title: Topological dynamics in supramolecular rotors.
abstract: Artificial molecular switches, rotors, and machines are set to establish design rules and applications beyond their biological counterparts. Herein we exemplify the role of noncovalent interactions and transient rearrangements in the complex behavior of supramolecular rotors caged in a 2D metal-organic coordination network. Combined scanning tunneling microscopy experiments and molecular dynamics modeling of a supramolecular rotor with respective rotation rates matching with 0.2 kcal mol(-1) (9 meV) precision, identify key steps in collective rotation events and reconfigurations. We notably reveal that stereoisomerization of the chiral trimeric units entails topological isomerization whereas rotation occurs in a topology conserving, two-step asynchronous process. In supramolecular constructs, distinct displacements of subunits occur inducing a markedly lower rotation barrier as compared to synchronous mechanisms of rigid rotors. Moreover, the chemical environment can be instructed to control the system dynamics. Our observations allow for a definition of mechanical cooperativity based on a significant reduction of free energy barriers in supramolecules compared to rigid molecules.
authors: Physik-Department E20, Technische Universität München , D-85748 Garching, Germany.
authors: Carlos-Andres
authors: CA
authors: Palma
authors: Jonas
authors: J
authors: Björk
authors: Francesco
authors: F
authors: Rao
authors: Dirk
authors: D
authors: Kühne
authors: Florian
authors: F
authors: Klappenberger
authors: Johannes V
authors: JV
authors: Barth
mesh_terms: D056004:Molecular Dynamics Simulation; D058608:Nanopores / Q000648:ultrastructure*; D012399:Rotation