Three 3D Supramolecular Organic Salts Assembled from Melamine and Aliphatic Carboxylic Acids: Preparation, Crystallographic Characterization, and Hirshfeld Surface Analysis

• Published in: Journal of chemical crystallography 2024, Vol.54 (3), p.209-224
• Main Authors: Li, Zhaozhi, Lin, Xuele, Gao, Xingjun, Jin, Shouwen, Gong, Xusen, Wang, Daqi
• Format: Article
• Language: English
• Subjects: Bonding strength; Carboxylic acids; Chemistry; Chemistry and Materials Science; Covalence; Crystallography; Crystallography and Scattering Methods; Hydrogen bonds; Inorganic Chemistry; Itaconic acid; Melamine; Organic salts; Organometallic Chemistry; Original Paper; Physical Chemistry; Surface analysis (chemical)
• ISSN: 1074-1542; 1572-8854
• DOI: 10.1007/s10870-024-01014-5

Three crystalline organic salts (melamine) 2 : (itaconic acid): 3H 2 O [(Hmem) 2 2+ ·(itca 2− )·(H 2 O) 3 , itca 2− = itaconate] (1) , (melamine) 2 :(2-bromo-but-2-enedioic acid):DMF:2H 2 O [(Hmem + ) 2 ·(bbda 2− )·DMF·(H 2 O) 2 , bbda 2− = 2-bromo-but-2-enedioate] (2) and (melamine):(α-ketoglutaric acid) [(Hmem + )·(Hketglua − ), Hketglua − = hydrogen α-ketoglutarate] (3) were featured by X-ray diffraction analysis, IR, mp, and elemental analysis. Significant non-covalent interactions were calculated by means of the Hirshfeld surface analysis. All salts involve extensive N–H···OH-bonds as well as other non-covalent associations. The melamine polymers/dimers were set up at 1 – 2 / 3 by the pair of complmentary N–H···NH-bonds. The role of these non-covalent interactions in the crystal packing is ascertained. These weak interactions combined, all salts exhibited 3D framework motifs. Graphical Abstract The crystal structures of the salts from melamine, itaconic acid, 2-bromo-but-2-enedioic acid and α-ketoglutaric acid are predominantly stabilized by the classical hydrogen bonds as well as CH2···O, CH3···O, Br···Br, C···C, O···C, and π···π interactions.