of the thermal decomposition of the dication of the title compound.

Keywords

• Crystal structure
• Water cluster
• Water halide cluster
• Hexamethylenetetramine
• Hydrogen bonding
• Halogen bonding