cas 3141-27-3, 2,5-Dibromothiophene | Articles data

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Synthesis of extended α,α'-oligo(silylthiophenes) by cerium(IV) oxidative coupling reactions
Cerium(IV) oxidative dimerisations of 4,4'-bis(trimethylsilyl)-2,2':5',2''-terthiophene and the quaterthienyl analogue 1c gave the corresponding sexi- and octi-thiophenes; the latter have been used to prepare α-linked hexadecithiophene and tetracosithiophene derivatives.
Mustafa, Ali H.,Shepherd, Michael K.
p. 2743 - 2744
(1998)
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Synthesis of bithiophenesilane dendrimer of the first generation
The synthesis of tris{5′-[methylbis(2-thienyl)silyl]2,2′- bithienyl-5-yl} methylsilane, a first-generation bithiophenesilane dendrimer, is described. The conditions of effective formation of methyltrithienylsilane were found; methyltris(5-bromo-2-thienyl)silane and a number of other monofunctional derivatives of methyltrithienylsilane were synthesized for the first time. The advantages and drawbacks of the Suzuki and Kumada reactions for the formation of bithienyl fragments in the synthesis of oligothienylsilane dendrimers are discussed.
Ponomarenko,Muzafarov,Borshchev,Vodopyanov,Demchenko,Myakushev
p. 684 - 690
(2005)
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The influence of an ethynyl spacer on the electronic properties in 2,5-ferrocenyl-substituted heterocycles Dedicated to Prof. Dr. Claude Lapinte for his outstanding contribution to organometallic chemistry especially to electron transfer studies.
A series of binuclear complexes based on five-membered heterocycles featuring alkynyl ferrocenyl groups, 2,5-(FcCC)2-cC4H2E (E = NPh, 3a; S, 3b; O, 3c), has been synthesized using the Sonogashira C,C cross-coupling protocol. The molecular structures of 3a and 3c in the solid state are discussed. The influence of the ethynyl unit on the electronic and (spectro)electrochemical properties of these compounds is shown by cyclic voltammetry (CV), square wave voltammetry (SWV) and in situ UV-Vis-NIR and IR spectroscopy. The high ΔEp values (140-204 mV) of the single reversible redox events indicate that two individual oxidation processes take place in a close potential range. Nevertheless, the NIR measurements indicate weak and broad intervalence charge transfer (IVCT) absorptions for the mixed-valent monocationic species 3a-c+. Compared to 2,5-Fc2-cC4H2E (E = NPh, S, O) the absorptions for the IVCT transitions are shifted hypsochromically, showing that the charge transfer process is promoted at higher excitation energies, due to larger metal-metal distances in 3a-c. The occurrence of IVCT absorptions demonstrates that the 2,5-diethynylferrocenyl heterocycles are class II systems according to Robin and Day.
Pfaff, Ulrike,Hildebrandt, Alexander,Korb, Marcus,Lang, Heinrich
p. 2 - 9
(2015)
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Donor-Acceptor-Donor Thienopyrazine-Based Dyes as NIR-Emitting AIEgens
Organic Near-Infrared luminophores have found broad application as functional materials, but the development of efficient NIR emitters is still a challenging goal. Here we report on a new class of thieno[3,4-b]pyrazine-based NIR emitting materials with Aggregation Induced Emission (AIE) properties. The dyes feature a donor–acceptor–donor (D?A?D) structure, with a thienopyrazine acceptor core connected to two triarylamine donor groups bearing a tetraphenylethylene (TPE) moiety. Fast and efficient synthesis allowed the modular preparation of three dyes of tunable absorption and emission profiles. These constructs were extensively characterized by spectroscopic studies in different solvents, which revealed intense light-harvesting ability and emissions in the deep-red and NIR region with large Stokes shift values. Remarkably, the dyes exhibited AIE properties, retaining emissive ability in the aggregate state, thus emerging as attractive materials for their potential application in the development of luminescent devices.
Calamante, Massimo,Coppola, Carmen,Dessì, Alessio,Franchi, Daniele,Goti, Giulio,Mordini, Alessandro,Reginato, Gianna,Sinicropi, Adalgisa,Zani, Lorenzo
p. 2655 - 2664
(2021/06/26)

