Synthesis of photochromic derivatives of cyclobutene-1,2-dione

Structural and Spectral Properties of Photochromic Diarylethenes: Size Effect of the Ethene Bridge

“…It was found that a decrease in the size of the ethene bridge leads to a considerable decrease in the cyclization quantum yield (and simultaneously to an increase in the efficiency of the cycloreversion reaction). This effect is more clearly manifested for the dithienyl derivative of cyclobutenedione . This diarylethene, unlike, for example, related derivatives of maleic anhydride, does not exhibit photochromic properties either in solution or in the crystalline phase.…”

“…This effect is more clearly manifested for the dithienyl derivative of cyclobutenedione. 23 This diarylethene, unlike, for example, related derivatives of maleic anhydride, 24 does not exhibit photochromic properties either in solution or in the crystalline phase. However, the photoactivity of diarylethenes based on squaric acid derivatives can be restored by introducing bulky heterocycles, such as thienothiophene 23 or thienypyrrole, 25 instead of thiophene or by modifying the bridge.…”

“…This diarylethene, unlike, for example, related derivatives of maleic anhydride, does not exhibit photochromic properties either in solution or in the crystalline phase. However, the photoactivity of diarylethenes based on squaric acid derivatives can be restored by introducing bulky heterocycles, such as thienothiophene or thienypyrrole, instead of thiophene or by modifying the bridge . Another example of the critical effect of the size of the bridge was described for perfluorocyclohexenone derivatives containing 2-thienyl moieties, which, unlike five-membered analogs, do not exhibit photochromic properties due to steric hindrance between the fluorine atoms of the bridge and the thiophene moieties.…”

Synthesis and characterization of cyclobutenedione–bithiophene π-conjugated polymers: acetal-protecting strategy for Kumada–Tamao–Corriu coupling polymerization between aryl bromide and Grignard reagents

“… 1 Recently, squaric acid bisamides (squaramides) have attracted significant attention and have been used as chemosensors 2 and organocatalysts. 3 The cyclobutenedione unit has been used for pyrolytic and photolytic syntheses of functionalized benzoquinone and phenol 4 as well as cyclo[ n ]carbon, 5 and can serve as a fixed cis -vinylene linker in photochromic derivatives 6 and anticancer agents. 7 …”

Kinetics and mechanism of photochromic transformations of a 2,3-diarylcyclopentenone

“…Recently a new class of photochromic diarylethenes, 2,3 diarylcyclopent 2 en 1 ones (DCPs) was pro posed [11][12][13][14][15][16][17][18][19], which is free of the mentioned disad vantage. In comparison with other diarylethenes, the DCPs have unique abilities to the chemical modifica tion of the cyclopentenone ring.…”