- Synthesis of tetrathiafluvalene derivatives with photochromic diarylethene moieties
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Tetrathiafulvalene (TTF) derivatives with diarylethene moieties have been synthesized. A derivative having 2,4,5-trimethylthiophene rings as the aryl groups showed photochromism, while a derivative with 2,5-dimethylthiophene rings did not show any color change by UV irradiation. The different reactivity was ascribed to the difference in the conformation of thiophene rings in the two derivatives.
- Uchida, Kingo,Masuda, Go,Aoi, Yoshifumi,Nakayama, Koji,Irie, Masahiro
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- Synthesis and properties of dihetaryl-substituted furanones. Synthesis of photochromic dithienylethenes containing a furanone bridging fragment
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The reaction of 2,5-dimethylthiophen-3-ylacetic acid with 2,5-dimethylthiophen-3-ylacetyl chloride gave 3,4-bis(2,5-dimethylthiophen-3-yl) furan-2(5H)-one which was converted into a series of 5-methylidene and 5-arylmethylidene derivatives.
- Krayushkin,Pashchenko,Lichitskii,Valova,Strokach,Barachevskii
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- Electronic Asymmetry of an Annelated Pyridyl-Mesoionic Carbene Scaffold: Application in Pd(II)-Catalyzed Wacker-Type Oxidation of Olefins
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The two donor modules of an annelated pyridyl-mesoionic carbene ligand (aPmic) have different σ- and π-bonding characteristics leading to its electronic asymmetry. A Pd(II) complex 1 featuring aPmic catalyzes the oxidation of a wide range of terminal olefins to the corresponding methyl ketones in good to excellent yields in acetonitrile. The catalytic reaction is proposed to proceed via syn-peroxypalladation and a subsequent rate-limiting 1,2-hydride shift, which is supported by kinetic studies. The electronic asymmetry of aPmic renders a well-defined coordination sphere at Pd. The favored arrangement of reactants on the metal center features an olefin trans to the pyridyl module and a tbutylperoxide trans to the carbene. This arrangement gains added stability by the π-delocalization paved by the compatible orbitals on Pd, the pyridyl module, and the olefin that is perpendicular to the Pd(aPmic) plane. The π-interactions are absent in an alternate arrangement wherein the olefin is trans to the carbene. Density functional theory studies reveal the matching orbital overlaps responsible for the preferred arrangement over the other. This work provides an orbital description for the electronic asymmetry of aPmic.
- Bera, Jitendra K.,Dutta, Indranil,Kunnikuruvan, Sooraj,Reshi, Noor U Din,Saha, Sayantani,Yadav, Suman
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p. 11385 - 11393
(2020/11/23)
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- Switchable slow relaxation of magnetization in photochromic dysprosium(III) complexes manipulated by a dithienylethene ligand
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The photochromic and magnetic properties of two dithienylethene (DTE)-based complexes, [Dy(NO3)3(Lo)2(MeOH)] (1-o) and [Dy(NO3)3(Lo)3] (2-o) (Lo = 4,5-bis(2,5-dimethylthiophen-3-yl)-1,3-dimethyl-1,3-dihydro-2H-imidazol-2-one), were experimentally studied in detail with the help of theoretical calculations. Both complexes exhibit an instantaneous and strong reversible photochromic response to UV/Vis irradiation, as evidenced from spectroscopic tests, and complex 1-o behaves as a typical field-induced single-molecule magnet (SMM). By controlling the reaction ratio of Lo and Dy(NO)3, Lo replacing a coordinated methanol molecule in 1-o results in the production of complex 2-o, whose single-molecule behavior is off. Upon irradiation with 254 nm light, the SMM properties of 1-o deteriorate with the energy barrier decreasing from 68.1 to 44.3 K while the magnetic dynamics of complex 2-o shows no response to irradiation. Ab initio calculations reveal that the quantum tunnelling of magnetization between the ground Kramers doublets in 2-o is quite strong, leading to the disappearance of SMM behavior. For complex 1-o, the strong magnetic anisotropy and moderate quantum tunnelling of magnetization relative to 2-o give rise to an appropriate energy barrier for SMM. On the other hand, the decrease in energy barriers for 1-o after irradiation results from the weakening of magnetic anisotropy, which is caused by the stronger charge delocalization of the coordinated carbonyl oxygen atom of the ring-closed DTE ligand. By regulating the reactant ratio, two photochromic DTE-based Dy(III) complexes are obtained and the SMM properties of complex 1-o can be tuned by the light-induced isomerization of the dithienylethene ligand. This journal is
- Kong, Ming,Feng, Xin,Li, Jing,Wang, Jia,Zhang, Yi-Quan,Song, You
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supporting information
p. 20129 - 20136
(2020/12/21)
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- Electrochromic properties of novel chalcones containing triphenylamine moiety
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A series of novel electrochromic chalcones containing triphenylamine units were synthesized by Aldol reaction and characterized by NMR, IR and MS. Their optical, electrochemical properties were investigated using UV-vis, photoluminescence spectra and cyclic voltammetry. The molecular orbital energy levels and excitation energies were calculated by quantum chemical calculation. It was found that the fluorescence intensity is decreasing with formation of charge-transfer state. The existence of electron donating group on triphenylamine unites caused a significant bathochromic shift of the UV absorption maximum and increased EHOMO and ELUMO. The electrochromic property of the synthesized compounds was studied by spectroelectrochemical experiments. The results showed that the chalcones containing triphenylamine moiety presented good electrochromic stability, with a color change from yellow to blue as applied potentials ranging from 0.0 to 2.8 V. The coloring and bleaching time was in the range of 2.9-4.2 s and 1.7-3.3 s, respectively.
