Studies on Pd/NiFe₂O₄ catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

• Sanjay R. Borhade and
• Suresh B. Waghmode

Beilstein J. Org. Chem. 2011, 7, 310–319, doi:10.3762/bjoc.7.41

• products, pharmaceutical intermediates, pesticides, advanced materials and liquid crystals [8][9][10]. These applications, in turn, have led to the production of biaryls and polyaryls on the industrial scale [11]. The Suzuki reaction is usually performed with homogeneous palladium catalysts in the presence

• , antithrombotic, anticoagulant and cytotoxic activities [44][45][46][47]. Polyphenyls are also an important structural element in liquid crystals and fluorescent compounds [48][49][50][51][52]. Terphenyls have been previously synthesized by the reaction of aryl- or benzylzinc reagents with functionalized biphenyl

Effects of anion complexation on the photoreactivity of bisureido- and bisthioureido-substituted dibenzobarrelene derivatives

• Heiko Ihmels and
• Jia Luo

Beilstein J. Org. Chem. 2011, 7, 278–289, doi:10.3762/bjoc.7.37

• ], liquid crystals [18], chiral crystals [19][20][21][22][23], or cyclodextrins (CDs) [24][25][26] in such a way that the chiral environment within the binding site has an influence on preferential reaction pathways, thus inducing stereoselective photoreactions. Along these lines, the di-π-methane (DPM

Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

• Baoxiang Gao,
• Hongxia Li,
• Defang Xia,
• Sufang Sun and
• Xinwu Ba

Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26

• oligopeptides can act as useful building blocks for chiral supramolecular liquid crystals [15][16]. Herein, we present the synthesis of amphiphilic dendritic peptides (ADPs) composed of an aspartic acid core and an aliphatic periphery, and their self-assembly which leads not only to organogels but also to

• liquid crystals. Results and Discussion Synthesis and characterization The amphiphilic dendritic peptides were synthesized convergently as depicted in Scheme 1 via standard EDCI coupling of N-carbobenzyloxy-L-aspartic acid and L-aspartic acid dodecyl ester (readily prepared by the esterification of

• characteristic of hexagonal columnar liquid crystals. The conic fan-shaped textures of G3 grow (Figure 6B), and no longer change at 50 °C (Figure 6C). Figure 7 shows the XRD scan for the birefringent phase of G3 at 50 °C. The birefringent phases of G3 were further confirmed as a hexagonal columnar liquid crystal

Symmetry breaking and structure of a mixture of nematic liquid crystals and anisotropic nanoparticles

• Marjan Krasna,
• Matej Cvetko and
• Milan Ambrožič

Beilstein J. Org. Chem. 2010, 6, No. 74, doi:10.3762/bjoc.6.74

• impact of NPs on orientational ordering of LCs for appropriate concentrations of NPs is reminiscent to the influence of quenched random fields which locally enforce a biaxial ordering. Keywords: liquid crystals; nanoparticles; orientational order; quenched disorder; symmetry breaking; Introduction The

• are cases where the host component is a soft material [6]. These materials can then exhibit relatively strong responses, even to local low-energy excitations. Typical representatives of soft materials, with great application potential, are various liquid crystals phases [6]. Their soft character is

• spatially homogeneous structure is gradually attained. However, if impurities are present, they can pin the defects [12][13][14]. Consequently, the domain structure can be stabilized. In this contribution we study numerically a mixture of uniaxial nematic liquid crystals and rod-like NPs using a Lebwohl

Suzuki–Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported N-heterocyclic carbene–palladium complex catalyst

• Guangming Nan,
• Fang Ren and
• Meiming Luo

Beilstein J. Org. Chem. 2010, 6, No. 70, doi:10.3762/bjoc.6.70

• ; recyclable catalyst; Suzuki–Miyaura reaction; Introduction The unsymmetrical biaryls feature in a diverse range of organic compounds, such as natural products, advanced materials, liquid crystals, ligands and molecules of medicinal interest [1][2][3][4]. The palladium-catalyzed Suzuki–Miyaura cross-coupling

Synthesis and crystallographic analysis of meso-2,3-difluoro-1,4-butanediol and meso-1,4-dibenzyloxy-2,3-difluorobutane

