Photochemically Driven Shape Changes of Crystalline Organic Nanorods
Rabih O. Al-Kaysi
Astrid M. Müller
Christopher J. Bardeen
10.1021/ja064535p.s002
https://acs.figshare.com/articles/dataset/Photochemically_Driven_Shape_Changes_of_Crystalline_Organic_Nanorods/3040486
Nanorods composed of 9-<i>tert</i>-butylanthroate (9-TBAE) are synthesized using an Al<sub>2</sub>O<sub>3</sub> template and solvent annealing. The rods consist of micron-scale crystalline domains, and UV light induces a [4 + 4] photodimerization that results in a uniform 15% expansion along the rod axis. This is in contrast to random 9-TBAE crystals, which disintegrate under the same conditions. Transmission electron microscopy, atomic force microscopy, and comparison of the X-ray crystal structures of the monomer and photodimer all provide evidence for a mechanism based on a crystal-to-crystal photoreaction leading to an increase in molecular volume. It is likely that the high surface-to-volume ratio in the nanorods provides a strain relief pathway that is absent in larger crystals. Preliminary attempts to reverse the reaction using shorter wavelength light to photodissociate the dimers were only partly successful. These results suggest that crystalline organic nanostructures may provide an efficient way to transform photochemical energy into mechanical motion on the nanometer scale.
2006-12-20 00:00:00
strain relief pathway
crystal
transmission electron microscopy
Preliminary attempts
Shape Changes
nanometer scale
Al 2O template
UV light
force microscopy
TBAE
wavelength light
Crystalline Organic NanorodsNanorods
rod axis