Pyrimethamine as a versatile Coformer for 7 multicomponent crystalline salts: preparation, spectral, structural diversity, synthons investigation and Hirshfeld surface analysis

• Eight pma-acid supramolecular salts were synthesized. • Their accurate structures were illucidated by the various techniques. • The supramolecular systems were built by a broad set of non-covalent bonds. • The graph-set descriptors were also illuminated. • The conformations of the Hpma were analyzed. Pyrimethamine (pma) is a very old antimalarial drug. In this job by means of the neutralization reaction of the pma molecule and the respective mineral and organic carboxylic acids, seven bi-, tri-, tetra- and penta-component crystalline salt systems are produced by the gradual solvent volatilization technique. The detailed features have been thoroughly conducted by the set of the analytical performances encompassing the single crystal X-ray diffraction(SC-XRD), IR and EA, the melting points (m.p.s) were also surveyed. Their structural and supramolecular facets were analyzed in detail according to the noncovalent associates and the supramolecular synthons. The impact of the chief intermolecular interactions was evaluated further by the Hirshfeld surface analysis (HSA) suite of program for illucidating their importances. For the crystal structures of all the organic salts, the pyrimidines are protonized at one of the cyclic ring Ns ( i.e. the N contiguous to the ethyl arm) and which subsequently interplayed with the acid residues via the charge-assisted, robust, and directional classical Hbonds given by the NH + to demonstrate the H-bonded cyclic bimolecular motif. Apart from 4 , the both inversion related motifs were mated by a pair of the N H⋯N Hbonds between an unprotonated ring nitrogen and the 4-amino at the both cations. Besides this pairwise, one of the carboxylate/alcohol oxygens bridges the 2- and 4-amino groups on both sides of the pairing to produce a complementary DADA (D is the H-bond donor and A is the H-bond acceptor) array of the quadruple Hbonds at 2–3 and 5–7 . For 1 the Br bridged the 2- and 4-amino units on both sides of the pairing to get a complementary DADA too. In 4 , there exist no base-pairing, and only established the cyclic H-bonded bimolecular motif. Apart from the N H⋯O/N H⋯N H-bond, the O H···O H-bonds were also appeared at 2 – 3 & 5 – 7. 1 exhibited the extra N H···Br Hbond. In-depth check of the crystal packing declared that a distinct set of the extra CH 3 CH 3 /CH CH, CH 3 C, CH 3 ···N/CH···N, CH 3 O/CH 2 ···O/CH O, CH 3 Cl, CH-Br/CH 3 -Br, CH 3 -π/CH 2 -π/CH-π, N H···π, C-π, Cl-π & π-π associates facilitate the stabilization and propagation of the 2D-3D complicated graphs. On account of the interreaction of the various nonbonding associates these structures displayed the homo/hetero supramolecular synthons. The classical synthons R 2 2 (8) & R 3 2 (8), usually encountered in the solids architectured by the carboxylic acids-diaminopyrimidine, were again occurred in the job. The work here laid the solid foundation for flourishing the new organic crystalline solids encompassing the pma , and provided some novel idea into its salts.