posted on 2019-06-11, 00:00authored byJacqueline M. Cole, Jose de J. Velazquez-Garcia, David J. Gosztola, SuYin Grass Wang, Yu-Sheng Chen
Single-crystal optical
actuators are emerging as a prospective
material form for nano-optical mechanical switching, sensing, or transduction
device applications in nanotechnology and quantum technology. Crystal-lattice
strain effects lie at the molecular origins of their macroscopic optical
behavior, and linkage photoisomerization is an attractive source of
optical actuation, if only suitably functioning materials of this
ilk could be found. We discover η1-SO2 to η1-OSO single-crystal linkage photoisomerization
in [Ru(NH3)4(SO2)(3-phenylpyridine)]Cl2·H2O, which behaves macroscopically as a single-crystal
optical actuator, whereby the crystal peels in response to light-induction
at 100 K. It thermally recovers, whereupon the crystal exhibits remarkable
restorative properties. We apply photocrystallography alongside concerted
optical microscopy and optical absorption spectroscopy to reveal how
the molecular origins of photoisomerization induce crystal-lattice
strain that engenders this macroscopic crystal peeling effect. Linking
structure and function across molecular and macroscopic length scales
showcases a means by which single-crystal optically actuating materials
could be systematically designed.