title: MHz unidirectional rotation of molecular rotary motors.
abstract: A combination of cryogenic UV-vis and CD spectroscopy and transient absorption spectroscopy at ambient temperature is used to study a new class of unidirectional rotary molecular motors. Stabilization of unstable intermediates is achieved below 95 K in propane solution for the structure with the fastest rotation rate, and below this temperature measurements on the rate limiting step in the rotation cycle can be performed to obtain activation parameters. The results are compared to measurements at ambient temperature using transient absorption spectroscopy, which show that behavior of these motors is similar over the full temperature range investigated, thereby allowing a maximum rotation rate of 3 MHz at room temperature under suitable irradiation conditions.
authors.affiliation: Laboratory for Organic Chemistry, Stratingh Institute for Chemistry, Faculty of Mathematics and Natural Sciences, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Klok
authors.forename: Nicola
authors.initials: N
authors.lastname: Boyle
authors.forename: Mary T
authors.initials: MT
authors.lastname: Pryce
authors.forename: Auke
authors.initials: A
authors.lastname: Meetsma
authors.forename: Wesley R
authors.initials: WR
authors.lastname: Browne
authors.forename: Ben L
authors.initials: BL
authors.lastname: Feringa
mesh_terms: D002942:Circular Dichroism; D003080:Cold Temperature; D003517:Cyclopentanes / Q000737:chemistry*; D012399:Rotation; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet
chemical_list: D003517:Cyclopentanes; D012996:Solutions