Hydrogen Bonding Patterns in 2,6-diamino-4-oxopyrimidinium Sulfosalicylate Monohydrate

Abstract

The title compound, [C4H7N4O+, C7H5O6S− . H2O] contains one 2, 6-diamino-4-oxopyrimidinium cation, one sulfosalicylate anion and a water molecule. The crystal structure was determined by single crystal X-ray diffraction. This compound crystallized in the orthorhombic system; space group Pna21 with the unit cell parameters a = 13.402(3) A, b = 16. 221(3) A, c = 6.714(2) A, V = 1459.6(6), Z = 4. The sulfonic acid group has protonated the aminopyrimidine moiety. The protonated N1 atom and N4 amino group are hydrogen bonded to the keto group (O1) of the neighbouring pyrimidine forming a six-membered ring with graph-set notation R2 1(6) and a supramolecular chain along the c-axis. This supramolecular chain is further strengthened by one of the sulfonate oxygen atoms (O3), bridging the pyrimidines via hydrogen bonded rings, R 3 2(10) involving N(3)–H(3)···O(3) and N(2)–H(2B)···O(3) hydrogen bonds. The other two oxygen atoms of the sulfonate groups are bridged by water molecules via O-H···O hydrogen bonds constituting a supramolecular chain. The water molecule also acts as hydrogen bond acceptor with respect to the carboxyl group.