cas 808-57-1, 2,3,6,7,10,11-Hexamethoxytriphenylene

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Synthesis, structure and properties of C3-symmetric heterosuperbenzene with three BN units
The parent skeleton of BN heterocoronene with three BN units and C3 symmetry was synthesized as a model compound of BN-doped graphene. Further investigation of this graphene-type molecule revealed the important role of BN doping in opening the
Wang, Xiao-Ye,Zhuang, Fang-Dong,Wang, Xin-Chang,Cao, Xiao-Yu,Wang, Jie-Yu,Pei, Jian
p. 4368 - 4371
(2015)
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Novel Large π-Conjugated Coronene-Based Molecules: Diaryl-Substituted 1,2,7,8,13,14-Hexamethoxytribenzo[a,g,m]coronenes
Abstract: A series of novel coronene-based fluorescent materials have been synthesized through well-defined protocol from 1,2-dimethoxybenzene, with the key steps including Suzuki–Miyaura coupling and oxidative cyclodehydrogenation with ferric chloride. F
An, Shujie,Liu, Qiancai,Ma, Li,Tang, Guofeng,Zhong, Yaling
p. 1779 - 1783
(2020)
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Synthesis and Complex Crystal Structure of C60 with Symmetrical Donor of 2,3,6,7,10,11-Hexamethoxytriphenylene (HMT)
We have successfully synthesized the complex of C60 fullerene with a three-fold symmetrical donor of 2,3,6,7,10,11-hexamethoxytriphenylene (HMT).All spectroscopic data, and analyses support the chemical composition of this complex as C60(HMT)2.Individually, each C60 fullerene sphere was found to be surrounded by four HMT molecules in distinctive tetrahedral arrangement.The closest distance from one C60 centroid to the next C60 centroid in the adjacent chain is 13.099 Angstroem.
Chiang, Long Y.,Swirczewski, John W.,Liang, Ken,Millar, J.
p. 981 - 984
(1994)
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Mesomorphic triphenylene polyanion-surfactant complexes
Triphenylene derivatives have been reported as one of the prominent members of discotic liquid crystalline systems. This report gives an account of the mesomorphic behavior of complexes involving triphenylene and double tail surfactants synthesized through the ionic self-assembly route. The lamellar structure of these complexes has been determined using X-ray diffraction, differential scanning calorimetry and polarizing optical microscopy. The amphotropic nature of these complexes has also been studied.
K, Swamynathan,Sasidharan, Sreeja,V.A, Raghunathan,Kumar, Sandeep
(2020/12/02)

Synthesis of Boroxine and Dioxaborole Covalent Organic Frameworks via Transesterification and Metathesis of Pinacol Boronates
Boroxine and dioxaborole are the first and some of the most studied synthons of covalent organic frameworks (COFs). Despite their wide application in the design of functional COFs over the last 15 years, their synthesis still relies on the original Yaghi's condensation of boronic acids (with itself or with polyfunctional catechols), some of which are difficult to prepare, poorly soluble, or unstable in the presence of water. Here, we propose a new synthetic approach to boroxine COFs (on the basis of the transesterification of pinacol aryl boronates (aryl-Bpins) with methyl boronic acid (MBA) and dioxaborole COFs (through the metathesis of pinacol boronates with MBA-protected catechols). The aryl-Bpin and MBA-protected catechols are easy to purify, highly soluble, and bench-stable. Furthermore, the kinetic analysis of the two model reactions reveals high reversibility (Keq ～1) and facile control over the equilibrium. Unlike the conventional condensation, which forms water as a byproduct, the byproduct of the metathesis (MBA pinacolate) allows for easy kinetic measurements of the COF formation by conventional 1H NMR. We show the generality of this approach by the synthesis of seven known boroxine/dioxaborole COFs whose crystallinity is better or equal to those reported by conventional condensation. We also apply metathesis polymerization to obtain two new COFs, Py4THB and B2HHTP, whose synthesis was previously precluded by the insolubility and hydrolytic instability, respectively, of the boronic acid precursors.
Hamzehpoor, Ehsan,Jonderian, Antranik,McCalla, Eric,Perepichka, Dmitrii F.
supporting information
p. 13274 - 13280
(2021/09/07)

