Synthesis of photochromic 3,4-bis(1,2-dimethylindol-3-yl)-2,5-dihydrothiophene

Rybalkin, V. P.; Шепеленко, Е. Н.; Попова, Л. Л.; Дубоносов, А. Д.; Метелица, А. В.; Макарова, Н. И.; Breń, V. A.

doi:10.1134/s1070428006040257

Cited by 4 publications

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“…More than 2000 papers focused on this group of molecular switches have been published, and this is indicative of the importance of these compounds in current scientific research. Hundreds of derivatives from those photochromic molecules have been studied so far: symmetrically and nonsymmetrically substituted ones, with different aromatic rings instead of thiophene, with different cycloalkene sizes connecting both terminal aromatic rings, and with different organic and organometallic substituents . Their reversible photoswitching behavior has been studied not only in solution but also in the crystalline state, as liquid crystals, and even as gels …”

Section: Introductionmentioning

confidence: 99%

Limits of Molecular Dithienylethene Switches Caused by Ferrocenyl Substitution

et al. 2016

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The efficiency of photochromic switches can be modified by attaching organic or organometallic groups to the photochromic core. We studied ferrocene-substituted dithienylethene switches differing by the size of the cycloalkene ring bridging the two thiophene groups. The results were compared with their chlorine-substituted counterparts and an ethynyl-ferrocene substituted switch published earlier by Guirado and co-workers. From the measured UV/Vis spectra, both ferrocene-substituted compounds were found to be considerably less likely to switch than the corresponding chlorine-substituted ones. Kohn-Sham density functional theory calculations suggested that this is due to a multitude of energetically close-lying excited states in the former, which may offer multiple pathways for excitation and relaxation, out of which only one leads to ring opening or closing. By contrast, the chlorine-substituted switches have one energetically more isolated state that is responsible for the switching. The increase in the available excited states in the ferrocene-substituted switches was attributed to mixing between orbitals from the ferrocene units and the π system of the bridge.

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Section: Introductionmentioning

confidence: 99%

Limits of Molecular Dithienylethene Switches Caused by Ferrocenyl Substitution

et al. 2016

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“…In the last three decades, hundreds of derivatives of those photochromic systems have been published: symmetrically and nonsymmetrically substituted ones, with different aromatic rings connected by cycloalkenes of different sizes and different organic and organometallic substituents . Their reversible photoswitching behaviour has been studied in solution, in the crystalline state, in liquid‐crystals and as gel .…”

Section: Introductionmentioning

confidence: 99%

Why Are Dithienylethene‐Linked Biscobaltocenes so Hard to Photoswitch?

et al. 2017

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Attaching an organometallic unit to a dithienylethene (DTE) molecular switch can allow one to vary its switching and spectroscopic properties, and to create switchable magnetic properties. In this work, two different dithienylethene molecular switches are used as a bridge between two cobalt sandwich units. The only difference between the switching cores is in the size of the cycloalkene ring connecting both thiophene rings. The complexes present different oxidation states for the cobalt atoms, which are demonstrated to determine the switching reaction. The UV/Vis measurements show that while the Co(I) complexes undergo the switching reaction, the Co(II,III) complexes switch poorly. Kohn-Sham density functional theory calculations indicate diabatic ring-closure mechanisms and a large number of excited states hindering the cyclization reaction and favoring the relaxation to the open form of the molecular switch.

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The McMurry Coupling and Related Reactions

Takeda

Tsubouchi

2013

Organic Reactions

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The McMurry coupling reaction has been recognized as one of the most efficient methods for the synthesis of alkenes from carbonyl compounds. This reaction can be applied to the preparation of various alkenes that are otherwise difficult to prepare. For example, sterically congested tetrasubstituted alkenes as well as medium to large membered rings involving natural products may be accessed via this process. This coupling utilizes various low‐valent titanium reagents generated by the reduction of titanium (III or IV) chloride with K, Zn, LiAlH 4 , C 8 K, amongst others. Furthermore, a variety of low‐valent metal species other than titanium, including aluminum, zirconium, niobium, molybdenum, indium, tungsten, and samarium, have also been found to promote the reductive coupling of carbonyl compounds. The scope and limitations of these reagent systems are reviewed in this chapter, together with the stereochemistry and reaction mechanism. This reaction is categorized into four coupling modes: i) homocoupling giving symmetrical alkenes, ii) mixed coupling giving unsymmetrical alkenes, iii) intramolecular coupling giving cycloalkenes, and iv) tandem coupling giving cyclic polyenes. Characteristics of these reaction modes are described briefly. A selection of synthetic applications are reviewed, including examples of the preparation of sterically congested and strained alkenes, medium to large‐ring compounds, biologically active targets, as well as substrates applicable in material science. Experimental conditions used for this versatile process are summarized to assist the choice of suitable conditions.

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Synthesis of photochromic 3,4-bis(1,2-dimethylindol-3-yl)-2,5-dihydrothiophene

Cited by 4 publications

References 4 publications

Limits of Molecular Dithienylethene Switches Caused by Ferrocenyl Substitution

Limits of Molecular Dithienylethene Switches Caused by Ferrocenyl Substitution

Why Are Dithienylethene‐Linked Biscobaltocenes so Hard to Photoswitch?

The McMurry Coupling and Related Reactions

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