N,N-Dimethylbenzylamine as a Coformer for 3 Crystalline Organic Salts: Preparation, Spectral, Structural Investigation, Synthons Diversity and Hirshfeld Surface Analysis

In this work by means of the neutralization reaction of the N,N-dimethylbenzylamine, 3,5-dinitrobenzoic acid, 3,5-dinitrosalicylic acid and naphthalene-1,5-disulfonic acid, three bi- and tri-component crystalline salt systems are made by the gradual solvent volatilization method. The detailed features have been thoroughly conducted by the set of the analytical performances embracing the single crystal X-ray diffraction (SC-XRD), IR and EA, the melting points (m.p.s) were also measured. Their structural and supramolecular facets were analyzed in detail according to the noncovalent linkages and the supramolecular synthons. The role of the major intermolecular contacts was evaluated further by the Hirshfeld surface analysis (HSA) suite of programme for illucidating their importances. All the salts demonstrated the 3D net structures for the collective effect of the various non-covalent contacts. All contained the identical mol stoichiometry of 1:1 rate between the dmba & the number of the acidic units and embraced the N–H···O & O–H···O Hbonds together with the other non-covalent connections. Within all the salts, the respective residues are permanently tethered to each other via the energetic Hbonds belonging to the ionic N_{N,N-dimethylbenzylaminium}–O_acid fashion. Other extensive non-covalent connections of CH···O/CH₂···O/CH₃···O, C_π···π, CH···π/CH₃···π and π···π also function appreciable roles in the spatial expandings. The salts demonstrated the R₂²(4), R₂²(7), R₂²(12), R₂²(15), R₄³(11), R₄³(12), R₄⁴(20), R₄⁴(22), R₆⁵(30) and R₈⁸(44) rings. For the synergism of the traditional Hbonds and the diversified non-covalent connections, all applied the 3D appearances.

Graphical Abstract

The structures of the salts from dmba, 3,5-dinitrobenzoic acid, 3,5-dinitrosalicylic acid, and naphthalene-1,5-disulfonic acid are predominantly stabilized by the classical Hbonds together with the CH···O/CH₂···O/CH₃···O, C_π···π, CH···π/CH₃···π & π···π associates, erecting the 3D graphs.