Electrochromic properties of pyrene conductive polymers modified by chemical polymerization
Pyrene is composed of four benzene rings and has a unique planar melting ring structure. Pyrene is the smallest condensed polycyclic aromatic hydrocarbon, and its unique structural properties have been extensively studied. Pyrene has excellent properties such as thermal stability, high fluorescence quantum efficiency and high carrier mobility. This paper mainly used thiophene, EDOT and triphenylamine groups to enhance the pyrene based π-conjugated system and control the molecular accumulation of organic semiconductors, and improve their charge transport performances. Five kinds of polymer were synthesized and correspondingly characterized. The five kinds of pyrene conductive polymer had outstanding properties in terms of solubility, fluorescence intensity and thermal stability, good film-forming properties, stable electrochromic properties and high coloring efficiency. The coloration efficiency (CE) of PPYTP was as high as 277 cm2C?1, and the switching response time was short. The coloring time of PPYEDOT was 1.3 s and the bleaching time was 3.2 s. The lower impedance will also provide the possibility of such polymers being incorporated into electrochromic devices in the future. In short, the synthesized new pyrene conductive polymers will have wide application prospects in the field of electrochromic materials.
Chang, Lijing,Hou, Yanjun,Li, Rui,Ma, Yang,Miao, Shoulei,Wang, Cheng,Xu, Haoran,Zhang, Yuhang
p. 39291 - 39305
(2021/12/27)

Role of Substituents at 3-position of Thienylethynyl Spacer on Electronic Properties in Diruthenium(II) Organometallic Wire-like Complexes
A series of organometallic complexes [Cl(dppe)2Ru?C≡C-(3-R?C4H2S)-C≡C?Ru(dppe)2Cl] (3-R-C4H2S=3-substituted thienyl moiety; R=?H, ?C2H5, ?C3H7, ?C4H9, ?C6H13, ?OMe, ?CN in 5 a–5 g respectively) have been synthesized by systematic variation of 3-substituents at the thienylethynyl bridging unit. The diruthenum(II) wire-like complexes (5 a–5 g) have been achieved by the reaction of thienylethynyl bridging units, HC≡C-(3-R-C4H2S)-C≡CH (4 a–4 g) with cis-[Ru(dppe)2Cl2]. The wire-like diruthenium(II) complexes undergo two consecutive electrochemical oxidation processes in the potential range of 0.0 - 0.8 V. Interestingly, the wave separation between the two redox waves is greatly influenced by the substituents at the 3-position of the thienylethynyl. Thus, the substitution on 3-position of the thienylethynyl bridging unit plays a pivotal role for tuning the electronic properties. To understand the electronic behavior, density functional theory (DFT) calculations of the selected diruthenium wire-like complexes (5 a–5 e) with different alkyl appendages are performed. The theoretical data demonstrate that incorporation of alkyl groups to the thienylethynyl entity leaves unsymmetrical spin densities, thus affecting the electronic properties. The voltammetric features of the other two Ru(II) alkynyl complexes 5 f and 5 g (with ?OMe and ?CN group respectively) show an apparent dependence on the electronic properties. The electronic properties in the redox conjugate, (5 a+) with Kc of 3.9×106 are further examined by UV-Vis-NIR and FTIR studies, showing optical responses in NIR region along with changes in “?Ru?C≡C?“ vibrational stretching frequency. The origin of the observed electronic transition has been assigned based on time-dependent DFT (TDDFT) calculations.
Roy, Sourav Saha,Chowdhury, Sabyasachi Roy,Mishra, Sabyashachi,Patra, Sanjib K.
supporting information
p. 3304 - 3313
(2020/09/09)

Synthesis and characterization of poly(tetramethylsilarylenesiloxane) derivatives with oligothiophene based moiety
Poly(tetramethylsilarylenesiloxane) derivatives (P1T-P4T, P4TC) that contained thiophene (1T), oligothiophenes such as dithiophene (2T), terthiophene (3T), quaterthiophene (4T), or 2,6-di(2-thienyl)-4,4-diphenylcyclopentadithiophene (4TC) as the main chain components were synthesized via polycondensation reaction of the corresponding disilanol monomers (M1T-M4T, M4TC). The obtained polymers other than P4T that contained quaterthiophene units exhibited the good solubility in common organic solvents, such as toluene, chloroform, tetrahydrofuran and so on. The glass transition temperature (Tg) and melting temperature (Tm) of the obtained polymers regarding P1T-P4T were increased with the extension of the thiophene rings of the monomeric unit as deduced from the results of the differential scanning calorimetry (DSC). On the other hand, the Tm was not observed for P4TC that was composed of 2,6-di(2-thienyl)-4,4-diphenylcyclopentadithiophene units. P2T that was composed of dithiophene units exhibited the highest temperature at 5% weight loss (Td5) of 467 °C in all present polymers. The bathochromic and hyperchromic effects in the absorption spectra as well as the improvement of fluorescence quantum yield were observed by the introduction of dimethylsilyl group onto the present oligothiophene derivatives. These effects became unremarkable accompanying the elongation of the thiophene rings of the monomeric units; however, 4TC exhibited a more significant change by the introduction of the dimethylsilyl group than the other oligothiophenes derivatives, indicating that the introduction of the cardo-structure was effective in the improvement of the optical properties. M4TC and P4TC exhibited the fluorescence wavelength around 500 nm and the highest fluorescence quantum yield of the present series of poly(tetramethylsilarylenesiloxane) derivatives, i.e., 0.40, plausibly because the free rotation between thiophene rings in oligothiophene inhibited by the cardo-structures and the bulky diphenyl groups at 4-position of cyclopentadithiophene moiety suppressed the nonradiative transition.
Nishizawa, Ibuki,Ajito, Hiroki,Gonmori, Yuzuki,Katoh, Ryuzi,Ichikawa, Tsukasa,Nemoto, Nobukatsu
p. 93 - 101
(2019/02/15)