Highly ordered smectic structures of disc-rod luminescent liquid crystals: The role of the tolane group
Two novel calamitic tolane luminogen-modified triphenylene-based discotic luminescent liquid-crystals (LLC) were rationally designed and synthesized to investigate the self-assembly competition between triphenylene discogens and tolane calamitic mesogens.
Liu, Yurong,Li, Wei,Zhou, Xuan,Wong, Wai-Yeung,Yu, Zhen-Qiang
supporting information
p. 3555 - 3561
(2021/03/26)

A 6π Azaelectrocyclization Strategy towards the 1,5,9-Triazacoronenes
We present the instance of two aromatic double bonds and an imine double bond involved thermal 6π-azaelectrocyclization and, on this basis, a one-step synthesis of triazacoronenes (TACs) from triphenylene-1,5,9-triamines and aldehydes under nonacidic cond
Li, Jing,Shen, Guo-Dong,Sun, Hua-Ming,Sun, Yi-Xun,Wang, Xiao-Gang,Wei, Jun-Fa,Yang, Ming-Yu,Yang, Tian,Yang, Yi-Hui
supporting information
p. 1651 - 1656
(2020/01/25)

Carbocatalytic Oxidative Dehydrogenative Couplings of (Hetero)Aryls by Oxidized Multi-Walled Carbon Nanotubes in Liquid Phase
HNO3-oxidized carbon nanotubes catalyze oxidative dehydrogenative (ODH) carbon–carbon bond formation between electron-rich (hetero)aryls with O2 as a terminal oxidant. The recyclable carbocatalytic method provides a convenient and an operationally easy synthetic protocol for accessing various benzofused homodimers, biaryls, triphenylenes, and related benzofused heteroaryls that are highly useful frameworks for material chemistry applications. Carbonyls/quinones are the catalytically active site of the carbocatalyst as indicated by model compounds and titration experiments. Further investigations of the reaction mechanism with a combination of experimental and DFT methods support the competing nature of acid-catalyzed and radical cationic ODHs, and indicate that both mechanisms operate with the current material.
Wirtanen, Tom,Aikonen, Santeri,Muuronen, Mikko,Melchionna, Michele,Kemell, Marianna,Davodi, Fatemeh,Kallio, Tanja,Hu, Tao,Helaja, Juho
supporting information
p. 12288 - 12293
(2019/09/06)

Self-Organized Frameworks on Textiles (SOFT): Conductive Fabrics for Simultaneous Sensing, Capture, and Filtration of Gases
Wearable electronics have the potential to advance personalized health care, alleviate disability, enhance communication, and improve homeland security. Development of multifunctional electronic textiles (e-textiles) with the capacity to interact with the local environment is a promising strategy for achieving electronic transduction of physical and chemical information. This paper describes a simple and rapid approach for fabricating multifunctional e-textiles by integrating conductive two-dimensional (2D) metal-organic frameworks (MOFs) into fabrics through direct solution-phase self-assembly from simple molecular building blocks. These e-textiles display reliable conductivity, enhanced porosity, flexibility, and stability to washing. The functional utility of these integrated systems is demonstrated in the context of chemiresistive gas sensing, uptake, and filtration. The self-organized frameworks on textiles (SOFT)-devices detect and differentiate important gaseous analytes (NO, H2S, and H2O) at ppm levels and maintain their chemiresistive function in the presence of humidity (5000 ppm, 18% RH). With sub-ppm theoretical limits of detection (LOD for NO = 0.16 ppm and for H2S = 0.23 ppm), these constitute the best textile-supported H2S and NO detectors reported and the best MOF-based chemiresistive sensors for these analytes. In addition to sensing, these devices are capable of capturing and filtering analytes.
Smith, Merry K.,Mirica, Katherine A.
supporting information
p. 16759 - 16767
(2017/11/28)

