title: Multiple hindered rotators in a gyroscope-inspired tribenzylamine hemicryptophane.
abstract: A gyroscope-inspired tribenzylamine hemicryptophane provides a vehicle for exploring the structure and properties of multiple p-phenylene rotators within one molecule. The hemicryptophane was synthesized in three steps in good overall yield using mild conditions. Three rotator-forming linkers were cyclized to form a rigid cyclotriveratrylene (CTV) stator framework, which was then closed with an amine. The gyroscope-like molecule was characterized by (1)H NMR and (13)C NMR spectroscopy, and the structure was solved by X-ray crystallography. The rigidity of the two-component CTV-trismethylamine stator was investigated by (1)H variable-temperature (VT) NMR experiments and molecular dynamics simulations. These techniques identified gyration of the three p-phenylene rotators on the millisecond time scale at -93 °C, with more dynamic but still hindered motion at room temperature (27 °C). The activation energy for the p-phenylene rotation was determined to be ~10 kcal mol(-1). Due to the propeller arrangement of the p-phenylenes, their rotation is hindered but not strongly correlated. The compact size, simple synthetic route, and molecular motions of this gyroscope-inspired tribenzylamine hemicryptophane make it an attractive starting point for controlling the direction and coupling of rotators within molecular systems.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Najat S
authors.initials: NS
authors.lastname: Khan
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Perez-Aguilar
authors.forename: Tara
authors.initials: T
authors.lastname: Kaufmann
authors.forename: P Aru
authors.initials: PA
authors.lastname: Hill
authors.forename: Olena
authors.initials: O
authors.lastname: Taratula
authors.forename: One-Sun
authors.initials: OS
authors.lastname: Lee
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Carroll
authors.forename: Jeffery G
authors.initials: JG
authors.lastname: Saven
authors.forename: Ivan J
authors.initials: IJ
authors.lastname: Dmochowski
mesh_terms: D001596:Benzylamines / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D011083:Polycyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D001596:Benzylamines; D011083:Polycyclic Compounds; C523242:cryptophane; C480307:tribenzylamine