Iodo-nitroarenesulfonamides: Interplay of hard and soft hydrogen bonds, I⋯O interactions and aromatic π⋯π stacking interactions

Molecules of N-(4′-iodophenylsulfonyl)-4-nitroaniline, 4-O₂NC₆H₄NHSO₂C₆H ₄I-4′ (1), are linked by three-centre I⋯O₂N interactions into chains and these chains are linked into a three-dimensional framework by C-H⋯O hydrogen bonds. In the isomeric N-(4′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC₆H₄NHSO₂C₆H₄NO ₂-4′ (2), the chains generated by the I⋯O₂N interactions are again linked into a three-dimensional framework by C-H⋯O hydrogen bonds. Molecules of N,N-bis(3′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC₆H₄N(SO₂C₆H₄NO ₂-3′)₂ (3), lie across twofold rotation axes in space group C2/c and they are linked into chains by paired I⋯O=S interactions: these chains are linked into sheets by a C-H⋯O hydrogen bond, and the sheets are linked into a three-dimensional framework by aromatic π⋯π stacking interactions. In N-(4′-iodophenylsulfonyl)-3-nitroaniline. 3-O₂NC₆H₄NHSO₂C₆H ₄I4′ (4). there are R²₂(8) rings formed by hard N-H⋯O=S hydrogen bonds and R²₂(24) rings formed by two-centre I⋯nitro interactions, which together generate a chain of fused rings: the combination of a C-H⋯O hydrogen bond and aromatic π⋯π stacking interactions links the chains into sheets. Molecules of N-(4′-iodophenylsulfonvl)-4-methyl-2-nitroaniline, 4-CH₃-2-O₂NC₆H₃NHSO ₂C₆H₄I-4′ (5), are linked by N-H⋯O=S and C-H⋯O(nitro) hydrogen bonds into a chain containing alternating R²₂(8) and R²₂(10) rings, but there are no I⋯O interactions of either type. There are two molecules in the asymmetric unit of N-(4′-iodophenylsulfonyl)-2-nitroaniline, 2-O₂NC₆H₄NHSO₂C₆H ₄I-4′ (6). and the combination of an I⋯O=S interaction and a hard N-H⋯O(nitro) hydrogen bond links the two types of molecule to form a cyclic, centrosymmetric four-component aggregate. C-H⋯O hydrogen bonds link these four-molecule aggregates to form a molecular ladder. Comparisons are made with structures retrieved from the Cambridge Structural Database.