4-Aminopyridinium 4-aminobenzenesulfonate 4-ammoniobenzenesulfonate monohydrate

Abstract

The asymmetric unit of the title compound, C5H7N2 +·C6H6NO3S−·C6H7NO3S·H2O, contains one 4-ammonio­benzene­sulfonate zwitterion (+H3NC6H4SO3 −), one 4-amino­benzene­sulfonate anion (H2NC6H4SO3 −), one 4-amino­pyridinium cation and two half-mol­ecules of water, each lying on a twofold rotation axis. The various ions and molecules in the structure are linked through N—H⋯O, N—H⋯N and N—H⋯S hydrogen bonds and C—H—π inter­actions into a three-dimensional framework.

The ephemeral dihydrate of sulfanilic acid

“…4, we compare the conformations of the structurally characterized sulfanilic acid zwitterions. The sulfanilic acid molecule forming a cocrystal with its pyridinium salt (DIWPOP; Fun et al, 2008) is included in this synopsis. In contrast, the only example of a sulfafanilic acid zwitterion acting as a ligand involves coordination to a sterically demanding lead(II)-phenanthroline complex (XEHVEN; Mirtamizdoust et al, 2012) and is not suitable for direct comparison.…”

Crystal structure of diethylammonium aniline-4-sulfonate anilinium-4-sulfonate

“…We report here the synthesis and structure of the product arising from the mixing of diethylamine and anilinesulfonic acid solutions, which contains a combination of ions and a zwitterion. In terms of other compounds containing both the anilinesulfonate anion and its zwitterionic form, aniliniumsulfonate, to date only the 4-aminopyridinium salt has been reported (Fun et al, 2008).…”

“…A search of the Cambridge Structural Database (Version 5.37 + one update; Groom et al, 2016) shows 46 hits concerning the anilinesulfonate anion, three containing aniliniumsulfonate and one hit with both (Fun et al, 2008), while 303 hits concern the diethylammonium ion.…”