Photochromic diarylethenes

In some cases, the formation of photochromic maleimides requires drastic conditions. Thus, hybrid meta and ipara derivatives 194 containing both fulgimide and diarylethene photochromic fragments were prepared in 61 and 75%, respectively, by refluxing amines 193 with anhydride 165 in ethanol under argon for 70 h in the presence of molecular sieves (06MI1, llEJO) (Scheme 57). 

The Dithienylethene System and Related Compounds. The area of diaryl-ethenes has been the subjeet of a review.Calculations have been carried out dealing with the photochromism of such compounds.A description of the preparation of diarylethene nanoparticles has been published, and a decrease in photocyclization was attributed to aggregation. Some novel photochromic diarylethenes have been synthesized. The photochemistry exhibited by these compounds suggests that they could be of use as optical switches.Tian and Yang have reviewed the area of diarylethene photochromic switches. 1,2-Bis(2-methylbenzo[b]thiophen-3-yl)hexafluorocyclopentene is at the basis of a new photochromic liquid crystal system. Yokoyama and his co-workers have patented details for such photochromic materials." ... 

Y.C. Jeong, S.I. Yang, E. Kim, K.H. Ahn, A high-content diarylethene photochromic polymer for an efficient fluorescence modulation. Macromol. Rapid Commun. 27, 1769-1773 (2006)... 

C. Bertarelli, A. Bianco, V. Boffa, M. Mirenda, M. C. Gallazzi, G. Zerbi, Poly(dithienylethene-o/i-l,4-divinylenephenylene)s increasing the molecular weights in diarylethene photochromic polymers, Adv. Funct. Mater., 14, 1129-1133 (2004). 

Matsuda, K., Me, M. (2000b). Photoswitching of intramolecular magnetic interaction a diarylethene photochromic spin coupler. Chemistry Letters, 29, 16-17. 

Boggio-Pasqua M, Ravaglia M, Betirpark M, Garavelli M, Robb M (2003) Can diarylethene photochromism be explained by a reaction path alone A CASSCF study with model MMVB dynamics. J Phys Chem A 107 11139... 

Masahiro Irie received his B.S. and M.S. degrees from Kyoto University and his Ph.D. in radiation chemistry from Osaka University. He joined Hokkaido University as a research associate in 1968 and started his research on photochemistry. In 1973 he moved to Osaka University and developed various types of photoresponsive polymers. In 1988 he was appointed Professor at Kyushu University. In the middle of the 1980 s he invented a new class of photochromic molecules - diaryl-ethenes - which undergo thermally irreversible and fatigue resistant photochromic reactions. He is currently interested in developing singlecrystalline photochromism of the diarylethene derivatives. 

Corredor CC, Huang Z, Belfield KD (2006) Two-photon 3D optical data storage via fluorescence modulation of an efficient fluorene dye by a photochromic diarylethene. Adv Mater 18 2910-2914... 

Matsuda K, Yamaguchi H, Sakano T, Ikeda M, Tanifuji N, Irie M (2008) Conductance photoswitching of diarylethene gold nanoparticle network induced by photochromic reaction. J Phys Chem C 112(43) 17005-17010... 

Following similar trials with the formation of diarylbenzenes [63-65], the same research group has reported a multistep synthesis of photochromic diarylethenes using a microflow system that contained two linked micromixers and microreactors (MRi 2) [66]. Similarly to the previously reported linked microreactors, the reactors used in this setup were made of stainless steel tubes and T-shaped micromixers. Initial experiments were conducted in two steps in a continuous sequence to afford symmetrical octasubstitued diaryUiexafluoro cyclopentene (Scheme 29). 

Ushiogi Y, Hase T, linuma Y et al (2007) Synthesis of photochromic diarylethenes using a microflow system. Chem Commun 28 2947-2949... 

The terms diarylethenes, dithienylethenes, and dihetarylethenes, as applied to the structures of photochromic products II, of course, do not strictly meet the nomenclature requirements. However, these terms have gained wide acceptance in the special literature. The classification of compounds containing heterocycles as bridges is also rather arbitrary. 

Recently, the synthesis of photochromic compounds containing two or more diarylethene fragments bound either directly or through linkers has been performed. Scheme 32 illustrates one approach to 96 containing two hexafluorocyclopentene-bridged dihetarylethene fragments (05JACS8922). 

A new class of photochromic diarylethenes containing thieno[3,2-b] thiophenes, dithieno[3,2-b 2, 3 -d]thiophene (08CC5203), and dithieno [3,2-fc 2, 3 -d]pyrroles (09CEJ10005) with photoswitchable luminescence properties were synthesized by Suzuki cross-coupling reactions (Scheme 48). 

Photochromic systems that have been examined in both of these approaches include spiropyrans, spirooxazines, diarylethenes, dihydroindolizines and azoben-zenes. A schematic of a disk structure is shown in Figure 1.14. To produce the... 

Several TTF derivatives with photoresponsive moieties have been described in recent years with a view to studying the interplay of photochromic and electrochemical properties. Uchida, Irie, and coworkers have reported TTF derivatives with diarylethene moieties such as 14.24 The corresponding open- and closed-isomers of 14 can be reversibly interconverted by UV and visible light irradiations. The results show that the open- and closed-isomers of 14 show different electrochemical responses. 

A number of photochromic systems have been extensively investigated that undergo cis-trans isomerization (indigos, azo compounds) cleavage (spiropyrans), electrocyclic processes (fulgides, 1,2-diarylethenes) [8.229, 8.244, 8.245], For instance, cis-trans isomerization of a thio-indigo derivative allows the reading of pyrene excimer or monomer fluorescence [8.246]. The 1,2-dithienylethene system presents particularly attractive interconversion properties by photoreversible cyc-litation [8.245],... 

A diarylethene switch (281-282) that combines excellent photochromic properties with the ability to undergo self-assembly has been reported (05AGE2373). 

Polymer showing photochromic properties was also obtained using oligomers with a diarylethene moiety obtained starting from a benzothio-phene unit, and p-phenylenevinylene (02MM8684). 

Photochromism of Diarylethenes in Confined Reaction Spaces Masahiro Irie... 

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