• Bruno Linclau,
• Leo Leung,
• Jean Nonnenmacher and
• Graham Tizzard

Beilstein J. Org. Chem. 2010, 6, No. 62, doi:10.3762/bjoc.6.62

• 1,3-C–F bonds are destabilised. As an application, liquid crystals have been prepared containing a vicinal difluoride motif [14][17][18]. Efficient stereodefined synthesis of vicinal difluoride moieties is not straightforward. Direct methods include fluorination of alkenes with F2 [19], XeF2 [20], or

Self-assembled ordered structures in thin films of HAT5 discotic liquid crystal

• Piero Morales,
• Jan Lagerwall,
• Paolo Vacca,
• Sabine Laschat and
• Giusy Scalia

Beilstein J. Org. Chem. 2010, 6, No. 51, doi:10.3762/bjoc.6.51

• compared to the bulk situation, where the same material crystallizes into a polymorphic structure at 68 °C. Keywords: AFM; discotic liquid crystals; hexapentyloxytriphenylene; self-organization; thin films; Introduction Discotic liquid crystals are an interesting type of organic semiconductors that allow

• columns, which then behave like molecular wires. Their good performance makes them promising for use as transistors [3] in electronic circuits, for light emitting diodes [4] and in solar cells [5][6]. Liquid crystals (LCs) possess a long range, even if imperfect, order that is beneficial for creating a

• discotic liquid crystals in micrometer-sized regions of uniform planar alignment. The self-organizing nature of discotics is thus a powerful and promising tool for creating controlled nanometric or micrometric structures. Experimental HAT5 was dissolved in toluene at different concentrations and deposited

The C–F bond as a conformational tool in organic and biological chemistry

• Luke Hunter

Beilstein J. Org. Chem. 2010, 6, No. 38, doi:10.3762/bjoc.6.38

• of functional molecules that exploit these conformational effects will then be presented, drawing from a diverse range of molecules including pharmaceuticals, organocatalysts, liquid crystals and peptides. Keywords: conformation; functional molecules; organofluorine chemistry; stereochemistry

• novel liquid crystals. A distinguishing feature of compounds such as 54 is their stereochemical complexity. It is necessary to control these stereocentres during synthesis so that the conformational properties of different diastereoisomers can be compared. This has been explored with compounds

• liquid crystals. A liquid crystal is a fluid phase in which there is some orientational ordering of the molecules. Liquid crystal display (LCD) technology requires rod-shaped molecules that have a dipole moment perpendicular to the long axis of the molecule, and this is often achieved by incorporating

The subtle balance of weak supramolecular interactions: The hierarchy of halogen and hydrogen bonds in haloanilinium and halopyridinium salts

• Kari Raatikainen,
• Massimo Cametti and
• Kari Rissanen

Beilstein J. Org. Chem. 2010, 6, No. 4, doi:10.3762/bjoc.6.4

• in crystal engineering [18][19], and lately it has widely and successfully applied in other fields of material science, such as in supramolecular separations, liquid crystals, organic semiconductors and paramagnetic materials technologies [20][21]. Recently, the important role of XBs in biological

Competition between local disordering and global ordering fields in nematic liquid crystals

• Matej Cvetko,
• Milan Ambrožič and
• Samo Kralj

Beilstein J. Org. Chem. 2010, 6, No. 2, doi:10.3762/bjoc.6.2

• Department, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia 10.3762/bjoc.6.2 Abstract We study the influence of external electric or magnetic field B on orientational ordering of nematic liquid crystals or of other rod-like objects (e.g. nanotubes immersed in a liquid) in the presence of random

• disordered regime. Memory effects are apparent only in the latter case, i.e. for B < Bc. PACS numbers: 47.51.+a, 47.54.-r, 07.05.Tp, 61.30.-v Keywords: disorder; Imry-Ma theorem; liquid crystals; memory effect; orientational order; Introduction For years there has been a strong interest in the phase and

• structural behavior of randomly perturbed liquid crystals (LCs) [1]. Such systems could be used in various electro-optical applications. On the other hand they represent also an adequate testing ground [2] to study fundamental questions concerning the impact of disorder [3][4][5][6] on various phase and