Preparation method for synthesizing 2-azabicyclo[4.1.0]heptane-1-carboxylic acid hydrochloride
The invention discloses a preparation method for synthesizing 2-azabicyclo[4.1.0]heptane-1-carboxylic acid hydrochloride. The preparation method comprises the following steps: firstly obtaining a compound III through electrophilic substitution by taking N-substituted-1,2,3,6-tetrahydropyridine (compound II) as a raw material; carrying out cycloaddition reaction of the compound III and a sulfur ylide reagent to obtain a compound IV; finally carrying out deamination protecting group and ester hydrolysis to obtain the 2-azabicyclo[4.1.0]heptane-1-carboxylic acid hydrochloride (compound I).
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Paragraph 0021; 0022; 0023-0025

(2018/07/06)

Transition-metal-free decarboxylative bromination of aromatic carboxylic acids
Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.
Quibell, Jacob M.,Perry, Gregory J. P.,Cannas, Diego M.,Larrosa, Igor
p. 3860 - 3865
(2018/04/26)

Regioselective Halogenation of Arenes and Heterocycles in Hexafluoroisopropanol
Regioselective halogenation of arenes and heterocycles with N-halosuccinimides in fluorinated alcohols is disclosed. Under mild condition reactions, a wide diversity of halogenated arenes are obtained in good yields with high regioselectivity. Additionally, the versatility of the method is demonstrated by the development of one-pot sequential halogenation and halogenation-Suzuki cross-coupling reactions.
Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
p. 930 - 938
(2018/01/28)

Green halogenation reactions for (hetero)aromatic ring systems in alcohol, water, or no solvent
A new method of brominating aromatic and heteroaromatic ring systems is investigated. The combination of hydrobromic acid as the halogen source, hydrogen peroxide as the oxidant, and ethanol, water, or no solvent are evaluated as greener conditions than those that have been previously published. The new conditions give high yields and good regioselectivity for a variety of substrates when the ring is activated by electron-donating groups or heteroatoms. Phenols, anisole, thiophenes, and pyrrole give comparable or superior results when compared to a traditional bromination by N-bromosuccinimide in tetrahydrofuran. Other nitrogen-containing heterocycles do not react under the conditions because they are protonated and hence deactivated; similarly, substrates with electron-withdrawing groups are not brominated. The reaction is very tolerant of a variety of functional groups.
Kajorinne, Jessie K.,Steers, Jennifer C.M.,Merchant, Marnie E.,MacKinnon, Craig D.
p. 1087 - 1091
(2018/11/25)

TRIPHENYLAMINE COMPOUNDS, POLYMERS MADE THEREFROM AND ELECTROCHROMIC DEVICE COMPRISING THE SAME
The present invention relates to a triphenylamine compound, to a polymer thereof and to an electrochromic device comprising the same, and specifically, to a triphenylamine compound represented by the chemical formula (1), to a polymer thereof and to an electrochromic device comprising the same. In the chemical formula (1), R, R1, R2, R3, R4, and R5 are as defined in claim 1. The present invention also provides a triphenylamine-based polymer capable of forming a thin film having uniform surface and exhibiting excellent reversibility in the electrochromic characteristics.COPYRIGHT KIPO 2018
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Paragraph 0173; 0176-0179

(2018/05/03)

