- Emission behavior of a symmetrical sexthiophene
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Detailed absorption and emission behavior were investigated for a sexthiophene molecule in solution, film, and solid. Only strong polarity solvent could result a notable influence on the quench of its fluorescence. In weak and medium polar environment, including in polymer matrix, highly emissive behavior was maintained and exhibit large Stokes shift. More important is its highly emissive in solid state due to the twisted molecular conformation. However, the bandwidth of solid emission (FWHM: 2149 cm?1) is similar to that of solution emission. The calculated frontier orbital based on TDDFT theory uncovered the underlying signal mechanism furtherly.
- Li, Xiaochuan,Zhang, Haiyang,Son, Young-A
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Read Online
- Thiophene Modulated BODIPY Dye as a Light Harvester
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A new BODIPY dye with terthiophene branched is configured by Sonogashira coupling and fully characterized by NMR and MS. In general organic solvents, it emits typical green fluorescence ranging in 513-518 nm, like most BODIPY analogues. The terthiophene substitution is greatly improved and the emission peak does not sensitive to the polarity environment. More importantly, the terthiophene plays the role of antenna, harvesting the 340 nm’s excitation energy and transferring the energy to BODIPY efficiently. Even though the molar extinction coefficient in 340 nm is lower than that of maximum absorption, it can enlarge the pseudo Stoke’s shift to ~170 nm, well separating the excitation and emission. In film, the emission shifted to 562 nm due to the polymer chain dissipation part of the energy. It shifted further to 585 nm in solid. The branched terthiophene configures a twisted molecular conformation, which avoids the dye regular packing. Highly emission, excellent solubility and stability constitute the general character of the thiophene attached BIDIPY dye.
- Li, Xiaochuan,Liao, Meifei,Sun, Jia,Heo, Gisu,Son, Young-A
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p. 127 - 136
(2019/08/20)
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- Environmentally benign indole-catalyzed position-selective halogenation of thioarenes and other aromatics
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Halogenated aromatic compounds are the cores of many pharmaceutical, agricultural and chemical products but they are commonly prepared using electrophilic halogenation reactions in non-green chlorinated solvents under harsh conditions. A separate problem happens in the aromatic halogenation of thioarenes because they readily undergo oxidative side-reactions. Herein we report an environmentally benign electrophilic bromination of aromatics using an indole-catalytic protocol, which is suitable for a wide range of substrates including thioarenes.
- Shi, Yao,Ke, Zhihai,Yeung, Ying-Yeung
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supporting information
p. 4448 - 4452
(2018/10/17)
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- Photoswitchable π-Extended Dithienylethenes with an Attached Molecular Recognition Site
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Photoswitchable dithienylethenes have been extended in positions 5 and 5′ with π-systems resulting in absorptions of light with longer wavelengths when electrocyclization and -reversion are carried out. The extended π-systems also improve conductivities potentially. cis-Orientation of the thienyl rings was accomplished by integrating the central double bond into maleic imides. The nitrogen atoms of the imides were substituted by a Hamilton receptor allowing supramolecular binding of complementary guests such as barbiturates. Both, a stiff and a flexible connection between photoswitch and receptor was realized. The resulting photoswitches showed reversible switching over several cycles and were able to bind diethyl barbiturate with binding constants of > 104 m–1.
- Bittner, Iris,Lüning, Ulrich
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p. 2592 - 2602
(2018/05/14)
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- Synthesis of fungicidally active succinate dehydrogenase inhibitors with novel difluoromethylated heterocyclic acid moieties
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Abstract: Novel fungicidally active succinate dehydrogenase inhibitors have been prepared, which either carry a difluoromethyl and methyl-bearing pyrazoline, pyrrole, or thiophene ring in the acid component, mimicking similar-substituted pyrazole carboxamides. As five-membered heterocyclic systems with such a special substitution pattern are barely known, unique synthesis routes had to be developed, which rely, e.g., on the van Leusen pyrrole synthesis and the halogen dance reaction. Synthesis and biological activity against selected Ascomycete pathogens of these difluoromethylated pyrazoline, pyrrole, and thiophene derivatives are reported.
- Walter, Harald,Lamberth, Clemens,Corsi, Camilla
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p. 791 - 799
(2017/12/11)
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- SUBSTITUTED 1H-IMIDAZO[4,5-B]PYRIDIN-2(3H)-ONES AND THEIR USE AS GLUN2B RECEPTOR MODULATORS
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Substituted 1 H-imidazo[4,5-b]pyridin-2(3H)-ones as NR2B receptor ligands. Such compounds may be used in NR2B receptor modulation and in pharmaceutical compositions and methods for the treatment of disease states, disorders, and conditions mediated by NR2B receptor activity.
