Seven 3D organic salts from 2-(imidazol-1-yl)-1-phenylethanone and acidic components

Abstract Cocrystallization of 2-(imidazol-1-yl)-1-phenylethanone with a series of organic acids gave seven crystalline salts with the compositions: 2-(imidazolium-1-yl)-1-phenylethanone trifluoroacetate (1) [(HL) + · (tfa) - , tfa −  = trifluoroacetate], bis(2-(imidazolium-1-yl)-1-phenylethanone) bis(hydrogen fumarate) monohydrate (2) [(HL) 2 2+ · (Hfum) 2 2− · H 2 O, Hfum = hydrogen fumarate], 2-(imidazolium-1-yl)-1-phenylethanone 3,5-dinitrobenzoate (3) [(HL) + · (dnb − ), dnb −  = 3,5-dinitrobenzoate], 2-(imidazolium-1-yl)-1-phenylethanone 5-sulfosalicylate (4) [(HL) + · (Hssa − ), Hssa −  = 5-sulfosalicylate], bis(2-(imidazolium-1-yl)-1-phenylethanone) 1,5-naphthalenedisulfonate (5) [(HL) 2 2+ · (npa 2− ), npa 2−  = 1,5-naphthalenedisulfonate], 2-(imidazolium-1-yl)-1-phenylethanone 3-nitrohydrogenphthalate (6) [(HL + ) · (Hnpta − ), Hnpta −  = 3-nitrohydrogenphthalate], and 2-(imidazolium-1-yl)-1-phenylethanone 4-nitrohydrogenphthalate (7) [(HL) + · (Hnpa) - , Hnpa −  = 4-nitrohydrogenphthalate]. The seven salts have been characterized by XRD technique, IR, and elemental analysis, and the melting points of all salts were also reported. Their structural and supramolecular aspects are fully analyzed. The result reveals that in all the seven investigated crystalline solids the 3-N of the ring in 2-(imidazol-1-yl)-1-phenylethanone moieties are protonated when the organic acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted N H⋯O H-bond from the NH + and the deprotonated acidic groups. In addition to the N H⋯O H-bond, the O H⋯O H-bonds were also found at 2 , 4 , and 6 – 7 . Further analysis of the crystal packing of the salts told that a different set of additional CH O/CH 2 O, CH F, F F, CH-π, OH-π, O O, O-C π and O-π associations contribute to the stabilization and expansion of the total 3D framework structures. For the interplay of the various weak nonbonding interactions these structures adopted homo or hetero supramolecular synthons or both. The classical supramolecular synthons of R 2 2 (7) and R 2 2 (8), usually observed in organic solids of organic acids with imidazole, were again shown to be participated in constructing most of these H-bonding networks.