Synthesis and characterization of triphenylamine-based polymers and their application towards solid-state electrochromic cells
Four novel triphenylamine-based polymers, PJK1, PJK2, PJK3 and PJK4 were successfully synthesized and fully characterized by 1H NMR, UV-VIS spectroscopy, cyclic voltammetry (CV), GPC and spectroelectrochemistry. These polymers are easily soluble in many common organic solvents, which make them appropriate for film deposition via spray-coating. We fabricated electrochromic cells comprising ITO-coated glass/polymer/gel electrolyte/ITO-coated glass and patterned the color change by applying direct current with different voltages. We report herein color changes, from the neutral to oxidized form as follows: for PJK1, orange to dark green; for PJK2, light yellow to reddish brown; for PJK3, light blue to grey; and for PJK4, green to bluish green. The majority of the copolymers exhibited very good thermal stabilities, as evidenced by less than a 5% weight loss in temperatures exceeding 400 °C. To further characterize, we simulated the electrochemical and optical properties, which are good agreement with the experimental data.
Jeong, Jaemyeng,Kumar, Rangaraju Satish,Naveen, Mergu,Son, Young-A.
p. 78984 - 78993
(2016/09/09)

Acceptor-donor-acceptor small molecules containing benzo [1,2-b:4,5-b′]dithiophene and rhodanine units for solution processed organic solar cells
Two novel solution-processed acceptor-donor-acceptor (A-D-A) structured organic molecules with 5,8-disubstituted benzo[1,2-b:4,5-b′]dithiophene (BDT or BDTT) as central and donor units, 2-(1,1-dicyanomethylene)rhodanine (DCRD) as acceptor unit and terminal group, and trithiophene (T3) as π-bridges, D(T3-DCRD)-BDT and D(T3-DCRD)-BDTT, are designed and synthesized for the application as donor materials in organic solar cells (OSCs). Both compounds exhibit broad absorption covering the wavelength range 300-750 nm and the relatively lower HOMO energy levels from -5.39 to -5.46 eV. D(T3-DCRD)-BDTT demonstrates strong absorbance and higher hole mobility than that of D(T3-DCRD)-BDT. The power conversion efficiency (PCE) values of the OSCs based on the compounds/PC61BM (1:1, w/w) are 1.10% for D(T3-DCRD)-BDT and 1.94% for D(T3-DCRD)-BDTT, under the illumination of AM. 1.5G, 100 mW/cm-2. Furthermore, the high open-circuit voltage (Voc) values are 0.93 V for D(T3-DCRD)-BDT and 0.96 V for D(T3-DCRD)-BDTT, respectively. It indicates that incorporating DCRD as an acceptor unit into D-A-D-type small molecule has proven to be promising candidates for high efficiency solution processed OSCs.
Fan, Qunping,Li, Min,Yang, Pingao,Liu, Yu,Xiao, Manjun,Wang, Xiangdong,Tan, Hua,Wang, Yafei,Yang, Renqiang,Zhu, Weiguo
p. 13 - 19
(2015/03/05)

Green halogenation of aromatic heterocycles using ammonium halide and hydrogen peroxide in acetic acid solvent
The green generation of X+ (X = Br, I) using hydrogen peroxide in aqueous acetic acid allows access to aromatic heterocyclic halides in yields and purities comparable to syntheses employing N-bromosuccinimide. In activated and unsubstituted thiophene rings, regioselectivity is quantitative for positions α to the sulfur; pyrroles also give quantitative reactions, at least initially. Deactivated rings, including furans and thiazoles, as well as thiophenes with strongly electron-withdrawing groups showed little to no reactivity under the conditions investigated. The reaction shows remarkable functional group tolerance (to alcohol, nitro, alkyl, halo, and carbonyl groups), as shown through reaction with substituted phenols. In all bromination reactions, reaction yields and regiochemistry were very similar to reactions involving N-bromosuccinimide in tetrahydrofuran solvent.
D'Aleo, Danielle N.,Allard, Sheena R.,Foglia, Cassandra C.,Parent, Shawna L.M.,Rohr, David J.,Gottardo, Christine,MacKinnon, Craig D.
supporting information
p. 679 - 683
(2013/08/23)

METALLOENZYME INHIBITOR COMPOUNDS
The instant invention describes compounds having metalloenzyme modulating activity, and methods of treating diseases, disorders or symptoms thereof mediated by such metalloenzymes.
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Page/Page column 76

(2013/02/28)