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Page/Page column 134
(2018/04/23)
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- A BODIPY-based highly emissive dye with thiophene-based branch harvesting the light
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A novel BODIPY-based dye with highly emissive character was configured by Sonogashira coupling and routinely characterized by NMR and MS technology. The emission of dye was investigated in solution/film/solid and shows intensive emission. In solution, the emission peak appeared around 510?nm with little influence by the polar environment. The terthiophene plays an effective antenna effect, harvesting the light and transferring the energy to BODIPY. The pseudo Stoke's shift enlarged to ~170?nm in solution. In film, the emission peak shifted to 563?nm in polycarbonate matrix. And it shifted further to 585?nm in solid due to the highly twisted structure, which avoided closely regular-tight packing. The dye rendered an intense fluorescence, good optothermal stability, and high fluorescence quantum yield (0.55). The solid emission showed highly red emission with Commission Internationale de L'Eclairage (CIE) coordinates of (X = 0.69, Y = 0.31). Thus, the synthesized dye is idea candidate for emitting materials.
- Li, Xiaochuan,Han, Yujie,Kim, Myeong Jin,Son, Young-A
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p. 157 - 164
(2018/06/11)
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- Design, syntheses and photochromic properties of dithienylcyclopentene optical molecular switches
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A kind of basal diarylethene through an easy synthetic procedure was synthesized and characterized, and a Suzuki coupling reaction was frequently operated to obtain the diarylethenes derivatives with some vivid functional groups like bromo, amido and pyridine. Two methods for derivatives of these switches contain porphyrins were described. All of their spectroscopic and photochromic properties were studied and intercompared. It is indicated that the difference in electron densities of the π-conjugated system of the closed forms has effects upon the absorption maxima in visible region of UV–Vis spectra. Dithienylcyclopentenes linked to porphyrins could emit luminescence substantially that display potentials to be used in the applications of nondestructive readout upon binary data storage and smart materials.
- Yu, Chuanming,Hu, Bingcheng,Liu, Cheng,Li, Jiting
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- Functionalization of photochromic dithienylmaleimides
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Photochromic dithienylmaleimides are well known molecular switches, but for applications the suitable functionalization of the photochromic scaffold is required. We report here synthetic routes to dithienylmaleimides, which are functionalized at three different positions: at each of the thiophene moieties and the maleimide nitrogen. A Perkin-type condensation of two thiophene precursors is used as the key step to assemble the maleimide core, which allows the synthesis of non-symmetrically substituted dithienylmaleimides, such as photochromic amino acids. A different approach to the maleimide core is provided by the reaction of a dithienylmaleic anhydride with amines or hydrazides leading to maleimide protected dithienylmaleimides and photochromic labeled natural amino acids. The photochromic properties of the new photoswitches were investigated showing reversible photochromism in polar organic solvents. This journal is
- Wutz,Falenczyk,Kuzmanovic,K?nig
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p. 18075 - 18086
(2015/03/04)
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- π-complexation in nickel-catalyzed cross-coupling reactions
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The kinetic isotope effect (KIE) is used to experimentally elucidate the first irreversible step in oxidative addition reactions of a zerovalent nickel catalyst to a set of haloarene substrates. Halogenated o-methylbenzene, dimethoxybenzene, and thiophene derivatives undergo intramolecular oxidative addition through irreversible π-complexation. Density functional theory computations at the B3LYP-D3/TZ2P-LANL2TZ(f)-LANL08d level predict η2-bound π-complexes are generally stable relative to a solvated catalyst plus free substrate and that ring-walking of the Ni(0) catalyst and intramolecular oxidative addition are facile in these intermediates.
- Sontag, S. Kyle,Bilbrey, Jenna A.,Huddleston, N. Eric,Sheppard, Gareth R.,Allen, Wesley D.,Locklin, Jason
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p. 1836 - 1841
(2014/03/21)
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- Fused H-shaped tetrathiafulvalene-oligothiophenes as charge transport materials for OFETs and OPVs
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A series of hybrid tetrathiafulvalene-oligothiophene compounds has been synthesised, where the tetrathiafulvalene unit is fused at each side to an end-capped oligothiophene chain of varying length (terthiophene, quinquithiophene and septithiophene). Each hybrid structure (1-3) has been studied by cyclic voltammetry and triple EPR-UV-Vis-NIR spectroelectrochemistry in the case of the quinquithiophene compound (2). Comparison is made with the corresponding half-units, which lack the fulvalene core and contain just one oligothiophene chain. The highest hole mobility of quinquithiophene-TTF 2 was obtained from field effect transistors (8.61 × 10-3 cm 2 V-1 s-1); its surface morphology was characterised by tapping mode atomic force microscopy and a power conversion of 2.5% was achieved from a bulk heterojunction organic solar cell device using PC71BM as the acceptor. This journal is the Partner Organisations 2014.
