Computational and Experimental Study Linking Polysulfamide Chain Design to the Hydrogen Bonding Induced Chain Aggregation

Poly-N, N’-disubstituted sulfamides [Kulow et al. <i>Chem. Sci.</i>, 2020, <b>11</b>, 7807-7812], a new class of polymers structurally analogous to polyureas, are gaining attention in organocatalysis and medicinal chemistry. It is essential to have a fundamental understanding of poly-N, N’-disubstituted sulfamides to facilitate their wider commercial applications as replacements of polyureas. In this talk, we present a collaborative computational and experimental study of polysulfamide chains and their assembly driven by hydrogen bonding interactions between the sulfamide groups. We first share our newly developed coarse-grained (CG) model of polysulfamide that captures the directionality of inter-chain hydrogen bonds between sulfamide groups and allows us to study self-assembly of polysulfamide chains in molecular dynamics (MD) simulations. These simulations link the contour length, bulkiness, and flexibility of the N, N’-substituents on either side of the sulfamide groups to the morphology (e.g., positional and orientational order) of the polysulfamide assembly. We validate our CG model and simulation approaches by showing that the MD simulation results agree with the trend in assembly crystallinity for various aliphatic and aromatic N, N’-substituent chemistries measured by X-ray diffraction (XRD) and infrared (IR) in experiments. We then use the validated computational approach to explore new substituent chemistries and study the effects of substituent length and bulkiness on morphology of polysulfamide self-assembly, with the predictions tested against additional experimental syntheses and characterizations.