title: Crystal structure of 2,4-di-amino-6-oxo-3,6-di-hydro-pyrimidin-1-ium p-toluene-sulfonate.
abstract: In the title salt, C4H7N4O(+)·C7H7O3S(-), the 2,6-di-amino-4-oxo-1,3-di-hydro-pyrimidin-1-ium cation inter-acts with the sulfonate group of the p-toluene-sulfonate anion via a pair of N-H⋯O hydrogen bonds, forming a hetero-synthon R 2 (2)(8) that mimics the role of a carboxyl-ate. The self-assembled cations form a homo-synthon R 2 (1)(6) motif which is further linked with the sulfonate anion via N-H⋯O hydrogen bonds to generate an R 3 (2)(10) ring motif. The three motifs are fused together and extended as supra-molecular ribbons along the b-axis direction. Adjacent ribbons are further linked via N-H⋯O hydrogen bonds to form an annulus, with an R 4 (4)(20) ring motif, resulting in a tunnel-like arrangement propagating along [010]. There are slipped parallel π-π stacking inter-actions [inter-centroid distance = 3.6539 (7) Å], between the tunnel-like polymer chains, forming slabs parallel to (100).
authors.affiliation: Department of Chemistry, Periyar Maniammai University, Thanjavur 613 403, Tamil Nadu, India.
authors.forename: Krishnasamy
authors.initials: K
authors.lastname: Mamallan
authors.affiliation: Department of Chemistry, Periyar Maniammai University, Thanjavur 613 403, Tamil Nadu, India.
authors.forename: Sadasivam Sharmila
authors.initials: SS
authors.lastname: Tagore
authors.affiliation: Department of Chemistry, Periyar Maniammai University, Thanjavur 613 403, Tamil Nadu, India.
authors.forename: Sundaramoorthy
authors.initials: S
authors.lastname: Gomathi
authors.affiliation: Department of Chemistry, Periyar Maniammai University, Thanjavur 613 403, Tamil Nadu, India.
authors.forename: Velusamy
authors.initials: V
authors.lastname: Sethuraman
keywords: N—H⋯O hydrogen bonds; crystal structure; di­amino­pyrimidines; hydrogen bonding; p-toluene­sulfonate; tri­amino­pyrimidines; π–π stacking inter­actions