- Wright, Iain A.,Findlay, Neil J.,Arumugam, Sasikumar,Inigo, Anto R.,Kanibolotsky, Alexander L.,Zassowski, Pawel,Domagala, Wojciech,Skabara, Peter J.
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p. 2674 - 2683
(2014/04/03)
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- Synthesis, characterization, and properties of some bisacetylide and binuclear acetylide gold(I) compounds based on the photochromic dithienylethene unit
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We report the synthesis and characterization of two new bisacetylide compounds, 1,2-bis(2-ethynyl-5-methyl-3-thienyl)perfluorocyclopentene and 1-[2-methyl-5-phenyl-3-thienyl]-2-[4-methyl-2,5-bis(ethynyl)-3-thienyl] hexafluorocyclopentene together with three dinuclear acetylide gold(I) complexes LAu-CC-dithienylethene-CC-AuL in which L = PPh3 or PCy3, containing the photochromic dithienylethene unit. The photophysical properties of these new complexes are compared and contrasted with those of some previously reported dithienylethene complexes. It has been revealed that these compounds with dithienyletehene units show photochromic behavior, but their absorption spectra, cyclization/cycloreversion quantum yields, and efficiencies of the photochromic process and conversions from the open- to the closed-ring isomers in the photostationary state, are all highly dependent on the substitution sites of the bisalkynyl moiety and whether or not there is bisalkyne metalation. The photochromic process was also found to show complete reversibility by alternating irradiation with UV and visible light.
- Lin, Yan,Jiang, Chuanyin,Hu, Fang,Yin, Jun,Yu, Guang-Ao,Liu, Sheng Hua
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p. 995 - 1003
(2013/09/23)
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- An efficient and regioselective monobromination of electron-rich aromatic compounds using catalytic hypervalent iodine(III) reagent
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An efficient and regioselective monobromination of electron-rich aromatic compounds is reported in which iodobenzene is used as the recyclable catalyst in combination with m-chloroperbenzoic acid as the terminal oxidant. The bromination of electron-rich aromatic compounds with lithium bromide was fast in tetrahydrofuran at room temperature, providing regioselective monobrominated products in good yields.
- Zhou, Zhongshi,He, Xuehan
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experimental part
p. 207 - 209
(2011/03/18)
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- Synthesis of photochromic compounds for aqueous solutions and focusable light
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Photochromic compounds with improved performance in pure water have been prepared and characterized. They possess an asymmetrical and extended conjugation system with a 1,2-bis(3-thienyl)perfluorocyclopentene core, additional thiophene rings connected with sulfonic acid residues, as well as terminal pyrid-4-yl and 4-alkoxyphenyl groups. A multistep synthetic route to a key compound with an amino group required for further derivatization has been developed. The complete photocyclization reaction of the initial "open ring" compound (with absorption maximum at 340 nm in MeOH or water) can be performed with a diode laser in pure water or aqueous buffer solutions (without added or-ganic solvents) under irradiation at 366-375 nm, and the reverse ring-opening reaction of the colored "closed ring" compound (λmax = 628 or 624 nm in MeOH or water) takes place under irradiation with visible green or red light (>500 nm). Building block 57, with a secondary amino group, can further be used in the synthesis of practically important, reversibly switchable, fluorescent compounds in which the fluorescent dye (donor) is attached to a photochromic unit (acceptor), and the resonant energy transfer from a donor to the colored form of an acceptor provides a reversible quenching of the fluorescence signal in aqueous solutions.
- Polyakova, Svetlana M.,Belov, Vladimir N.,Bossi, Mariano L.,Hell, Stefan W.
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scheme or table
p. 3301 - 3312
(2011/08/03)
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- Brominated thiophenes as precursors in the preparation of brominated and arylated anthraquinones
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Brominated anthraquinones can be synthesized directly from bromothiophenes when these are reacted with 1,4-naphthoquinones in the presence of meta-chloroperoxybenzoic acid. The bromoanthraquinones are versatile building blocks in the preparation of arylated anthraquinones and of extended π-systems with interspersed anthraquinone units.