Looking forward to volume six

• Jonathan Clayden

Beilstein J. Org. Chem. 2010, 6, No. 1, doi:10.3762/bjoc.6.1

• way within the journal, these papers can be viewed together using the “thematic series” tool on the website. Recent series have covered the topical themes of flow chemistry [1], supramolecular chemistry [2] and liquid crystals [3], and further series on carbohydrate chemistry and on organofluorine

Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues

• Aleksandra Jankowiak,
• Piotr Kaszynski,
• William R. Tilford,
• Kiminori Ohta,
• Adam Januszko,
• Takashi Nagamine and
• Yasuyuki Endo

Beilstein J. Org. Chem. 2009, 5, No. 83, doi:10.3762/bjoc.5.83

• B) than for carbocyclic derivatives (C and D). Analysis indicates that this effect may have quadrupolar and conformational origin. Keywords: p-carborane; liquid crystals; structure-property relationship; Introduction During the past decade, we have been investigating mesogenic derivatives of p

• -carboranes A and B (Figure 1) in the context of fundamental and applied studies of liquid crystals and development of new materials for electrooptical applications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. p-Carboranes belong to an extensive family of closo-boranes

• isostructural mesogenic derivatives of p-carboranes (A and B), bicyclo[2.2.2]octane (C), and benzene (D), we have been probing fundamental aspects of structure-property relationships in liquid crystals such as the effect of conformational properties [1][2], the structure of the linking group [5], and tail

Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules

• Matthias Lehmann and
• Jens Seltmann

Beilstein J. Org. Chem. 2009, 5, No. 73, doi:10.3762/bjoc.5.73

• , indicating the alignment of two molecular axes along individual directors in the magnetic field. These observations may be rationalised with larger assemblies of V-shaped molecules isotropically distributed around the direction of the magnetic field. Keywords: biaxial nematics; liquid crystals; phase

• engineering; thiadiazoles; V-shaped mesogens; Introduction Most molecules forming nematic liquid crystals, the nematogens, are based on rod-shaped (calamitic), anisometric cores with peripheral flexible chains along the molecular long axis [1]. Nematic phases are the simplest liquid crystalline mesophases

• of a series of thiadiazoles of general structure II is presented and the successful approach to low temperature, enantiotropic nematic liquid crystals in the family of bent-shaped oligo(phenylene ethynylenes) will be discussed. Results and Discussion Synthesis The shape-persistent arms of the new

Molecular length distribution and the formation of smectic phases

• Nadia Kapernaum,
• C. Scott Hartley,
• Jeffrey C. Roberts,
• Robert P. Lemieux and
• Frank Giesselmann

Beilstein J. Org. Chem. 2009, 5, No. 65, doi:10.3762/bjoc.5.65

• by extensive out-of-layer fluctuations. Keywords: bidispersity; liquid crystals; phase diagrams; smectic phases; structure and dynamics; Introduction The classical (and highly successful) approach to systematically tailor liquid crystal materials for specific applications is the formulation of

Influence of spacer chain lengths and polar terminal groups on the mesomorphic properties of tethered 5-phenylpyrimidines

• Gundula F. Starkulla,
• Elisabeth Kapatsina,
• Angelika Baro,
• Frank Giesselmann,
• Stefan Tussetschläger,
• Martin Kaller and
• Sabine Laschat

Beilstein J. Org. Chem. 2009, 5, No. 63, doi:10.3762/bjoc.5.63

• maximum phase width was observed for the C5 spacer regardless of the terminal group, whereas the hydroxy- and cyano-substituted derivatives 5 and 7, respectively, were non mesomorphic and showed only melting transitions. Keywords: calamitic; liquid crystals; 5-phenylpyrimidines; Introduction A

• tremendous amount of work has been done on calamitic liquid crystals, which has led to applications in the field of LC displays [1]. Among the large family of various calamitic mesogens 2-alkoxy-5-phenylpyrimidines 1 are prominent members due to the fact that the two nitrogen atoms increase the polarity of

• are possible, i.e. 4-, 5-, and 2-phenylpyrimidine, only the latter two are suitable for liquid crystals. Furthermore 5- and 2-phenylpyrimidines differ in their overall conformation. According to ab initio calculation by Barone [2], 2-phenylpyrimidine is almost planar, whereas 5-phenylpyrimidine has a

1-(4-Alkyloxybenzyl)-3-methyl-1H-imidazol-3-ium organic backbone: A versatile smectogenic moiety

