One hundred 4,4′-disubstituted benzenesulfonamidobenzenes, X–C6H5–SO2–NH–C6H5–Y, where X, Y = NO2, CN, CF3, I, Br, Cl, F, H, Me, OMe, have been synthesized and their crystal structures determined. The resulting set of 133 structures, which includes polymorphic forms, is used to make a comparative study of the molecular packing and the nature of the intermolecular interactions, including the formation of hydrogen-bonding motifs and the influence of the two substituents X and Y on these features. Nine distinct supramolecular connectivity motifs of hydrogen bonding are encountered. There are 74% of all the structures investigated which exhibit one of two motifs based on N—H...O=S interactions, a dimer or a chain. There are three other, infrequent motifs, also employing N—H...O=S links, which exhibit more complexity. Four different chain motifs result from either N—H...O=N, N—H...C[triple-bond]N or N—H...OMe interactions, arising from the presence of a nitro (position Y), nitrile (X or Y) or methoxy (Y) substituent. The program XPac [Gelbrich & Hursthouse (2005). CrystEngComm, 7, 324–336] was used to systematically analyse the packing relationships between crystal structures. Similar discrete (zero-dimensional) and extended (one-dimensional and two-dimensional) structure components, as well as cases of isostructurality were identified. A hierarchy for the classification of the 56 distinct structure types of this set is presented. The most common type, a series of 22 isostructures containing the simple centrosymmetric N—H...O=S-bonded dimer, is discussed in detail.
Development and Performance Evaluation of a Small-scale Maize Harvester for Developing Countries