Helical fluxionality: numerical frustration drives concerted low-barrier screw motions of a tricopper cluster. Issue 12 (1st March 2023)

• Record Type: Journal Article
• Authors: Kim, Heechan; Shin, Juhwan; Kim, Seyong; Lee, Dongwhan
• Is Part Of: Chemical science. Volume 14:Issue 12(2023)
• Page Start: 3265
• Page End: 3269
• Publication Date: 2023-03-01
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d3sc00851g
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : An uneven distribution of ligand donor atoms and metal centers of a double-helical trinuclear complex drives a hitherto unknown type of fluxional motion taking a spiral path with an extraordinarily low energy barrier. Abstract : Uneven allocation of resources creates frustration, tension, and conflicts. Confronted with an apparent mismatch between the number of donor atoms and the number of metal atoms to be supported, helically twisted ligands cleverly come up with a sustainable symbiotic solution. As an example, we present a tricopper metallohelicate exhibiting screw motions for intramolecular site exchange. A combination of X-ray crystallographic and solution NMR spectroscopic studies revealed thermo-neutral site exchange of three metal centres hopping back and forth inside the helical cavity lined by a spiral staircase-like arrangement of ligand donor atoms. This hitherto unknown helical fluxionality is a superimposition of translational and rotational movements of molecular actuation, taking the shortest path with an extraordinarily low energy barrier without compromising the overall structural integrity of the metal–ligand assembly.