Fluorescent Photochromic α‐Cyanodiarylethene Molecular Switches: An Emerging and Promising Class of Functional Diarylethene

Abstract

Fluorescent photochromic molecules that exhibit distinct light‐triggered changes in their emission colors are highly desirable for the fabrication of smart soft materials and advanced photonic devices. α‐Cyanodiarylethenes, that is, α‐cyano‐functionalized diarylethenes, as alternative “non‐azo” Z/E photochromic molecular switches, are popular choices due to their unique characteristics such as their aggregation‐induced emission or aggregation‐induced‐enhanced emission behavior in their self‐assembled states, and visible changes in fluorescence colors during Z/E photoisomerization. In recent years, the development of fluorescent photochromic α‐cyanodiarylethene‐based compounds including α‐cyanostilbenes, dicyanodistyrylbenzenes, and diaryldicyanoethenes, has mainly focused on molecular design, photochemical and photophysical behavior in solution, and smart soft matter technologies. In this review, recent significant achievements in light‐responsive systems based on the Z/E photoisomerization of fluorescent photochromic α‐cyanodiarylethene switches that span the range from liquid crystals to gels and finally to self‐assembled nanostructures, are highlighted. The smart soft materials constructed from α‐cyanodiarylethene molecular switches find use in a plethora of areas, including display, sensing, encrypting, actuating, and biomedical imaging applications, among others. The review concludes with a brief perspective on some major challenges and opportunities for the future development of light‐responsive smart soft photonic materials.

Exploring the Electronic Properties of Extended Benzofuran‐Cyanovinyl Derivatives Obtained from Lignocellulosic and Carbohydrate Platforms Raw Materials

“…Cy-Be1 is obtained by [2 + 2] cycloaddition under irradiation at 365 nm between the two cyanovinyl bonds. [48,49,50] The cyclobutane Cy-Be1 is only under a diastereroisomer form with the cyano groups in anti-position. [51] The analysis of the structure demonstrates that the π-dimers of Be1 formed in a head-to-tail orientation presents the adequate approach with a distance d = 3.74 Å between centroids of the cyanovinyl bonds, according with the Schmidt rules to give the specific [2 + 2] cycloaddition.…”

“…After 12 h of irradiation at 365 nm, the resolution of the structure indicates the presence of Be1 and a cyclobutane derivative Cy ‐ Be1 statistically distributed at 55/45 % in the crystal respectively (Figure 7A). Cy ‐ Be1 is obtained by [2+2] cycloaddition under irradiation at 365 nm between the two cyanovinyl bonds [48,49,50] . The cyclobutane Cy ‐ Be1 is only under a diastereroisomer form with the cyano groups in anti‐position [51] .…”

“On-The-Fly” Non-Adiabatic Dynamics Simulations on Photoinduced Ring-Closing Reaction of a Nucleoside-Based Diarylethene Photoswitch

“…Motivated by their wide applications, several photochromic families such as azobenzenes, furylfulgides, spiropyrans, diarylethenes, et cetera, have been developed, in which the azobenzenes and furylfulgides change structures via Z / E isomerization while spiropyrans and diarylethenes transform between their open and closed forms via ring closing and opening reactions [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Among these photochromic families, diarylethenes, usually consisting of two aryl groups linked by a C=C double bond, are considered to be one of the most popular star molecules due to their good photoconversion quantum yield, excellent thermal stability, high fatigue resistance and fast photoresponsivity [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

Photochromic Polyamide 6 Based on Spiropyran Synthesized via Hydrolyzed Ring-Opening Polymerization

“…The research on preparation and application of photochromic materials has attracted extensive attention due to their obvious and rapid color change, being widely applied in optical information storage [ 1 ], chemical sensors [ 2 , 3 ], molecular switches [ 4 ], information security encryption [ 5 ] and smart textiles [ 6 ], etc. Accordingly, various photoswitchable molecules-azobenzenes [ 7 ], spiropyrans [ 8 ], diarylethenes [ 9 ], fulgides [ 10 ] and others [ 11 , 12 ] have been widely investigated and employed for the construction of light-responsive systems and materials.…”