Benzo[b]Germole-Fused Diarylethenes as Photochromic Organogermanium Compounds

Abstract

The molecular design of various heterocycles incorporated into photochromic diarylethenes plays an important role in diversifying functionality. Herein, we report the design, synthesis, and structural characterization of photochromic benzo[b]germole-fused diarylethenes. Photochromic behaviors including clean conversion between the open and the photogenerated closed forms under ambient conditions over multiple photoswitching cycles with insignificant loss of photochemical reactivity, thermal irreversibility with negligible backward reaction of the photogenerated closed form back to the open form even at 100 °C, and satisfactory and comparable photochromic quantum yields for the forward and backward photoswitching processes are observed. This work demonstrates the employment of a rarely explored germole ring with weak aromaticity as a versatile building block for the ethene bridge of the photochromic diarylethene, which is the first of its kind to construct photochromic materials for potential applications, further expanding the diversity of the heterocycle-fused diarylethene-based system with interesting photocontrolled functions.

Beyond Color Boundaries: Pioneering Developments in Cholesteric Liquid Crystal Photonic Actuators

“…Azobenzene provides the potential for pattern memorization in its response to light and heat, while the photoisomerization effect enables patterns to be erased and rewritten repeatedly, presenting novel possibilities for the utilization of photonic materials. [ [160][161][162] azobenzene The cis-trans isomerism formed by -N=N- [163][164][165][166][167][168] spirooxazine Two orthogonal planes connected by a spiral carbon atom as the center rotates under ultraviolet light [173,174] naphthopyran C-O bond breaks and opens the ring, extending the planar and conjugated structure [175,176] Designs utilizing azobenzene and its derivatives can be combined to achieve sophisticated light control designs. Lang Qin et al introduced intricate patterns comprising three primary red, green, and blue (RGB) colors against a black background, achieved through the segmented reflection tuning of CLCs using a newly developed photoresponsive tristable chiral switch [177].…”

“…This remarkable reaction enables CLCs to become photo-tunable. Several photoisomerized substances, including spiropyran [ 156 , 157 , 158 , 159 ], diarylethenes [ 160 , 161 , 162 ], and azobenzene [ 163 , 164 , 165 , 166 , 167 , 168 ], have been reported to undergo reversible changes in geometry. Table 2 describes a selection of commonly used photoisomer substances.…”