A curious case of dynamic disorder in pyrrolidine rings elucidated by NMR crystallography. Issue 90 (26th October 2020)

• Record Type: Journal Article
• Authors: Szell, Patrick M. J.; Brown, Steven P.; Hughes, Leslie P.; Blade, Helen; Nilsson Lill, Sten O.
• Is Part Of: Chemical communications. Volume 56:Issue 90(2020)
• Page Start: 14039
• Page End: 14042
• Publication Date: 2020-10-26
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1039/d0cc05236a
• Languages: English
• ISSNs: 1359-7345

Abstract

Abstract : Pseudosymmetric pyrrolidine groups exhibiting distinct dynamics are investigated by solid-state NMR and DFT, uncovering the origins to this contrast. Abstract : A pharmaceutical exhibits differing dynamics in crystallographically distinct pyrrolidine rings despite being nearly related by symmetry, with one performing ring inversions while the other is constrained to torsional librations. Using 13 C solid-state magic-angle spinning (MAS) NMR and DFT calculations, we show that this contrast originates from C–H⋯H–C close contacts and less efficient C–H⋯π intermolecular interactions observed in the transition state of the constrained pyrrolidine ring, highlighting the influence of the crystallographic environment on the molecular motion.