Photoinduced Twisting of a Photochromic Diarylethene Crystal

Abstract

Let's do the twist! Molecular crystals of a diarylethene derivative exhibit photoreversible twisting upon irradiation with UV and visible light. The left‐handed and right‐handed helix formation is ascribed to the contraction of the crystal in a diagonal direction, depending on which face is irradiated with UV light.

Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators

“…888 The twisting and the blue color remain stable in the dark. By irradiation with visible light, the blue color disappears and the twisted crystal relaxes back to the original shape in a few second.…”

Crystal structure of the meta-stable intermediate in the photomechanical, crystal-to-crystal reaction of 9-tert-butyl anthracene ester

“…These materials take advantage of photochemical reactions to convert photon energy directly into mechanical work. [6][7][8][9][10][11][12][13][14][15][16][17][18] In most cases, these dramatic shape changes rely on the formation of a bimorph structure, where interfacial stress between spatially distinct regions of reactant and photoproduct drives the deformation. 1 For example, the cis-trans photoisomerization of azobenzene molecules embedded in liquid crystal polymers can drive dramatic lightinduced bending and curling.…”

Quantitative Evaluation of Photoinduced Bending Speed of Diarylethene Crystals

“…The photomechanical crystals have attracted much attention because they can work without any direct contact or electrical wires [9]. Various types of photomechanical behaviors such as contraction [8,10], expansion [11], OPEN ACCESS bending [8,[11][12][13][14][15][16][17], separation [18], twisting [19], and rolling [12] have been reported so far. Although photochromic compounds such as diarylethenes [8,19], furylfulgide [20], azobenzene [21,22], anthracene carboxylates [23][24][25][26][27][28], salicylideneaniline [29], 4-chlorocinnamic acid [30], 1,2-bis(4-pyridyl)ethylene salt [31], benzylidenedimethylimidazolinone [32], and others [33] exhibit photochemical reactions in the crystalline phase, their photomechanical motions in the crystal are almost bending.…”