Date Published: August 01, 2012
Publisher: International Union of Crystallography
Author(s): Kulandaiya Rajamani, Doraisamyraja Kalaivani.
In the title molecular salt [systematic name: triethylammonium 1,3-dimethyl-2,6-dioxo-5-(2,4,6-trinitrophenyl)-1,2,3,6-tetrahydropyrimidin-4-olate], C6H16N+·C12H8N5O9−, the dihedral angle between the aromatic rings in the anion is 46.88 (8)°. The nitro group para to the ring junction is almost coplanar with its attached ring [dihedral angle = 0.76 (3)°], but the two ortho-nitro groups are substantially twisted from the ring plane, by 47.91 (2) and 42.90 (1)°. In the crystal, the cation and anion are linked by an N—H⋯O=C hydrogen bond; these dimeric associations are further connected by weak C—H⋯O bonds to form linear supramolecular chains extending in the  direction.
For background to barbiturates, see: Tripathi (2009 ▶). For our recent work in this area, see: Kalaivani & Buvaneswari, 2010 ▶); Kalaivani & Malarvizhi (2009 ▶); Buvaneswari & Kalaivani (2011 ▶); Babykala & Kalaivani (2012 ▶).