Crystal structure of the 1:1 co-crystal 4-(di-methylamino)-pyridin-1-ium 8-hy-droxy-quinoline-5-sulfonate- N, N-di-methyl-pyridin-4-amine

Abstract

The asymmetric unit of the title compound is composed of two independent ion pairs of 4-(di-methyl-amino)-pyridin-1-ium 8-hy-droxy-quinoline-5-sulfonate (HDMAP⁺·HqSA^-, C₇H₁₁N₂ ⁺·C₉H₆NO₄S^-) and neutral N,N-di-methyl-pyridin-4-amine mol-ecules (DMAP, C₇H₁₀N₂), co-crystallized as a 1:1:1 HDMAP⁺:HqSA^-:DMAP adduct in the monoclinic system, space group Pc. The compound has a layered structure, including cation layers of HDMAP⁺ with DMAP and anion layers of HqSA^- in the crystal. In the cation layer, there are inter-molecular N-H⋯N hydrogen bonds between the protonated HDMAP⁺ mol-ecule and the neutral DMAP mol-ecule. In the anion layer, each HqSA^- is surrounded by other six HqSA^-, where the planar network structure is formed by inter-molecular O-H⋯O and C-H⋯O hydrogen bonds. The cation and anion layers are linked by inter-molecular C-H⋯O hydrogen bonds and C-H⋯π inter-actions.

Keywords: DMAP; N—H⋯N inter­actions; co-crystal; crystal structure; quinolin-8-ol sulfonate.