title: Reversing the direction in a light-driven rotary molecular motor.
abstract: Biological rotary motors can alter their mechanical function by changing the direction of rotary motion. Achieving a similar reversal of direction of rotation in artificial molecular motors presents a fundamental stereochemical challenge: how to change from clockwise to anticlockwise motion without compromising the autonomous unidirectional rotary behaviour of the system. A new molecular motor with multilevel control of rotary motion is reported here, in which the direction of light-powered rotation can be reversed by base-catalysed epimerization. The key steps are deprotonation and reprotonation of the photochemically generated less-stable isomers during the 360° unidirectional rotary cycle, with complete inversion of the configuration at the stereogenic centre. The ability to change directionality is an essential step towards mechanical molecular systems with adaptive functional behaviour.
authors.affiliation: Centre for Systems Chemistry, Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747AG, The Netherlands.
authors.forename: Nopporn
authors.initials: N
authors.lastname: Ruangsupapichat
authors.forename: Michael M
authors.initials: MM
authors.lastname: Pollard
authors.forename: Syuzanna R
authors.initials: SR
authors.lastname: Harutyunyan
authors.forename: Ben L
authors.initials: BL
authors.lastname: Feringa
mesh_terms: D007536:Isomerism; D008027:Light; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000528:radiation effects*; D009038:Motion; D046912:Multiprotein Complexes / Q000737:chemistry / Q000528:radiation effects*; D011522:Protons; D012399:Rotation
chemical_list: D020409:Molecular Motor Proteins; D046912:Multiprotein Complexes; D011522:Protons