METHOD FOR OXIDATIVE COUPLING OF AROMA COMPOUND, OXIDIZING AGENT USED IN THIS METHOD, AND OXIDIZED FLAKED GRAPHITE USED AS OXIDIZING AGENT
PROBLEM TO BE SOLVED: To provide a method for oxidative coupling of aroma compounds using an oxidizing agent used at the time of oxidative coupling of aroma compounds which facilitates separation of residues of the oxidizing agent as a by-product produced together with a target coupling product and can reduce by-product disposal cost, and an oxidizing agent used in the method and oxidized flaked graphite used as an oxidizing agent. SOLUTION: In a method for oxidatively coupling aromatic compounds by adding an oxidizing agent to a solution in which the aromatic compounds have been dissolved to cause an oxidative coupling reaction, oxidized flaked graphite flaked by oxidizing graphite is used as the oxidizing agent. More particularly, the oxidized flaked graphite is produced by adding graphite to a mixed solution of sodium nitrate, sulfuric acid, and potassium permanganate. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2017,JPOandINPIT
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(2017/03/25)

Bottom-up synthesis of fully sp2 hybridized three-dimensional microporous graphitic frameworks as metal-free catalysts
We report on the bottom-up synthesis of a fully sp2-hybridized nitrogenated three-dimensional microporous graphitic framework (3D-MGF) starting from a highly preorganized, saddle-shaped tetraphenylene derivative under ionothermal reaction condi
Talapaneni, Siddulu Naidu,Kim, Jaehoon,Je, Sang Hyun,Buyukcakir, Onur,Oh, Jihun,Coskun, Ali
supporting information
p. 12080 - 12085
(2017/07/10)

Synthesis and liquid crystalline studies of disc-shaped molecule on azo-bridged benzothiazole-phenyl ethers
A new series of triphenylene core attached by six peripheral arms containing benzothiazole-azo with terminal ethoxy unit have successfully been synthesized and their liquid crystalline properties were characterized. The members in this series differ by the length of the methylene unit of [sbnd](CH2)n[sbnd], where n, varied following ascending order from 5 to 10. The molecular structure was characterized by elemental (C, H and N) analysis and spectroscopic methods including Fourier Transform Infrared (FT-IR) and Proton Nuclear Magnetic Resonance (1H NMR). The texture and the phase transition temperatures were investigated by using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The disc-shape molecule with shorter spacer (n?=?5) showed monotropic nematic phase. The higher homologues with n?=?8–10 exhibited enantiotropic nematic phase and monotropic smectic C phase. The XRD diffraction studies further confirm the presence of smectic C without any discotic columnar phase.
Yeap, Guan-Yeow,Abdul Rahim, Mursyida,Lin, Chien-Min,Lin, Hong-Cheu,Maeta, Nobuyuki,Ito, Masato M.
p. 734 - 740
(2016/09/09)

Aerobic Oxidative Intramolecular Aromatic Coupling via Heterogeneous Metal Catalysts
An aerobic, heterogeneously catalyzed oxidative intramolecular coupling reaction of aromatic compounds is reported here. Using commercially available, recyclable heterogeneous metal catalysts, the coupling reactions of o-terphenyls and 1,ω-biarylalkanes proceeded quickly under mild conditions, i.e., at room temperature under oxygen as a co-oxidant almost all within 1 h, to provide the corresponding coupled products like triphenylenes and phenanthrenes in good to excellent yields. This reaction is an easily handled, practical, and atom-economical coupling method, which is of great importance in modern organic syntheses. (Figure presented.).
Fujimoto, Shigenobu,Matsumoto, Kenji,Shindo, Mitsuru
supporting information
p. 3057 - 3061
(2016/10/09)

Method of manufacturing tripenylene compd.
PROBLEM TO BE SOLVED: To provide a method for producing a 2,3,6,7,10,11-hexasubstituted triphenylene compound in a high yield which enables mass production at a low cost and on an industrial scale and reduces the load to the environment as much as possible. SOLUTION: The method for producing a 2,3,6,7,10,11-hexasubstituted triphenylene compound by the trimerization reaction of a 1,2-disubstituted benzene compound in the presence of a compound including a divalent or trivalent iron ion comprises using at least one reaction solvent selected from the group consisting of carboxylic acid esters, lactones, carbonic acid esters, and sulfurous esters in the reaction. COPYRIGHT: (C)2013,JPOandINPIT
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(2016/10/09)

