Macromolecular Topology Engineering

Macromolecular topology mainly concerns the connectivity and spatial relationship of molecular segments as defined by the bonding threshold and entanglement in space. Four elemental types of macromolecular topology (i.e., branched structures, multicyclic structures, knots, and links) are identified and their combination further contributes to the beauty and complexity of macromolecular topology. Nature provides many excellent examples of topological macromolecules and inspires macromolecular topology engineering. Assembly-reaction synergy has emerged as a powerful approach for the synthesis of topological macromolecules. Topology is a unique dimension for macromolecular engineering. The topological effects on a macromolecule could be understood in terms of changing molecular shape, reshaping conformational space, and bringing in dynamic features. Topology is an intriguing topic in chemistry and an important molecular attribute for macromolecules. Herein, we discuss the concept of topology in different contexts to clarify the meaning and scope of macromolecular topology. The beauty and complexity of macromolecular topology is recognized and presented. Relevant advances in the syntheses and structure–property relationship of topological polymers are summarized. Among them, assembly-reaction synergy has emerged as a particularly powerful approach to prepare topological polymers. Indeed, these topologically nontrivial macromolecules exhibit unique properties not found in their linear counterparts. Current challenges and prospects are then discussed, pointing to a growing dynamic field of macromolecular topology engineering. Topology is an intriguing topic in chemistry and an important molecular attribute for macromolecules. Herein, we discuss the concept of topology in different contexts to clarify the meaning and scope of macromolecular topology. The beauty and complexity of macromolecular topology is recognized and presented. Relevant advances in the syntheses and structure–property relationship of topological polymers are summarized. Among them, assembly-reaction synergy has emerged as a particularly powerful approach to prepare topological polymers. Indeed, these topologically nontrivial macromolecules exhibit unique properties not found in their linear counterparts. Current challenges and prospects are then discussed, pointing to a growing dynamic field of macromolecular topology engineering. a type of knot in Alexander–Briggs notation. The main number 8 denotes the number of crossings and the subscript 19 is the rank of this knot that differentiates it from others with the same number of crossings (Figure 2). a synthetic method involving assembly to prearrange molecule(s) into specific 3D geometry with a defined spatial relationship with subsequent covalent fixation to give molecules of complex topologies. a chemical philosophy that describes perfectly ideal chemical reactions with features such as excellent yields, spring-loaded reactivity, non-offensive byproducts, operational facility, high selectivity, and modularity. consists of two rings linked together exactly once. It is the simplest nontrivial link with more than one component (Figure 2). an entanglement in space between two or more molecular entities (component parts) such that they cannot be separated without breaking or distorting chemical bonds between atoms. a graph constructed to represent a polymer structure with the vertex being a branch point (i.e., a collection of atoms) and the edge being a linear structure (i.e., a chain of bonds between two branch points). It has facilitated the analysis and systematic nomenclature of polymer topology. the θ-curves are embeddings of the Greek letter θ in the 3D space. In macromolecules, they are a class of polymers with the topology of θ-curves.