Sulfonamide-Pyridine-N-oxide Cocrystals

Hydrogen-bond motifs for the supramolecular synthesis of sulfonamide-pyridine-N-oxide complexes were derived from the analysis of cocrystal structures of aryl sulfonamides and pyridine-N-oxides. The sulfonamide NH donor persistently interacts with the N-oxide acceptor via a N-H center dot center dot center dot O hydrogen bond, though the exact geometry of the motif; such as discrete (D), infinite chain C(4), cyclic motifs R-4(2)(8) or R-2(2)(4), varies from structure to structure. Surprisingly, the two-point R-2(2)(8) cyclic motif of N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, analogous to the heterosynthon in carboxamide-pyridine-N-oxide cocrystals, was not observed in sulfonamide N-oxide cocrystals. The utility of this model study is demonstrated by making cocrystals of Furosemide with 4,4'-bipyridine-N,N'-dioxide and isonicotinamide-N-oxide.