Synthesis, Crystal Structure and Supramolecular Features of Novel 2,4-Diaminopyrimidine Salts

The study explores the synthesis and crystal structures of four novel 2,4-diaminopyrimidine salts, focusing on their supramolecular architectures and intermolecular interactions. The primary interaction mode is the N-H∙∙∙N interaction, forming R22(8) homosynthons, with additional N-H∙∙∙O interactions creating R12(6) motifs. Hirshfeld surface analysis shows that H∙∙∙H interactions are the most significant, contributing up to 41% to crystal packing, alongside O∙∙∙H/H∙∙∙O and N∙∙∙H/H∙∙∙N contacts. The study highlights the role of π∙∙∙π stacking and C-O∙∙∙π contacts, while sulfur-based interactions are minimal. The research underscores the diversity in molecular packing and synthon formation among the salts.