Brominated methanes as photoresponsive molecular storage of elemental Br2
The photochemical generation of elemental Br2 from brominated methanes is reported. Br2 was generated by the vaporization of carbon oxides and HBr through oxidative photodecomposition of brominated methanes under a 20 W low-pressure mercury lamp, wherein the amount and situations of Br2 generation were photochemically controllable. Liquid CH 2Br2 can be used not only as an organic solvent but also for the photoresponsive molecular storage of Br2, which is of great technical benefit in a variety of organic syntheses and in materials science. By taking advantage of the in situ generation of Br2 from the organic solvent itself, many organobromine compounds were synthesized in high practical yields with or without the addition of a catalyst. Herein, Br2 that was generated by the photodecomposition of CH2Br2 retained its reactivity in solution to undergo essentially the same reactions as those that were carried out with solutions of Br2 dissolved in CH 2Br2 that were prepared without photoirradiation. Furthermore, HBr, which was generated during the course of the photodecomposition of CH2Br2, was also available for the substitution of the OH group for the Br group and for the preparation of the HBr salts of amines. Furthermore, the photochemical generation of Br2 from CH2Br2 was available for the area-selective photochemical bleaching of natural colored plants, such as red rose petals, wherein Br2 that was generated photochemically from CH 2Br2 was painted onto the petal to cause radical oxidations of the chromophoric anthocyanin molecules. The generation of Br 2 from brominated methanes occurred upon photoirradiation under O2. The solutions that contained elemental Br2 were useful for the synthesis of organobromine compounds and the macroscopic photochemical bleaching of colored plants. Copyright
Kawakami, Kazumitsu,Tsuda, Akihiko
p. 2240 - 2252
(2012/11/06)

Low band gap conjugated small molecules containing benzobisthiadiazole and thienothiadiazole central units: Synthesis and application for bulk heterojunction solar cells
Two novel conjugated low band gap small molecules (SMs), M1 and M2, containing benzobisthiadiazole and thienothiadiazole central units, respectively, were synthesized. Both SMs carried terminal cyanovinylene 4-nitrophenyl at both sides which were connected to the central unit with a thiophene ring. The long-wavelength absorption band was located at 591-643 nm and the optical band gap was 1.62-1.63 eV, which is lower than that of P3HT. These two SMs were investigated as electron donor materials along with PCBM or F as electron acceptors for fabrication of bulk heterojunction (BHJ) organic photovoltaic devices. F is a modified PCBM which has been previously synthesized and used as an electron acceptor for poly(3-hexylthiophene) (P3HT). The power conversion efficiency (PCE) for M1:PCBM, M1:F, M2:PCBM and M2:F was 1.05%, 2.02%, 1.23% and 2.72%, respectively. The higher PCE for the devices with M2 as the electron donor has been related to the improved hole mobility for M2. However, the improved PCE for the devices with F as the electron acceptor has been attributed to the more intense absorption of F in the visible region than that of PCBM and also to the higher open circuit voltage resulting from the higher LUMO level of F. We have also fabricated devices with M2:F cast film from mixed solvents. The PCE for the BHJ devices with the as cast and thermally annealed M2:F (mixed solvents) is 3.34% and 3.65%, respectively.
Mikroyannidis,Tsagkournos,Sharma,Vijay,Sharma
scheme or table
p. 4679 - 4688
(2011/10/13)

Influence of electron delocalization in heterocyclic core systems on the electrochemical communication in 2,5-Di-and 2,3,4,5-tetraferrocenyl thiophenes, furans, and pyrroles
A series of 2,5-di-and 2,3,4,5-tetraferrocenyl-substituted thiophenes, furans, and pyrroles were synthesized using the Negishi C,C cross-coupling protocol. The electronic and electrochemical properties of these compounds were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and in situ UV-vis/NIR spectroscopy. The molecular structures of 2,5-diferrocenyl furan and 2,3,4,5-tetraferrocenyl-1-methyl-1H-pyrrole in the solid state are discussed. The ferrocenyls could sequentially be oxidized giving two or four reversible responses for the appropriate di-or tetraferrocenyl-substituted heterocyclic molecules. The observed ΔE°′ values range between 186 and 450 mV. The NIR measurements confirm electronic communication as intervalence charge transfer (IVCT) absorptions were found in the corresponding mono-and in case of the tetraferrocenyl compounds also in the dicationic species. All compounds, except tetraferrocenyl thiophene (a class I system), were classified as class II systems according to Robin and Day. They show a linear relationship between ΔE°′ and the IVCT oscillator strength f which could be shown for the first time in organometallic chemistry. This was possible because the series of molecules exhibit analogous geometries and hence, similar electrostatic properties. This correlation was confirmed by electro-and spectro-electrochemical measurements. Within these studies a new approach for the estimation of the effective electron transfer distances r ab is discussed.
Hildebrandt, Alexander,Schaarschmidt, Dieter,Claus, Ron,Lang, Heinrich
body text
p. 10623 - 10632
(2011/12/13)

