2,4-Diamino-6-phenyl-1,3,5-triazin-1-ium nitrate: intriguing crystal structure with high Z′/Z′′ and hydrogen bond numbers and Hirshfeld surface analysis of intermolecular interactions?

CrystEngComm Pub Date: 2021-04-16 DOI: 10.1039/D1CE00313E

Abstract

2,4-Diamino-6-phenyl-1,3,5-triazine-1-ium nitrate (LH)(NO3) crystallises in the triclinic centrosymmetric space group P[1 with combining macron] with an intriguing high number of crystallographically unique salt-like adducts (Z′ = 8) and a total number of ionic species (Z′′ = 16) in the asymmetric unit. The organic cations and nitrate anions are combined into two similar H-bonded neutral tapes strengthening by 20 unique NH?O and NH?N hydrogen bonds each. Hydrogen bonds are ordered into a repeated sequence of homo- and hetero-synthons, R22(8)R33(10)R22(8)R22(8)R24(8)R33(10) as ring motifs. The paired cations form R22(8) ring motifs through base pairing of N–H?N hydrogen bonds. All other patterns include both cations and anions. In the crystal structure, the compromise between the tapes rigidity provided by the multiple directional H-bonds within the tapes and packing preferences is reached through the restricted internal rotation about the C–C bond joining the phenyl and triazine cycles in the 2,4-diamino-6-phenyl-1,3,5-triazine-1-ium cations. The decisive impact of NH?O(N) hydrogen bonds in the crystal stability and distribution of other types of intermolecular interactions was estimated by Hirshfeld surface analysis. The undertaken CSD overview for the metal-free L-based crystals reveals the exclusivity of the title compound from the viewpoint of the high reported Z′/Z′′ values and the number of unique hydrogen bonds.

Graphical abstract: 2,4-Diamino-6-phenyl-1,3,5-triazin-1-ium nitrate: intriguing crystal structure with high Z′/Z′′ and hydrogen bond numbers and Hirshfeld surface analysis of intermolecular interactions
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