- Thiemann, Thies,Tanaka, Yasuko,Iniesta, Jesus
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experimental part
p. 1013 - 1031
(2009/10/10)
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- Sterics versus electronics: Regioselective cross-coupling of polybrominated thiophenes
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Methods for the regioselective cross-coupling of 2,3,5-tribromothiophene have been developed in which selective aryl-aryl coupling occurs at the 5-position with yields up to 63%. The difference in reactivity of the α- and β-positions then allows sequential regioselective couplings first at the 2-position, followed by the 3-position. Such regioselective cross-coupling allows unprecedented control in the generation of trifunctionalized thiophenes. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Amb, Chad M.,Rasmussen, Seth C.
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supporting information; experimental part
p. 801 - 804
(2009/04/11)
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- Tunable luminescence of new photochromic bisthienylethenes containing triphenylamine
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Two new photochromic 1,2-bisthienylethenes containing triphenylamine were conveniently prepared; large cyclization quantum yields and obvious fluorescent changes regulated by the photoisomerization were observed. The substitution effect on the photochromic process is discussed based on these systems. CSIRO 2005.
- Luo, Qianfu,Sheng, Saihong,Cheng, Saihe,Tian, He
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p. 321 - 326
(2007/10/03)
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- (Diacetoxyiodo)benzene-Lithium Bromide as a Convenient Electrophilic Br+ Source
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A mild and versatile procedure for the bromination of olefins and activated arenes by in situ generation of 'Br+' using (diacetoxyiodo)benzene and lithium bromide is presented. The reactions were carried out in open vessels at room temperature and were typically complete in 30 minutes. The brominated products were isolated by column chromatography, which also allowed for the isolation of the iodobenzene by-product for recycle.
- Braddock, D. Christopher,Cansell, Gemma,Hermitage, Stephen A.
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p. 461 - 464
(2007/10/03)
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- Expanding tetra[2,3-thienylene]-based molecular muscles to larger [4n]annulenes
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The synthesis, X-ray structure, and predicted redox-induced conformational dynamics of a thiophene-fused [12]annulene is reported. Regiospecific halogenation of the thiophene ring system and transition-metal catalyzed cross-couplings are key elements in the synthetic strategy. It is predicted (B3LYP/6-31G*) that redox-induced conformational changes yield significant dimensional changes in this annulene, thus establishing it as a candidate for single molecule actuation.
- Marsella, Michael J.,Piao, Guangzhe,Tham, Fook S.
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p. 1133 - 1135
(2007/10/03)
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- Novel, potent non-covalent thrombin inhibitors incorporating P3-lactam scaffolds
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Evolution of P1-argininal inhibitor prototypes led to a series of non-covalent P3-7-membered lactam inhibitors 1a-w, featuring novel peptidomimetic units that probe each of the S1, S2, and S3 specificity pockets of thrombin. Rigid P1-arginine surrogates possessing a wide range of basicity (calcd pKa's~neutral-14) were surveyed. The design, synthesis, and biological activity of these targets are presented.
- Ho, Jonathan Z.,Gibson, Tony S.,Semple
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p. 743 - 748
(2007/10/03)
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- Nematic 2,5-disubstituted thiophenes
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A large number of new liquid crystals incorporating the 2,5-disubstituted thiophene ring have been prepared and their mesomorphic behaviour studied in order to systematically investigate the correlation between the molecular structure and mesomorphism of thiophene derivatives with different shapes, polarisability and polarity. As a consequence of these investigations we have prepared a new class of liquid crystals incorporating a 2,5-disubstituted thiophene ring and a conjugated trans-carbon-carbon double bond in the terminal chain. These novel thiophene derivatives are the first liquid crystals incorporating a 2,5-disubstituted thiophene ring to exhibit a nematic phase at room temperature. This enables the flexoelectric coefficients of a bent-shaped molecule to be measured directly and at room temperature for the first time to the authors' knowledge. Many of these new thiophenes exhibit a high birefringence and a high nematic clearing point and are of potential use as components of nematic mixtures in LCDs.
- Campbell, Neil L.,Duffy, Warren L.,Thomas, Gareth I.,Wild, Janine H.,Kelly, Stephen M.,Bartle, Kevin,O'Neill, Mary,Minter, Vicky,Tuffin, Rachel P.
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p. 2706 - 2721
(2007/10/03)
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- Nematic thiophenes for STN-LCDS and flexoelectric LCDS
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We report anew class of liquid crystals incorporating a 2,5-disubstituted thiophene ring and one or two conjugated trans-carbon-carbon double bonds in the terminal chain for use as components of nematic mixtures for TN-LCDs and STN-LCDs. The combination of these molecular elements contribute towards generating a high birefringence, a high nematic clearing point as well as a low viscosity for these materials. Several of these compounds exhibit a melting point below room temperature. This is the first time a room temperature nematic phase has been reported for phenyl thiophene derivatives. The new thiophene compounds can be used to induce a high birefringence in nematic mixtures for LCDs with short response times.
