Abstract
Two crystalline inner salts 3-carboxy-2-(quinolinium-1-ylmethyl)propanoate dihydrate (1), and 3-(3-carbamoylpyridinium-1-yl)-2-(carboxymethyl)propanoate (2) were featured by the X-ray diffraction analysis, IR, mp, and elemental analysis. Salt 1 crystallizes in the triclinic, space group P-1, with a = 7.8315(8) Å, b = 11.1063(12) Å, c = 11.3763(14) Å, α = 67.5800(10)º, β = 82.295(2)º, γ = 80.970(2)º,V = 900.38(17) Å3, Z = 2. Salt 2 adopts the monoclinic, space group P2(1)/n, with a = 8.4782(8) Å, b = 7.7825(7) Å, c = 16.8649(17) Å, β = 97.999(2)º, V = 1101.95(18) Å3, Z = 4. Both salts comprise the extensive O-H···O H-bonds as well as other non-covalent associates. The percentage contribution of the significant non-covalent contacts were calculated via the Hirshfeld surface analysis. The hetero supramolecular synthons R21(6), R22(10), R22(12), R22(13), R22(14), R22(16), R22(22), R33(9), R42(8), R43(10), and R55(17) were established at the both salts. Most of the synthons were not found repeatedly, yet the R22(10) was established at the both cases. The role of these non-covalent interactions in the crystal structure extension is ascertained. These weak interactions combined together, both salts exhibited the 3D framework structures.