A novel method for the bromination of thiophenes
A novel, fast and convenient method for the bromination of thiophenes and oligothiophenes with N-bromosuccinimide (NBS) using ultrasonic irradiation is elaborated. The yield of bromothiophenes strongly depends on the initial thiophene structure and nature of the solvent.
Arsenyan, Pavel,Paegle, Edgars,Belyakov, Sergey
scheme or table
p. 205 - 208
(2010/03/24)

Soluble variable color carbazole-containing electrochromic polymers
Three new carbazole-containing polymers were synthesized through Suzuki cross-coupling between N-octylcarbazole-3,6-bis(ethyleneboronate) (NOctCz(BO2Et)2) and several arylene dibromides. 2,5-Dibromothiophene (DBT), 2,2′-dibromo-5,5′-bithiophene (DEBT), and 4,7-dibromo-2,1,3-benzothiadiazole (DBBTD) gave the three polymers PCzTh, PCzBi, and PCzBTD, respectively. Cyclic voltammetry showed two separate redox processes for each polymer, PCzTh (E1/2 = 0.33 V and E1/2 = 0.65 V vs Fc/ Fc+), PCzBi (E1/2 = 0.32 V and E 1/2 = 0.60 V vs Fc/Fc+), and PCzBTD (E1/2 = 0.56 V and E1/2 = 0.84 V vs Fc/Fc+). The two redox couples signify the presence of stable radical cation and dication oxidation states. In addition, the three materials were observed to display electrochromic properties. UV/vis/NIR absorbance spectroscopy revealed that each of the polymers displayed a unique absorbance maximum (345 nm for PCzTh, 375 nm for PCzBi, and 460 nm for PCzBTD) in their neutral states. Spectroelectrochemical analyses demonstrated that the π to π* transition was depleted upon application of increasingly positive potentials, giving rise to color changes. The different color states were quantified by colorimetry. PCzTh exhibits a yellow neutral state, a faint green radical cation state, and a pink dication state. PCzBi is yellow in its neutral state, light orange as a radical cation, and gray when fully oxidized. PCzBTD is orange when neutral, green-gray at intermediate potentials, and slate-gray as a dication.
Witker, David,Reynolds, John R.
p. 7636 - 7644
(2008/02/01)

Anisotropic organic compounds
STR1 The invention describes liquid crystalline compounds or formula (I), where A, D and G are independently selected from phenyl, thiophene, hydrogenated phenyl, chlorinated phenyl and fluorinated phenyl, B and E are independently selected from a single bond C= C. C C.C00, azoxy and diazo, k and m are independently selected from 1 and 0, such that m+n is 1 or 2, and R1 and R2 are independently selected from R, R0, alkynyl, thioalkyl, hydrogen, CN, NCS and SCN; provided that at least one of R1 and R2 is selected from CN, NCS and SCN and that at least one of A, D and G is phenyl; and excluding where at least one of R1 and R2 is independently selected as CN and one of A, D or G is not thiophene, and where m is 0, A, and D are phenyl, B is a single bond and only one of R1 or R2 is NCS. Also described are compounds suitable for inclusion in a device utilizing pretransitional characteristics of liquid crystalline materials in the isotropic phase, of general formula (II) where J and Y are independently selected from phenyl, thiophene, hydrogenated phenyl, chlorinated phenyl and fluorinated phenyl, X is selected from C= C. C C.COO azoxy and diazo, k is 1 or 0 and R3 and R4 are independently selected from R, RO, alkynyl, thioalkyl, hydrogen, CN, NCS and SCN; provided that at least one of R3 and R4 is selected from CN, NCS and SCN and that at least one of J and Y is phenyl.
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(2008/06/13)

Exclusive CIS-1,4-addition reaction in the bromination of 2,5-bis(trimethylsilyl)thiophene monooxide
2,5-Bis(trimethylsilyl)thiophene monooxide (1) underwent a 1,4-addition reaction with Br2 to give stereospecifically 2,5-bis(trimethylsilyl)-2,5-cis-dibromothiolene monooxide (2) in quantitative yield.
Zhang, Shao-Zhong,Sato, Soichi,Horn, Ernst,Furukawa, Naomichi
p. 227 - 234
(2007/10/03)

