title: Driving unidirectional molecular rotary motors with visible light by intra- and intermolecular energy transfer from palladium porphyrin.
abstract: Driving molecular rotary motors using visible light (530-550 nm) instead of UV light was achieved using palladium tetraphenylporphyrin as a triplet sensitizer. Visible light driven rotation was confirmed by UV/vis absorption, circular dichroism and (1)H NMR spectroscopy and the rotation was confirmed to be unidirectional and with similar photostationary states, despite proceeding via a triplet instead of a singlet excited state of the molecular motor. Energy transfer proceeds in both inter- and intramolecular fashion from the triplet state of the porphyrin to the motor. Stern Volmer plots show that the rate of intermolecular quenching of the porphyrin excited state by the molecular motor is diffusion-controlled.
authors.affiliation: Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty of Mathematics and Natural Sciences, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.
authors.forename: Arjen
authors.initials: A
authors.lastname: Cnossen
authors.forename: Lili
authors.initials: L
authors.lastname: Hou
authors.forename: Michael M
authors.initials: MM
authors.lastname: Pollard
authors.forename: Philana V
authors.initials: PV
authors.lastname: Wesenhagen
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; D004735:Energy Transfer; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D013056:Spectrophotometry, Ultraviolet
chemical_list: D008665:Metalloporphyrins