- Bartle, Kevin,Campbell, Neil,Duffy, Warren L.,Kelly, Stephen M.,Minter, Vicki,O'Neill, Mary,Tuffin, Rachel P.
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p. 881 - 888
(2007/10/03)
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- Biphasic Electrophilic Halogenation of Activated Aromatics and Heteroaromatics with N-Halosuccinimides Catalyzed by Perchloric Acid
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Catalytic amounts of 70percent perchloric acid (0.1 - 10, mostly 0.1 - 1, mol percent, based on substrate) initiate the regioselective halogenation of activated aromatics and heteroaromatics with N-halosuccinimide (NXS, X = Cl or Br) in two-phase solid-liquid systems (NXS/hexane or NXS/CCl4) at room temperature to give ring-halogenated products in high yields.For example, thiophene is transformed to 2-halo or 2,5-dihalo derivatives (yield 82-98percent) using 1 or 2 equiv of NXS, respectively.Unsymmetrical 2,5-dihalothiophenes are obtained in 70-82percent yield by reacting 2-halothiophenes with an appropriate NXS.The reaction of 3-bromothiophene with NBS affords 2,3-dibromothiophene in 93-99percent yield. 1,3-Dimethoxybenzene and 2,3-dimethylanisole are halogenated regiospecifically at the 4-position to give the corresponding products in 81-94percent yield.
- Goldberg, Yuri,Alper, Howard
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p. 3072 - 3075
(2007/10/02)
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- A simple and improved procedure for selective ring bromination of alkyl-substituted aromatic hydrocarbons on the surface of alumina
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Highly selective ring bromination of alkyl-substituted aromatic hydrocarbons has been achieved using molecular bromine adsorbed on the surface of alumina without any solvent.
- Ranu,Sarkar,Chakraborty
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p. 1095 - 1099
(2007/10/02)
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- NOVEL HALOGENATION OF THIOPHENES WITH BENZENESELENINYL CHLORIDE AND ALUMINUM HALIDE
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In the presence of aluminum halide, benzeneseleninyl chloride is an efficient regioselective halogenating reagent for heterocyclic compounds such as thiophene, 2-methylthiophene, 3-methylthiophene, 2,5-dimethylthiophene, and furan.In the case of pyrrole, no halogenated product was obtained.A plausible reaction mechanism involving a positive halogen intermediate is proposed.
- Kamigata, Nobumasa,Suzuki, Takashi,Yoshida, Masato
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- Electrophilic Aromatic Substitution. Part 34. Partial Rate Factors for Detritiation of Dithienobenzene, Dithienobenzene, and Dithienobenzene
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Dithienobenzene (I), dithienobenzene (II), and dithienobenzene (III), specifically labelled with tritium in each position, have been synthesized.Their rates of protio-detritiation, in either anhydrous trifluoroacetic acid or mixtures of acetic acid and trifluoroacetic acid, have been measured at 70 deg C.The rate-acidity profiles for each compound show that there is weak hydrogen bonding between sulphur and trifluoroacetic acid, and the extent of this is closely similar to that previously found for thienothiophens thereby confirming the general trend observed with sulphur-containing heterocycles viz. that the extent of hydrogen bonding is proportional to the number of sulphur atoms in the aromatic compounds.Partial rate factors for detritiation, free from the effects of hydrogen bonding, are calculated as follows (position and compound in parentheses): 3.42E6 (1)-(I), 1.65E7 (2)-(I), 5.35E5 (4)-(I), 1.525E7 (2)-(II), 4.98E6 (3)-(II), 1.32E6 (4)-(II), 4.59E5 (5)-(II), 2.35E7 (7)-(II), 4.01E6 (8)-(II), 1.96E7 (2)-(III), 3.77E6 (3)-(III), 3.99E5 (4)-(III); the corresponding ?+ values are -0.745, -0.825, -0.655, -0.82, -0.765, -0.70, -0.645, -0.84, -0.755, -0.835, -0.75, and -0.64.The positional reactivity orders both within a given molecule and between molecules are satisfactorily predicted by localization energies calculated by the simple Hueckel method using the parameters αS 1.0, βCS 0.6, these having been found previously to predict correctly the positional reactivities in other sulphur-containing heterocycles.
- Archer, William J.,Cook, Robert,Taylor, Roger
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p. 813 - 820
(2007/10/02)
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