Diarylethene Photoswitches Undergoing 6π Azaelectrocyclic Reaction: Disrotatory Thermal Cycloreversion of the Closed-Ring Isomer

Gaining insight into the dynamics of electrocyclic reactions is very important from both fundamental and application perspectives. In this study, we developed novel diarylethene photoswitches that undergo 6π azaelectrocyclic reaction. We found that they exhibit fast thermally reversible type (T-type) photochromism in contrast to the fact that common diarylethenes exhibit photochemically reversible type (P-type) photochromism. The quantum chemical calculations revealed that the fast T-type photochromism originates from the unprecedented disrotatory thermal cycloreversion of the closed-ring isomer. Our results provide useful information not only for the dynamics of the 6π azaelectrocyclic reaction but also for the further development of diarylethene photoswitches utilizing 6π azaelectrocyclic reaction

Crystal Thickness Dependence of Photoinduced Crystal Bending of 1,2-Bis(2-methyl-5-(4-(1-naphthoyl­oxymethyl)­phenyl)-3-thienyl)­perfluoro­cyclo­pentene

The photoinduced crystal bending of a photochromic diaryl­ethene derivative, 1,2-bis­(2-methyl-5-(4-(1-naphthoyl­oxymethyl)­phenyl)-3-thienyl)­perfluoro­cyclo­pentene (<b>1a</b>), has been particularly investigated. The rodlike crystal of <b>1a</b> shows reversible photoinduced bending upon alternating irradiation with ultraviolet (UV) and visible light. The photoinduced crystal bending can be repeated over 80 cycles. The rodlike crystal of <b>1a</b> shows different bending behavior depending on the faces irradiated with UV light. This is ascribed to the molecular orientation viewed from the faces. Furthermore, we found that the bending speed depends on the crystal thickness, and the curvature change against the crystal thickness is well-fitted to Timoshenko’s bimetal model. These findings provide a new useful strategy to design for the photomechanical actuators

Crystal Thickness Dependence of Photoinduced Crystal Bending of 1,2-Bis(2-methyl-5-(4-(1-naphthoyl­oxymethyl)­phenyl)-3-thienyl)­perfluoro­cyclo­pentene

The photoinduced crystal bending of a photochromic diaryl­ethene derivative, 1,2-bis­(2-methyl-5-(4-(1-naphthoyl­oxymethyl)­phenyl)-3-thienyl)­perfluoro­cyclo­pentene (<b>1a</b>), has been particularly investigated. The rodlike crystal of <b>1a</b> shows reversible photoinduced bending upon alternating irradiation with ultraviolet (UV) and visible light. The photoinduced crystal bending can be repeated over 80 cycles. The rodlike crystal of <b>1a</b> shows different bending behavior depending on the faces irradiated with UV light. This is ascribed to the molecular orientation viewed from the faces. Furthermore, we found that the bending speed depends on the crystal thickness, and the curvature change against the crystal thickness is well-fitted to Timoshenko’s bimetal model. These findings provide a new useful strategy to design for the photomechanical actuators

Crystal Thickness Dependence of Photoinduced Crystal Bending of 1,2-Bis(2-methyl-5-(4-(1-naphthoyl­oxymethyl)­phenyl)-3-thienyl)­perfluoro­cyclo­pentene

The photoinduced crystal bending of a photochromic diaryl­ethene derivative, 1,2-bis­(2-methyl-5-(4-(1-naphthoyl­oxymethyl)­phenyl)-3-thienyl)­perfluoro­cyclo­pentene (<b>1a</b>), has been particularly investigated. The rodlike crystal of <b>1a</b> shows reversible photoinduced bending upon alternating irradiation with ultraviolet (UV) and visible light. The photoinduced crystal bending can be repeated over 80 cycles. The rodlike crystal of <b>1a</b> shows different bending behavior depending on the faces irradiated with UV light. This is ascribed to the molecular orientation viewed from the faces. Furthermore, we found that the bending speed depends on the crystal thickness, and the curvature change against the crystal thickness is well-fitted to Timoshenko’s bimetal model. These findings provide a new useful strategy to design for the photomechanical actuators