Content area
Full Text
news & views
PHOTOISOMERIZATON
Molecular motors driven by light
The demonstration of light-powered unidirectional molecular motion suggests that a new breed of articial nanoscale motors and pumps could be a realityin the near future. Giulio Ragazzonand co-workers at the Photochemical Nanosciences Laboratory at the University of Bologna in Italy report how a molecular axle can be made to move through a macrocycle ring following illumination with ultraviolet light (Nature Nanotech. http://dx.doi.org/10.1038/nnano.2014.260
Web End =http://dx.doi.org/10.1038/nnano.2014.260 ; 2014). The axle is composed of three parts: a photoswitchable E-azobenzene unit at one end (green/red structurein image), a central ammonium recognition site (purple) and a passive methylcylopentyl pseudo-stopperat the other end (white sphere). The macrocycle ring (pink) is composed of 2,3-dinaphtho[24]crown-8 ether 124.
With the appropriate illumination, a photoisomerization reaction is triggered and the photoswitchable end of the axle changes from an E-2+ conguration (green) to a bent Z-2+ state (red) and
the axle moves relative to the ring. For irradiation with 365nm light, the E to Z...