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

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

Polymorphic Crystallization and Thermodynamic Phase Transition between the Polymorphs of a Photochromic Diarylethene

We synthesized a photochromic diarylethene, 1,2-bis­(2-methyl-5-(4-hexyloxyphenyl)-3-thienyl)­perfluorocyclopentene (<b>1a</b>), and found that it has two types of crystals, a needle-like α-crystal and a plate-like β-crystal. From X-ray crystallographic analysis, the space groups of the α- and β-crystals were determined to be <i>P</i>1̅ and <i>C</i>2/<i>c</i>, respectively. The molecular conformation and packing of two crystal forms are quite different. The α- and β-crystals can be obtained individually by recrystallization from acetone at different temperatures. The solvent-mediated phase transition from the α-crystal to the β-crystal was found to occur in the acetone solution at room temperature. Moreover, the thermodynamic phase transition from α-form to β-form was found to take place above 88 °C, as confirmed by differential scanning calorimetry measurement, optical microscopic observation under crossed Nicols, and powder X-ray diffraction measurement. The phase transition from α-form to β-form was also observed at 78 °C by photochromic reaction of <b>1a</b>, and the phase transition proceeded from the UV irradiated part to the nonirradiated part

Photoinduced Rapid and Explosive Fragmentation of Diarylethene Crystals Having Urethane Bonding

Photoinduced Rapid and Explosive Fragmentation of Diarylethene Crystals Having Urethane Bondin

Photoinduced Rapid and Explosive Fragmentation of Diarylethene Crystals Having Urethane Bonding

Photoinduced Rapid and Explosive Fragmentation of Diarylethene Crystals Having Urethane Bondin

Mechanical Behavior of Molecular Crystals Induced by Combination of Photochromic Reaction and Reversible Single-Crystal-to-Single-Crystal Phase Transition

We herein report a unique mechanical behavior of a molecular crystal induced by combination of a photochromic reaction and a reversible single-crystal-to-single-crystal (SCSC) phase transition. A crystal of a diarylethene having octyl group at both sides (<b>1a</b>) was found to undergo a reversible thermodynamic SCSC phase transition accompanying a change in crystal length, which was clarified by differential scanning calorimetry measurement, X-ray crystallographic analysis, and direct microscopic observation of the crystal length. Furthermore, upon irradiation with ultraviolet light, the diarylethene crystal exhibited an unusual photomechanical behavior. The mechanism of the behavior was proposed based on photoisomerization of the diarylethene from the open-ring isomer to the closed-ring isomer and a reversible thermodynamic SCSC phase transition, which was well-supported by thermal bending behavior of a photoirradiated crystal

Dependence of Photoinduced Bending Behavior of Diarylethene Crystals on Ultraviolet Irradiation Power

The photoinduced bending behavior of diarylethene crystals upon irradiation with various ultraviolet (UV) light intensities was investigated. The bending velocity of the photoinduced bending crystals was estimated from the curvature of the bending crystal. The initial velocity of curvature change (<i>V</i>_init) increased in proportion to the power of the incident UV light even when the crystal thickness was different, which suggests that the local strain caused by photoisomerization makes a cumulative contribution to the bending behavior. Moreover, for all UV light intensities, the relationship between <i>V</i>_init and the crystal thickness was well explained by the easily handled Timoshenko bimetal model. This result provides a validated method for the quantitative evaluation of the photoinduced bending velocity in various molecular crystals