• William Dobbs,
• Laurent Douce and
• Benoît Heinrich

Beilstein J. Org. Chem. 2009, 5, No. 62, doi:10.3762/bjoc.5.62

• using the imidazolium ring as a common element, has allowed us to tailor a new set of materials which associate specific functionalities. These functionalities are consequences of the original properties of the component, ionic liquids, liquid crystals and their association in a single compound. The

• ; supramolecular arrangement; Introduction Uniting the properties of ionic derivatives with those of liquid crystals, with their many forms of labile macroscopic ordering, raises interesting prospects [1]. By themselves ionic liquids are organic salts (i.e. totally composed of cations and anions) that are

• , none of these cations are as popular as the imidazolium ion. In particular, the modification of the N,N′ substituents in imidazolium systems is a facile mean of creating various amphotropic liquid crystals. Such imidazolium liquid crystals have especially great potential as ordered reaction media that

Coaxial electrospinning of liquid crystal-containing poly(vinylpyrrolidone) microfibres

• Eva Enz,
• Ute Baumeister and
• Jan Lagerwall

Beilstein J. Org. Chem. 2009, 5, No. 58, doi:10.3762/bjoc.5.58

• special properties (in particular optical) that result from the unique combination of fluidity and long-range order of liquid crystals are interesting from different points of view. On the one hand, the LC can give the fibre new functionality, in particular sensitivity to temperature variations or to the

Saddle-shaped tetraphenylenes with peripheral gallic esters displaying columnar mesophases

• Eugen Wuckert,
• Constanze Hägele,
• Frank Giesselmann,
• Angelika Baro and
• Sabine Laschat

Beilstein J. Org. Chem. 2009, 5, No. 57, doi:10.3762/bjoc.5.57

• was detected. Keywords: columnar mesophases; discotic liquid crystals; tetraphenylene; Introduction Columnar liquid crystals have received increasing interest during the last decade due to their 1D charge transport and self-healing properties, which make them particularly promising candidates for

• anomalous odd-even effect is a more general phenomenon than previously thought. Investigations to extend this concept to other classes of liquid crystals are currently in progress. Experimental General Melting points were measured on a Mettler Toledo DSC822 and are uncorrected. NMR spectra were recorded on

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

• Alessandra Crispini,
• Mauro Ghedini and
• Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

• single molecule to supramolecular network, confirming that metal coordination provides a helpful tool for obtaining multifunctional soft materials. Keywords: coordination complexes; functionality; liquid crystals; metallomesogens; Introduction Recent interest in designing novel soft and functional

• intramolecular interactions [25][26][27][28][29][30]. The high level of functionality integrated into molecular-based electronic systems obtained by incorporating metal centres into selected organic structures [31] supports the design of metal-containing liquid crystals (metallomesogens) as an effective and

• helpful way to expand of the traditional range of technological applications of liquid crystals [32][33][34][35][36][37]. We have been involved for long time in the field of metallomesogens with the synthesis of cyclopalladated rod-like complexes starting from mesogenic azo and azoxybenzenes, confirming

Novel banana-discotic hybrid architectures

• Hari Krishna Bisoyi,
• H. T. Srinivasa and
• Sandeep Kumar

Beilstein J. Org. Chem. 2009, 5, No. 52, doi:10.3762/bjoc.5.52

• crystalline property probably because of the incompatibility of the bent-core with the discotic core. Keywords: bent-core; dimer; discotic; triphenylene; Introduction Liquid crystals are unique functional self-organized soft materials which possess order and dynamics. Recently, banana liquid crystals or

• , smectic and columnar phases. On the other hand, the unique geometry of the columnar mesophase formed by discotic liquid crystals is of great importance not only as models for the study of one-dimensional charge and energy migration in organized systems but also as functional materials for device

• and self-healing of defects owing to their dynamic nature. Furthermore, there has been considerable interest in the field of non-conventional low molar mass liquid crystals, especially in liquid crystal dimers because of their interesting mesomorphic properties. Liquid crystal oligomers serve as ideal

A convenient method for preparing rigid-core ionic liquid crystals

• Julien Fouchet,
• Laurent Douce,
• Benoît Heinrich,
• Richard Welter and
• Alain Louati