Oxidative cyclotrimerization of unsaturated compounds with DDQ and triflic acid: An efficient synthetic route to triply-fused benzene rings
Intermolecular oxidative cyclotrimerization reactions of alkenes and aromatic compounds with DDQ and trifluoromethanesulfonic acid are described. Scholl-type oxidation reactions involving alkenes have not previously been demonstrated. Moreover, the DDQ/acid system has never been used for intermolecular oxidative cyclization reactions. This convenient, metal-free reagent system (DDQ/TfOH) is advantageous with respect to metal-based Scholl-type oxidants because it eliminates the possibility of halogenation of aromatic compounds as a competing side reaction.
Cho, Hee Yeon,Scott, Lawrence T.
supporting information
p. 3458 - 3462
(2015/01/30)

UV-visible absorption study of the selfassociation of non-ionic chromonic triphenylenes TP6EOnM (n = 2, 3, 4) in dilute aqueous solutions: Impact of chain length on aggregation
A series of triphenylenes with oligoethoxy chains of various length, TP6EOnM with n = 2, 3, 4, has been synthesised and purified by HPLC. The self-association of these disc-shaped molecules in dilute aqueous solutions (~10-7 to ~4 × 10-4 M) has been studied by UV-visible absorption spectroscopy. The free energy of association decreases as the length of the chains increases. As a result, for a given concentration, the average size of aggregate diminishes as the chain length increases. While the absorption properties of the monomer are identical for the three molecules, the extinction coefficients of solutions of the three triphenylenes at a given concentration are significantly different and are directly linked to the average size of the aggregates. The change of epsilon values upon aggregation could explain the trend generally observed with dyes for solar cells substituted with chains of increasing length showing increasing extinction coefficient values.
Herbaut, Antoine,Baranoff, Etienne
p. 520 - 523
(2015/10/28)

Use of 2-bromophenylboronic esters as benzyne precursors in the Pd-catalyzed synthesis of triphenylenes
ortho-Substituted aryl boronates are introduced as aryne precursors for transition-metal-catalyzed transformations. On treatment with tBuOK and Pd(0), metal-bound aryne intermediates are formed that undergo effective trimerization to form useful triphenylene compounds. For meta-substituted arynes, the 3:1 product ratio in favor of non-C3 symmetric material is indicative of a benzyne mechanism.
Garcia-Lopez, Jose-Antonio,Greaney, Michael F.
p. 2338 - 2341
(2014/05/20)

1,5,9-triazacoronenes: A family of polycyclic heteroarenes synthesized by a threefold pictet-spengler reaction
We are family: Triazacoronene derivatives have been synthesized in four steps from veratrole by using a threefold Pictet-Spengler reaction as the key step (see picture). They have good photophysical and electronical properties, thermal stability, and solu
Wei, Junfa,Han, Bo,Guo, Qiang,Shi, Xianying,Wang, Wenliang,Wei, Ni
scheme or table
p. 8209 - 8213
(2011/02/22)

PROCESS FOR PRODUCING TRIPHENYLENE COMPOUND AND CRYSTAL OBTAINED BY THE PROCESS
An object of the present invention is to provide a process for producing high-purity hydroxytriphenylenes in which not only inexpensive raw materials can be used but also no complicated steps of deprotection such as dealkylation, and reduction and the like are necessary, and which is thereby advantageous in industrial production. Also there is provided a novel crystal of 2,3,6,7,10,11-hexahydroxytriphenylene monohydrate, which has satisfactory thermal stability. The process for producing a compound represented by the general formula (2) is characterized by reacting a compound represented by the general formula (1) in the presence of a metal oxide comprising a metal selected from trivalent iron, pentavalent vanadium and hexavalent molybdenum and of a nonvolatile strong acid: wherein, Rs are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms.
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(2010/05/13)

