Self-Entagled States of Linear Catenanes in Poor Solvent: Knots and Threadings

We used molecular dynamics simulations to explore self-entanglements in collapsed linear catenanes, unveiling two types of topologically complex states. Firstly, we observed numerous and long-lasting knots in the catenane backbone. However, when compared to traditional polymers, these knots were notably less probable in catenanes. Secondly, we identified complex topological states that lack counterparts in polymers. In these states, concatenated rings were threaded by other nearby or distant rings, sliding through them. Unlike knots, these threaded states could disentangle by becoming fully tightened. We employed a thermodynamic and microscopic analysis of these entagled states, rationalizing their persistence and disentanglement modes.