title: Pressure-induced pseudorotation in crystalline pyrrolidine.
abstract: Pressure of 1.14(3) GPa leads to the crystallization of a new β phase of pyrrolidine, where every second molecule pseudorotates to the CH(2)-off envelope conformation, energetically less favored than the NH-off envelope. The β phase is triclinic, space group P ̅1, but it is isostructural with monoclinic phase α, where all molecules are in the N-off envelope conformation. The energy associated with the pseudorotation constitutes only about 5% of the total energy change. The energetically unfavorable axial N-H position is retained.
authors.affiliation: Faculty of Chemistry, Adam Mickiewicz University, Poznań, Poland.
authors.forename: Kamil F
authors.initials: KF
authors.lastname: Dziubek
authors.forename: Andrzej
authors.initials: A
authors.lastname: Katrusiak
mesh_terms: D000588:Amines / Q000737:chemistry; D003460:Crystallization; D006860:Hydrogen Bonding; D011312:Pressure; D011759:Pyrrolidines / Q000737:chemistry*; D012399:Rotation
chemical_list: D000588:Amines; D011759:Pyrrolidines; C032519:pyrrolidine