Crystal structures and hydrogen bonding in the proton-transfer salts of nicotine with 3,5-di­nitro­salicylic acid and 5-sulfosalicylic acid

Abstract

The crystal structures of the 1:1 salts of nicotine with 3,5-di­nitro­salicylic acid and with 5-sulfosalicylic acid both show polymeric hydrogen-bonded and π–π-bonded structures but these differ in that in the first example, cations and anions form separate cation chains or anion columns which are unassociated through formal hydrogen bonds while in the second, hydrogen-bonded cation–anion chains are found.

Abstract

The structures of the 1:1 anhydrous salts of nicotine (NIC) with 3,5-di­nitro­salicylic acid (DNSA) and 5-sulfosalicylic acid (5-SSA), namely (1 R,2 S)-1-methyl-2-(pyridin-3-yl)-1 H-pyrrolidin-1-ium 2-carb­oxy-4,6-di­nitro­phenolate, C ₁₀H ₁₅N ₂ ⁺·C ₇H ₃N ₂O ₇ ⁻, (I), and (1 R,2 S)-1-methyl-2-(pyridin-3-yl)-1 H-pyrrolidin-1-ium 3-carb­oxy-4-hy­droxy­benzene­sulfonate, C ₁₀H ₁₅N ₂ ⁺·C ₇H ₅O ₆S ⁻, (II), are reported. The asymmetric units of both (I) and (II) comprise two independent nicotinium cations ( C and D) and either two DNSA or two 5-SSA anions ( A and B), respectively. One of the DNSA anions shows a 25% rotational disorder in the benzene ring system. In the crystal of (I), inter-unit pyrrolidinium N—H⋯N _pyridine hydrogen bonds generate zigzag NIC cation chains which extend along a, while the DNSA anions are not involved in any formal inter-species hydrogen bonding but instead form π–π-associated stacks which are parallel to the NIC cation chains along a [ring-centroid separation = 3.857 (2) Å]. Weak C—H⋯O inter­actions between chain substructures give an overall three-dimensional structure. In the crystal of (II), A and B anions form independent zigzag chains with C and D cations, respectively, through carb­oxy­lic acid O—H⋯N _pyridine hydrogen bonds. These chains, which extend along b, are pseudocentrosymmetrically related and give π–π inter­actions between the benzene rings of anions A and B and the pyridine rings of the NIC cations C and D, respectively [ring centroid separations = 3.6422 (19) and 3.7117 (19) Å]. Also present are weak C—H⋯O hydrogen-bonding inter­actions between the chains, giving an overall three-dimensional structure.