Influence of Multiple Binding Sites on the Supramolecular Assembly of N-[(3-pyridinylamino) Thioxomethyl] Carbamates

In this study, we investigated how the presence of multiple intermolecular interaction sites influences the heteromeric supramolecular assembly of N-[(3-pyridinylamino) thioxomethyl] carbamates with fluoroiodobenzenes. Three targets-R-N-[(3-pyridinylamino) thioxomethyl] carbamate (R = methyl, ethyl, and isobutyl)-were selected and crystallized, resulting in three parent structures, five co-crystals, and one co-crystal solvate. Three hydrogen-bonded parent crystal structures were stabilized by N-H center dot center dot center dot N hydrogen bonding and assembled into layers that stacked on top of one another. Molecular electrostatic potential surfaces were employed to rank binding sites (Npyr > C=S > C=O) in order to predict the dominant interactions. The N-HMIDLINE HORIZONTAL ELLIPSISH hydrogen bond was replaced by IMIDLINE HORIZONTAL ELLIPSISNpyr in 3/6 cases, IMIDLINE HORIZONTAL ELLIPSISC=S in 4/6 cases, and IMIDLINE HORIZONTAL ELLIPSISO=C in 1 case. Interestingly, the IMIDLINE HORIZONTAL ELLIPSISC=S halogen bond coexisted twice with IMIDLINE HORIZONTAL ELLIPSISNpyr and IMIDLINE HORIZONTAL ELLIPSISO=C. Overall, the MEPs were fairly reliable for predicting co-crystallization outcomes; however, it is crucial to also consider factors such as molecular flexibility. Finally, halogen-bond donors are capable of competing for acceptor sites, even in the presence of strong hydrogen-bond donors.