Scientists are trying to create molecular systems that mimic machinery components. The idea is for these molecular machines to exhibit mechanical movement once an external stimulus is applied.
With this in mind, Japanese researchers have grown crystals that bend upon shining UV light on them. The crystals are of a salicylideneaniline compound which changes its structure depending on the wavelength of light.
The molecular transformation from the enol to the trans-keto form causes the crystals to bend on the macroscopic scale, which is also accompanied by a colour change from pale yellow to reddish-orange. When the UV light is blocked, the crystals resume their initial straight form and colour. This reversible bending can be repeated for over 200 cycles.
To find out more, download Koshima’s ChemComm article.