Self-assembly of dendronized triphenylenes into helical pyramidal columns and chiral spheres
The synthesis and structural and retrostructural analyses of a library containing 10 triphenylenes functionalized with self-assembling benzyl ether and phenyl propyl ether dendrons are reported. These dendronized triphenylenes adopt a crown rather than discotic conformation. Their crown conformation mediates the self-assembly of the discotic triphenylene unit in helical pyramidal columns and in chiral spheres. The chiral spheresare generated from short segments of helical pyramidal columns that are spherically distorted. Therefore, the chirality of the sphere is determ ined by a short helical pyramidal column that represents the inner part of the supramolecular sphere. Both the helical pyramidal columns and thechiral spheres represent supramolecular architectures that were self-as sembled for the first time from discotic molecules. The helical pyramidal columns self-organize in various hexagonal and rectangular lattices, while the chiral spheres self-organize into cubic and tetragonal periodicarrays and into a quasiperiodic 12-fold liquid quasicrystal. The helica l sense of the helical pyramidal columns and of helical spheres is selected by a stereocenter that can be incorporated either in the alkyl groups of the dendron or in the triphenylene part of the dendritic crown via donor-acceptor interactions. The self-assembly process of the dendronized triphenylene donor can be programmed by a new supramolecular "polymer effect" generated by donor-acceptor interactions.
Percec, Virgil,Imam, Mohammad R.,Peterca, Mihai,Wilson, Daniela A.,Graf, Robert,et al.
supporting information; experimental part
p. 7662 - 7677
(2009/10/17)

Synthesis and specific features of mesomorphic behavior of new polysubstituted triphenylenes
Previously unknown 2,3,6,7,10,11-hexakis(dodecyloxy)triphenylene and -(tetradecyloxy)triphenylene were synthesized. The structures of the synthesized compounds were proved by elemental analysis and spectral methods. Polymesomorphism was found for the first time and studied for substances of the hexaalkoxytriphenylene homologic series, as well as liotropic mesomorphism in a series of organic solvents.
Zemtsova,Zheleznov
p. 1743 - 1748
(2007/10/03)

Columnar mesophase from a new hybrid siloxane-triphenylene
The design, the synthesis and the mesomorphic properties of a new disc-like mesogen based on a hexasubstituted triphenylene core terminated with pentamethyldisiloxane pendant groups are reported. The siloxane fragments were grafted to the six terminal olefinic branches of a triphenylene precursor by a Pt-catalysed hydrosilylation reaction. Both the hexaolefinic and the hexasiloxane derivatives are mesomorphic, showing a rectangular columnar (ColR - p2gg) mesophase between 55 and 88°C for the former, and a broad hexagonal (ColH - p6mm) mesophase between ambient temperature and 125°C for the latter. The liquid crystalline behaviour was investigated by means of differential scanning calorimetry, polarised-light optical microscopy, and X-ray diffractometry. The mesophase temperature range and stability were considerably extended for the hybrid compound with respect to the siloxane-free compound. This behaviour is explained on the basis of enhanced microsegregation between the chemically distinct constituent components of the molecule.
Zniber, Rachid,Achour, Redouane,Cherkaoui, Mohammed Zoubair,Donnio, Bertrand,Gehringer, Lionel,Guillon, Daniel
p. 2208 - 2213
(2007/10/03)

Synthesis and investigation of polysubstituted triphenylenes with a predictable type of mesomorphism
This paper reports on synthesis and investigation of columnar mesophases of the new members of the homologous series of nitro and amino derivatives of hexaalkoxytriphenylenes, whose mesomorphism was predicted earlier. The forecast is in good agreement with the experimental data. The effect of the introduction of the donor and acceptor groups into the central fragment of triphenylene on the phase transition temperature, texture, and range of existence of columnar mesophases is examined. The predicting ability of the molecular parameters suggested previously for the series under analysis is discussed. It is found that introduction of a nitro group, which is a strong electron acceptor, into the central fragment of triphenylene lowers the melting temperature of the compound versus its analog and does not promote columnar mesomorphism in the lower nonmesomorphous homologs. At the same time, this slightly expands the range of existence of the mesophase in higher homologs.
Zemtsova,Syromyatnikova,Kotovich,Akopova
p. 38 - 42
(2007/10/03)

Synthesis of hexa-alkyloxytriphenylenes using FeCl3 supported on alumina
Several symmetrical and unsymmetrical hexa-alkyloxytriphenylenes have been synthesised in good yield from diakyloxy benzenes and terphenyl derivatives using FeCl3 supported on alumina.
Cooke, Graeme,Sage, Valerie,Richomme, Tanguy
p. 1767 - 1771
(2007/10/03)