Beilstein J. Org. Chem. 2009, 5, No. 51, doi:10.3762/bjoc.5.51

• , differential scanning calorimetry and X-ray diffraction. In addition its lamellar crystal structure, electrochemical behaviour and UV (absorption and emission) properties are reported. Keywords: imidazolium; ionic liquid crystals; Ullman reaction; Introduction Over the past decade extensive studies of ionic

• /hydrophobicity…). Important emerging applications include those in separation and extraction processes, and in various electrochemical devices, such as lithium ion batteries, fuel cells, and capacitors, as well as in synthesis and catalysis [1][2][3][4][5]. Liquid crystals are characterised by both mobility and

• governs the formation of a multitude of supramolecular architectures depending on the temperature (thermotropic liquid crystals) and/or of the solvent (lyotropic liquid crystals) [7][8]. In the case of the thermotropic liquid crystals the arrangements give rise to nematic phases (molecules are aligned

Chiral amplification in a cyanobiphenyl nematic liquid crystal doped with helicene-like derivatives

• Alberta Ferrarini,
• Silvia Pieraccini,
• Stefano Masiero and
• Gian Piero Spada

Beilstein J. Org. Chem. 2009, 5, No. 50, doi:10.3762/bjoc.5.50

• , allows us to extend our knowledge of the molecular origin of the chirality amplification in liquid crystals and to confirm the simple relationship “molecular P-helicity” → “cholesteric P-handedness” for helical-shaped helicene-like derivatives. Keywords: chirality; cholesteric; helical twisting power

• ; helicene; nematic liquid crystal; Surface Chirality model; Introduction Nematic liquid crystals (LCs) are fluid phases formed by anisometric molecules which, though free to rotate as in ordinary liquids, are preferentially aligned along a common axis, called director. The addition of a chiral non-racemic

• variously distributed around the molecular core, allows us to extend our knowledge of the molecular origin of the chirality amplification in liquid crystals. Results and Discussion The enantioselective synthesis as well as the configuration assignment of enantiopure dihydro[5]helicene quinones or

Synthesis of mesogenic phthalocyanine-C₆₀ donor–acceptor dyads designed for molecular heterojunction photovoltaic devices

• Yves Henri Geerts,
• Olivier Debever,
• Claire Amato and
• Sergey Sergeyev

Beilstein J. Org. Chem. 2009, 5, No. 49, doi:10.3762/bjoc.5.49

• example of LC phthalocyanine-C60 dyads. Keywords: donor–acceptor dyad; fullerene; liquid crystals; phthalocyanine; phthalonitrile; Introduction Among sustainable energy technologies, photovoltaic (PV) conversion of solar energy is considered as a promising solution. Although currently the market is

Progress in liquid crystal chemistry

• Sabine Laschat

Beilstein J. Org. Chem. 2009, 5, No. 48, doi:10.3762/bjoc.5.48

• Sabine Laschat Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany 10.3762/bjoc.5.48 Since their discovery in 1888 by the botanist Friedrich Reinitzer, who studied the melting behavior of cholesteryl benzoates, liquid crystals have developed from

• a mere curiosity to a highly interdisciplinary research field, with LC displays being the most important application to date [1][2]. However, besides the use of thermotropic liquid crystals for display technology many other applications will probably be on the market in the near future, such as

• diverse topics such as phthalocyanine-fullerene hybrid materials for photovoltaic devices, functional metallomesogens, coaxial electrospinning of liquid crystal-containing microfibers, banana-discotic hybrid systems, ionic liquid crystals, relations between molecular length distribution and formation of

DBFOX- Ph/metal complexes: Evaluation as catalysts for enantioselective fluorination of 3-(2-arylacetyl)-2-thiazolidinones

• Takehisa Ishimaru,
• Norio Shibata,
• Dhande Sudhakar Reddy,
• Takao Horikawa,
• Shuichi Nakamura and
• Takeshi Toru

Beilstein J. Org. Chem. 2008, 4, No. 16, doi:10.3762/bjoc.4.16

• electrophilic fluorination represents an important and straightforward strategy for C-F bond formation at a carbon stereocenter, providing easy access to chiral fluoro-organic compounds [1][2]. Due to the significance of chiral fluoro-organic compounds, such as fluorinated quinolones [3][4] and liquid crystals