Iodo-nitroarenesulfonamides: interplay of hard and soft hydrogen bonds, I...O interactions, and aromatic p...p stacking interactions

Molecules of N-(4'-iodophenylsulfonyl)-4-nitroaniline, 4-O2NC6H4NHSO2C6H4I-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-IC6H4NHSO2C6H4NO2-4' (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(SO2C6H4NO2-3')(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 pi...pi stacking interactions. In N-(4'-iodophenylsulfonyl)-3-nitroaniline, 3-O2NC6H4NHSO2C6H4I-4' (4), there are R-2(2)(8) rings formed by hard N-H...O=S hydrogen bonds and R-2(2)(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 pi...pi stacking interactions links the chains into sheets. Molecules of N-(4'-iodophenylsulfonyl)-4-methyl-2-nitroaniline, 4-CH3-2-O2NC6H3NHSO2C6H4I-4'(5), are linked by N-H...O=S and C-H..O(nitro) hydrogen bonds into a chain containing alternating R-2(2)(8) and R-2(2)(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-O2NC6H4NHSO2C6H4I-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.