Naphthyl organic compounds
Liquid crystal compounds of formula (I) are described, where formula (I) is given as R1 --A--(Xm --(B)n --R2 where A is selected from nathyl, flourinated naphthyl, brominated naphthyl, B is selected from phenyl, methylated phenyl, brominated phenyl, fluorinated phenyl, thiophene, pyrimidine and pyridine, R1 and R2 are independently selected from alkyl, alkoxy, alkynyl, thioalkyl, Br, CN, SCN, NCS, perfluoroalkyl, perfluoroalkoxy and hydrogen, X is selected from C C, COO and C C, m is 0 or 1, n is 0 or 1 where m is 1 and n is 0 where m is 0; provided that where A is naphthyl, n is 1 and m is 0 then B is selected from methylated phenyl, brominated phenyl, thiophene, pyrimidine and pyridine; and further provided that where A is naphthyl, X is C C, m is 1 and n is 1, then B is selected from thiophene, pyrimidine and pyridine. Also described are liquid crystal compounds suitable for inclusion in devices utilizing pretransitional characteristics of liquid crystalline materials in the isotropic phase and described by formula (II): R3 --J--(Y)p --(Z)q --R 4, where J is selected from nathyl, fluorinated naphthyl, brominated naphthyl, Z is selected from phenyl, methylated phenyl, brominated phenyl, fluorinated phenyl, thiophene, pyrimidine and pyridine, R1 and R2 are independently selected from alkyl, alkoxy, alkynyl, thioalkyl, Br, CN, SCN, NCS, perfluoroalkyl, perfluoroalkoxy and hydrogen, Y is selected from C=C, COO and C=C, p is 0 or 1, q is 0 or 1 where p is 1 and q is 0 where p is 0.
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(2008/06/13)

PHOTOSYNTHESIS OF HETEROPOLYCYCLIC DIQUINOLONES TWOFOLD PHOTODEHYDROHALOGENATION REACTION OF BENZODITHIOPHENE- AND DITHIENOTHIOPHENEDICARBOXANILIDES
Heteropolycyclic diquinolones; benzodithieno-5,13-N,N'-dimethyldiquinoline-6,14-dione (9) and dithienothienyl-5,10-N,N-dimethyldiquinoline-6,9-dione (17) are prepared by twofold photochemical dehydrohalogenation reaction of corresponding benzodithiophene- and dithienothiophenedicarboxanilides; 3,7-dichloro-N,N'-dimethylbenzodithiophene-2,6-dicarboxanilide (8) and 3,5-dichloro-N,N'-dimethyldithienothiophene-2,6-dicarboxanilide (16).The products of onefold photochemical dehydrohalogenation reaction, anilidoquinolones; 9-chloro-10-N'-methylanilidobenzodithieno-5-N-methylquinolin-6-one (10) and 10-chloro-9-N'-methylanilidodithienothienyl-5-N-methylquinolin-6-one (18) were also isolated to prove the mechanism of the reaction.
Malesevic, Miro,Karminski-Zamola, Grace,Bajic, Miroslav,Boykin, David W.
p. 2691 - 2700
(2007/10/03)

SYNTHESIS OF SOME FURYL- AND THIENYLACRYLATES OR DIACRYLATES AND ACRYLIC ACIDS BY THE PALLADIUM CATALYSED VINYLATION OF SUBSTITUTED BROMOFURANS AND BROMOTHIOPHENES
Furyl- and thienylacrylates (8-14) and acrylic acids (8a,10a-14a) are prepared in moderate yields by palladium catalysed coupling of substituted bromofurans and bromothiophenes with ethyl acrylate.
Karminski-Zamola, Grace,Dogan, Jasna,Bajic, Miroslav,Blazevic, Jelena,Malesevic, Miroslav
p. 759 - 768
(2007/10/02)

Biphasic Electrophilic Halogenation of Activated Aromatics and Heteroaromatics with N-Halosuccinimides Catalyzed by Perchloric Acid
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
p. 3072 - 3075
(2007/10/02)

Extensively Conjugated Tetrathiafulvalene (TTF) ?-Electron Donors with Oligothiophenes Spacer Groups
New extended p-donors combining the tetrathiafulvalene (TTF) system with the conjugated backbone of substituted terthienyls are described.
Roncali, Jean,Giffard, Michel,Frere, Pierre,Jubault, Michel,Gorgues, Alain
p. 689 - 691
(2007/10/02)

