J. Am. Chem. Soc., 132, 14172-14178 (2010)
Photomechancial effect of a two-component co-crystal composed of a photochromic
diarylethene derivative, 1,2-bis(2-methyl-5-(1-naphthyl)-3-thienyl)perfluorocyclopentene
(1o), and perfluoronaphthalene (FN) was studied. The plate crystal of 1o・FN
with the size of 1~5 mm in length exhibits reversible bending motion upon
alternate irradiation with ultraviolet (UV) and visible light. The reversible
bending can be repeated over 250 times. In situ X-ray crystallographic analysis revealed that the deformation of the crystal
is induced by the shape change of component diarylethene molecules upon
photocyclization. Molecular crystal cantilevers made of 1o・FN can lift
metal balls, the weight of which is 200~600 times heavier than the weight
of the crystal, upon UV irradiation. The maximum stress generated by UV
irradiation was estimated to be 44 MPa, which is 100 times larger than
that of muscles (~0.3 MPa) and comparable to that of piezoelectric crystals,
such as lead zirconate titanate (PZT) (~50 MPa).
A Diarylethene Cocrystal that Converts Light into Mechanical
Work