Oxidative trimerization of o-dialkoxybenzenes to hexaalkoxytriphenylenes: Molybdenum(v) chloride as a novel reagent
Symmetrically substituted hexaalkoxytriphenylenes are obtained from o-dialkoxybenzenes by oxidative trimerization with MoCl5 in high yields; oxidative coupling of a 3,3′,4,4′-tetraalkoxybiphenyl and 1,2-dialkoxybenzenes yields unsymmetrically substituted derivatives of triphenylene and a direct coupling of a 3,3′,4,4′-tetraalkoxybiphenyl with alkoxyphenol produces the monofunctionalized triphenylenes.
Kumar, Sandeep,Manickam
p. 1615 - 1616
(2007/10/03)

Purification of 2,3,6,7,10,11-Hexamethoxytriphenylene and preparation of hexakiscarbonylmethyl and hexakiscyanomethyl derivatives of 2,3,6,7,10,11-Hexahydroxytriphenylene
2,3,6,7,10,11-Hexamethoxytriphenylene (1) was subjected to an improved purification procedure and demethylated to give 2,3,6,7,10,11-hexahydroxytriphenylene (2) as the relatively stable trihydrate. Compound 2 was alkylated with reactive halogen reagents g
Krebs,Schiodt,Batsberg,Bechgaard
p. 1285 - 1290
(2007/10/03)

Triphenylene Columnar Liquid Crystals: Excited States and Energy Transfer
The present paper deals with the photophysical properties of columnar liquid crystals formed by hexakis(alkyloxy)triphenylenes.Absorption and fluorecence spectra of solutions are analyzed on the basis of quantum chemical calculations performed by the CS-INDO-CI (conformations spectra-intermediate neglect of differential overlap-configuration interaction) method: the absorption maximum is due to the S0->S4 transition while fluorescence originates from the weak S0->S1 transition.In columnar aggregates, the former transition corresponds to delocalized excited states while the latter corresponds to localised ones; calculation of intermolecular interactions shows that, at the temperature domain of the mesophases, all the molecules have the same excitation energy and, therefore, no spectral diffusion of the fluorescence is expected, in agreement with the time-resolved emission spectra.Excitation transfer is investigated by studying the fluorescence decays of mesophases doped with energy traps.Their analysis is made by means of Monte Carlo simulations considering both intracolumnar and intercolumnar jumps and using four different models for the distance dependence of the hopping probability.The best description is obtained with a model based on the extended dipole approximation and taking into account molecular orientation.
Markovitsi, Dimitra,Germain, Arnaud,Millie, Philippe,Lecuyer, Pierre,Gallos, Lazaros K.,at al.
p. 1005 - 1017
(2007/10/02)

A Quick-and-Easy Route to Unsymmetrically Substituted Derivatives of Triphenylene: Preparation of Polymeric Discotic Liquid Crystals
Unsymmetrically substituted triphenylenes can be obtained by the iron(III) chloride mediated oxidative coupling of a 3,3',4,4'-tetraalkoxybiphenyl with a 1,2-dialkoxybenzene thus opening up a practicable route to polymeric discotic liquid crystals.
Boden, Neville,Bushby, Richard J.,Cammidge, Andrew N.
p. 465 - 466
(2007/10/02)

A high yield easy method for the preparation of alkoxy-substituted triphenylenes
2,3,6,7,10,11-Hexamethoxytriphenylene is prepared by oxidative trimerization of 1,2-dimethoxybenzene (veratrol) with iron(III) chloride/sulfuric acid in nearly quantitative yield. The obtained crude product is almost pure. Other alkoxy-substituted triphenylenes are also synthesized by this method.
Naarmann,Hanack,Mattmer
p. 477 - 478
(2007/10/02)

A VERSATILE ANODIC SOURCE OF TRIPHENYLENES POSSESSING AT LEAST ONE IONOPHORIC SITE
mixed anodic trimerization of aromatic orthodiesters and benzocrown ethers may lead to the formation of new triphenylenes possessing one (or two) complexing site(s).
Chapuzet, Jean-Marc,Simonet-Gueguen, Noelle,Taillepied, Isabelle,Simonet, Jacques
p. 7405 - 7408
(2007/10/02)