- Jin, Huiyi,Li, Xianggao,Tan, Tingfeng,Wang, Shirong,Xiao, Yin,Tian, Jianhua
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p. 154 - 160
(2014/04/17)
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- Synthesis of photochromic bisfulgimides by the condensation of (3Z)-3-[1-(2,5-dimethyl-3-thienyl)-ethylidene]-4-isopropylidene-2,5-furandione with aromatic diamines
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The first representatives of thiophene derivatives with two fulgimide fragments in one molecule have been obtained by the condensation of (3Z)-3-[1-(2,5-dimethyl-3-thienyl)ethylidene]-4-isopropylidene-2,5-furandione with aromatic diamines. The photochromic properties of the obtained compounds have been investigated and the effect of a spacer, linking the two fulgimide fragments, on the reaction rates of photocoloration and photodecoloration of these compounds has been studied.
- Luyksaar,Krayushkin,Pyankov,Barachevsky
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scheme or table
p. 822 - 828
(2011/07/29)
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- Single-crystalline photochromism of diarylethene dimers bridged by a spiro structure
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New types of diarylethene dimers bridged by a spiro structure were synthesized. One of their dimers formed three kinds of polymorphic forms by recrystallization from different solvents: hexane (1a-α), acetone (1a-β), and acetonitrile (la-γ). In crystals of 1a-α and 1a-β the molecules are packed in solvent-free crystal structures, whereas crystal 1a-γ includes acetonitrile molecules in the crystal. The difference of significant photochromic reactivities in their polymorphic crystals was observed for photocoloration reactions. Crystals 1a-β and 1a-γ showed photochromism in the single-crystal phase, but 1a-α did not do so. Their photochromic reactivity was found to depend on the distance between the reactive carbon atoms by X-ray crystallographic analysis. When the distance is less than 4.2 A in the antiparallel conformation, the molecule can undergo photochromism in the crystal. On the other hand, crystals of bromo-substituted diarylethene dimer (2a) cannot be suitable for X-ray crystallographic analysis when it was recrystallized from hexane, acetone, and acetonitrile. However, it formed single crystal by recrystallization from p-xylene, which showed photochromism in the crystalline phase. The edge-to-face aromatic interaction between p-xylene molecules assisted the crystal growth of the diarylethene dimer. Upon irradiation with ultraviolet light, two kinds of the enantiomers, (M,SS)- and (P,RR)-2b, are produced. Partial photobleaching reactions of either of the two enantiomers by irradiation with linearly polarized visible light were confirmed by polarized absorption spectroscopy. Copyright
- Kobatake, Seiya,Kuma, Shunpei,Irie, Masahiro
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p. 960 - 967
(2008/04/13)
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- Study on photochromism of diarylethenes with a 2,5-dihydropyrrole bridging unit: A convenient preparation of 3,4-diarylpyrroles from 3,4-diaryl-2,5- dihydropyrroles
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Symmetric and nonsymmetric diarylethenes with a 2,5-dihydropyrrole bridging unit have been prepared, and the photochromic properties are investigated. Both symmetric and nonsymmetric diarylethenes with 2,5-dihydropyrrole bridging units undergo reversible ring-opening and ring-closing photoisomerization reactions in nonpolar solvents with UV/vis light, and some of them exhibit good fatigue resistance and no marked degradation detected after 10 cycles via an on/off switch. In polar solvents, however, photochromic diarylethenes with 2,5-dihydropyrrole bridging units produce 3,4-diarylpyrrole derivatives instead of the ring-closing isomer of diarylethenes with UV light irradiation. A class of N-substituted 3,4-diphenylethenes with 2,5-dihydropyrrole bridging units were prepared and used as templates to investigate the conversion reactions. The mechanism of photoconversion of 3,4-diaryl-2,5-dihydropyrroles to 3,4-diarylpyrroles was explored as well.
- Chen, Yi,Zeng, De X.,Xie, Nan,Dang, Yi Z.
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p. 5001 - 5005
(2007/10/03)
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- Photochromic Heterocyclic Fulgides. Part 4. The Thermal and Photochemical Reactions of (E)-Isopropylidene -succinic Anhydrides and Related Compounds
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The pale yellow (E)-2--3-isopropylidenesuccinic anhydride undergoes a reversible photochemical reaction to give, in quantitative yield, the deep red 2,4,7,7,7a-pentamethyl-7,7a-dihydrobenzothiophene-5,6-dicarboxylic anhydride, which is stable at 100 deg C.The corresponding (E)-(2,5-dimethyl-3-thienylmethylene) compound does not photocyclise but shows only E-Z photoisomerisation. 2- and 3-Thienyl compounds, lacking a 3- or 2-methyl substituent, respectively, undergo photochemical and/or thermal ring-closure followed by 1,3- and/or 1,5-hydrogen shifts, depending on the reaction conditions.
- Glaze, Alan P.,Harris, Stuart A.,Heller, Harry G.,Johncock, William,Oliver, Stephen N.,et al.
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p. 957 - 962
(2007/10/02)
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