1,8-Diazabicycloundec-7-ene Hydrobromide Perbromide: A New Mild Stable Brominating Agent for Aromatic Compounds
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Muathen, Hussni A.
p. 2740 - 2741
(2007/10/02)

Halogenation Using Quaternary Ammonium Polyhalides. XXXI. Halogenation of Thiophene Derivatives with Benzyltrimethylammonium Polyhalides
The reactions of thiophene derivatives with benzyltrimethylammonium tetrachloroiodate, benzyltrimethylammonium tribromide, and benzyltrimethylammonium dichloroiodate in acetic acid or in acetic acid-zinc chloride under mild conditions gave chloro-, bromo-, and iodo-substituted thiophene derivatives, respectively, in satifactory yields.
Okamoto, Tsuyoshi,Kakinami, Takaaki,Fujimoto, Hiroshi,Kajigaeshi, Shoji
p. 2566 - 2568
(2007/10/02)

Charge Density - Activation Energy Correlations in Bromination of Thiophenes by N-Bromosuccinimide in Solution
The activation energies for N-bromosuccinimide bromination of several thiophene derivatives in 80percent (v/v) aqueous acetic acid have been determined and discussed in the light of electron densities at the reaction site.The effect of substituents at different positions of thiophene ring has been investigated quantitatively by the actual calculation of total (? + ?) charge densities at various positions of the substituted thiophenes.
Rajaraman, Lalitha,Nanjan, M. J.
p. 538 - 539
(2007/10/02)

Convenient High-Yield Procedures for 2-Bromothiophene and 2,5-Dibromothiophene
2-Bromothiophene is obtained in high yields by adding a solution of bromine in 48percent hydrobromic acid or a 35percent aqueous solution of hydrogen peroxide to a mixture of thiophene, diethyl ether, and 48percent hydrobromic acid. 2,5-Dibromothiophene is obtained in >90percent yields from thiophene and bromine in hydrobromic acid.
Keegstra, M. A.,Brandsma, L.
p. 890 - 891
(2007/10/02)

Photochemical Synthesis of Phenyl-2-thienyl Derivatives
The irradiation (in benzene solution) of 5-bromo- and 5-iodo-thiophene-2-carbaldehyde or the corresponding methyl ketones furnishes the corresponding 5-phenyl derivatives.The same reactivity for other halogenothiophenes is reported: 3,5-dibromothiophene-2-carbaldehyde furnishes the 3-bromo-5-phenyl-2-thienyl derivative while the corresponding di-iodo compound yields 3,5-diphenylthiophene-2-carbaldehyde.In contrast, 5-acetyl-2,3-di-iodothiophene furnishes only the photosubstitution pruduct at C-5.Generally the iodine-containing compounds are more reactive and more stable under the reaction conditions than ones bearing bromine, in agreement with previous reports on the corresponding furan photochemistry.
Antonioletti, Roberto,Auria, Maurizio D',Onofrio, Franco D',Piancatelli, Giovanni,Scettri, Arrigo
p. 1755 - 1758
(2007/10/02)

Novel Bromination Reagents. Electrophilic Aromatic Bromination by Hexabromocyclopentadiene
Hexabromocyclopentadiene efficiently and regioselectively brominates activated aromatic compounds, in a process which is interpreted as involving ready formation of the pentabromocyclopentadienide anion by bromonium ion release.
Fuchs, Benzion,Belsky, Yigal,Tartakovsky, Evgeny,Zizuashvili, Jakob,Weinman, Sarah
p. 778 - 779
(2007/10/02)

Charge Density - Activation Energy Correlations in Electrophilic Bromination of Thiophenes
Charge density calculations are made on eleven thiophenes by Hueckel LCAO MO and Del Re methods and correlated with experimental activation energies(Ea) obtained for the molecular bromination of these compounds.The need for the inclusion of ?-charges in any correlation of charge density with kinetic data is stressed. - Keywords: Charge density/ Activation energy / Bromination of thiophenes
Nanjan, M. J.,Kannappan, V.,Ganesan, R.
p. 13 - 22
(2007/10/02)

Kinetics of Bromination of Certain Substituted Thiophenes in Solution
The general features of the kinetics of bromination of thiophene and substituted thiophenes have been investigated in dry and 15percent aq. acetic acid (v/v) and the Arrhenius activation energy (Ea) accurately determined for ten thiophene derivatives and interpreted.The mechanism proposed is supported with the detection of a ?-complex between bromine and 2-bromothiophene.
Kannappan, V.,Nanjan, M. J.,Ganesan, R.
p. 1183 - 1187
(2007/10/02)