THE ANODIC TRIMERIZATION OF AROMATIC ORTHODIETHERS: NEW DEVELOPMENTS
While the anodic trimerization of veratrole (leading to hexamethoxytriphenylene) is now a very well known reaction, developments concerning either mixed electrolysis (mixture of two orthodiethers) and/or oxidation of dissymmetrical substrates have not bee
Chapuzet, Jean-Marc,Simonet, Jacques
p. 791 - 798
(2007/10/02)

CHARGE TRANSFER SALTS OF HIGHLY ORIENTED FIBERS OF DISCOTIC LIQUID CRYSTAL HET-n
The charge transfer salt of highly oriented fibers of discotic liquid crystals of 2,3,6,7,10,11-hexa-alkoxytriphenylene (HET-n) and 2,3,6,7,10,11-hexa-alkanoyloxytriphenylene (HAT-n) can be made by a strand technique followed by a doping process.As a result, the bromide doped HET-5 fiber shows a conductivity of three orders of magnitude higher than that of the bromine doped HET-5 powder.
Chiang, Long Y.,Stokes, James P.,Safinya, Cyrus R.,Bloch, Aaron N.
p. 279 - 288
(2007/10/02)

Unsymmetrical Anodic Coupling of Veratrole with Various Anisole Derivatives. Products and Mechanisms
The coelectrolysis of veratrole (1) with anisole (2a), phenetole (2b), 3-methylanisole (2c), 2-methylanisole (3), 2,5-dimethylanisole (4), and 2,6-dimethylanisole (6) have been investigated in trifluoroacetic acid-dichloromethane solvent.With 2a-c good yields of "tetrameric" 5-aryl substituted triphenylene derivatives (10a, 10b or 11) were obtained, probably by initial coupling of the veratrol cation radical (1.+) with the anisole derivative or its cation radical to an unsymmetrical dimer (8 or 11) followed by dimerisation and intramolecular cyclisation to the product.With 3,4 or 5 only "trimeric" products from coupling of two veratrole units with one of the anisole units (15 or 26) or from coupling of one veratrole unit with two of the anisole units (17,22,25 or 27) were observed.
Ronlan, Alvin,Aalstad, Bjoerg,Parker, Vernon D.
p. 317 - 326
(2007/10/02)

Thallium in Organic Synthesis. 58. Regiospecific Intermolecular Oxidative Dehydrodimerization of Aromatic Compounds to Biaryls Using Thallium (III) Trifluoroacetate
Treatment of a variety of aromatic substrates with thallium(III) trifluoroacetate (TTFA) in trifluoroacetic acid (TFA), or in carbon tetrachloride or acetonitrile containing boron trifluoride etherate, results in smooth, rapid, and direct regiospecific oxidative dehydrodimerization to give symmetrical biaryls in good to excellent yield.The method is particularly useful when applied to substrates in which the ring substituents are either electron donating or mildly electron withdrawing.Aromatic substrates which contain powerful electron-withdrawing groups (CN, COOR, NO2) fail to react.The reaction is postulated to proceed via (a) reaction of TTFA with the aromatic substrate and generation of the radical cation Ar+; (b) reaction of this electrophile with the aromatic substrate; (c) oxidative aromatization of the intermediate thus produced by TTFA.Biaryls can be obtained similarly by oxidation of the same substrates with either mercury(II) trifluoroacetate in TFA containing boron trifluoride, lead(IV) acetate in acetonitrile containing boron trifluoride, iron(III) chloride in methylene chloride, or cobalt(III) fluoride in TFA.Yields in the Hg(II) and Fe(III) reactions are generally inferior to those obtained with TTFA, but those obtained in the Pb(IV) and Co(III) oxidations are in many instances comparable to, or even better than, the TTFA results.The oxidations with Hg(II), Pb(IV), Fe(III), and CO(III) are also postulated to proceed via a radical cation mechanism.
McKillop, Alexander,Turrell, Andrew G.,Young, Derek W.,Taylor, Edward C.
p. 6504 - 6512
(2007/10/02)