Molecular Recognition Studies of Thioamide (−CSNH2) Functionality through Co-crystals of Some Thiobenzamides with N-Donor Ligands: Evaluation and Correlation of Structural Landscapes with Morphology and Lattice Energy

Abstract

Molecular recognition studies of supramolecular edifices of thiobenzamide, 1, and its hetero analogues, o- and p-isomers of pyridinethioamides, 2 and 3, respectively, have been reported highlighting the recognition patterns of the thioamides with different aza-donor compounds having variable conformational flexibility and dimensions, for example, 4,4′-bipyridine (bpy, a), 1,2-bis(4-pyridyl)ethene (bpyee, b), 1,10-phenanthroline (110phen, c), and phenazine (phenz, d). The analysis reveals that thioamides 1–3 produce co-crystals, 1(a–d)−3(a–d), respectively, with the corresponding aza-donors. These structures, determined by single-crystal X-ray diffraction, reveal that in all co-crystals, the aggregation of the coformers occurs through N–H···N hydrogen bonds due to the establishment of recognition between the thioamide moiety and the N-hetero atom and is further augmented by C–H···S hydrogen bonds. Analysis of hydrogen-bonding patterns reveals several structural similarities and differences among co-crystals, with the formation of different types of three-dimensional structures in the form of herringbone, layer, and sandwich. A systematic evaluation of solid-state structures was performed in terms of the interplay of competing intermolecular interactions within the crystal lattices and packing features of the resulted exotic architectures, BFDH morphology predictions, and isostructural analysis through cell-similarity index, powder X-ray diffraction similarity, etc. Furthermore, the importance of each type of intermolecular interaction, in particular, N–H···N, N–H···S, C–H···S, etc., has been quantified by Hirshfeld surface analysis. In addition, the energy contribution of all interactions is computed by developing energy frameworks using Crystal Explorer.