Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

• Gareth L. Nealon,
• Romain Greget,
• Cristina Dominguez,
• Zsuzsanna T. Nagy,
• Daniel Guillon,
• Jean-Louis Gallani and
• Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

• addressable 2-D and 3-D arrangements exhibiting high processability and self-healing properties. Herein, we review the developments in the field of discrete thermotropic liquid-crystalline nanoparticle hybrids, with special emphasis on the relationship between the nanoparticle morphology and the nature of the

• morphology (size, shape and roughness) and can be manipulated by coating with suitable structure-directing agents. Amongst the techniques used to assemble NPs, self-assembly methods show immense promise towards achieving the ambitious results expected from the field of nanotechnology research [23]. Liquid

• surface chemistry and morphology characteristics of the NP under investigation, ensuring a suitable anchoring group and structure-directing groups are present in the molecular structure. In the case of Au NPs, which are by far the most extensively investigated, there are two main methods used for the

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

• Alicja Schlange,
• Antonio Rodolfo dos Santos,
• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2011, 7, 1412–1420, doi:10.3762/bjoc.7.165

• transportation in comparison to hydrogen. At present, factors such as low power densities and high material costs, especially of the electrode, are the main challenges in widespread commercialization of DMFCs. Several research groups have shown that there is a clear correlation between the morphology of a carbon

• preparation method is one of the most important factors determining the morphology and activity of Pt catalysts supported by carbon nanotubes. Short heating times and short reaction times are essential for the reduction of highly active platinum particles on nanotube supports. The proposed continuous

Air-stable, recyclable, and time-efficient diphenylphosphinite cellulose-supported palladium nanoparticles as a catalyst for Suzuki–Miyaura reactions

• Qingwei Du and
• Yiqun Li

Beilstein J. Org. Chem. 2011, 7, 378–385, doi:10.3762/bjoc.7.48

• morphology of Cell–OPPh2–Pd0 and Cell–OPPh2 was studied by SEM and TEM. A clear change in morphology is observed after anchoring palladium onto the polymer support (Figure 3). The TEM image of the Cell–OPPh2–Pd0 catalyst shows that the average size of the nanopalladium particles is in the range of 4–15 nm

• (Figure 4a). The TEM image of the used catalyst indicates that the size and morphology of the nanopalladium has suffered slightly from agglomeration in the recovered catalyst after being reused six times (Figure 4b). Suzuki–Miyaura cross-coupling reactions To explore the efficiency of the

Protonation and deprotonation induced organo/hydrogelation: Bile acid derived gelators containing a basic side chain

• Uday Maitra and
• Arkajyoti Chakrabarty

Beilstein J. Org. Chem. 2011, 7, 304–309, doi:10.3762/bjoc.7.40

• /water hydrogel (normally cooled), inter-connected fibres (Figure 5a) and some needle-like microcrystallites (Figure 5b) were observed under a polarizing optical microscope. Interestingly, there were two types of morphology observed in the SEM micrographs: Normally-cooled gels showed finer fibres as

• -stability of the hydrogel. However, it was also found that the organogel showed high thermal stability and the nanoscale morphology represented fibres of diameters ranging from 80 nm to 1 μm. The hydrogel had comparatively lower thermal stability and showed different morphologies on sonication induced

Synthesis and self-assembly of 1-deoxyglucose derivatives as low molecular weight organogelators

• Guijun Wang,
• Hao Yang,
• Sherwin Cheuk and
• Sherman Coleman

Beilstein J. Org. Chem. 2011, 7, 234–242, doi:10.3762/bjoc.7.31

• 9A formed fibrous assemblies (Figure 3A, Figure 3B). Compound 9B showed tubular assemblies (Figure 3C) and more straight cylindrical tube or ribbons (Figure 3D) at different areas. Compound 15B formed gels more efficiently at 4 mg/mL in the ethanol/water mixture. The morphology of the assembly showed

Exceptionally small supramolecular hydrogelators based on aromatic–aromatic interactions

• Junfeng Shi,
• Yuan Gao,
• Zhimou Yang and
• Bing Xu

Beilstein J. Org. Chem. 2011, 7, 167–172, doi:10.3762/bjoc.7.23

• , which agrees with the morphology as revealed by TEM (Figure 4). Figure 4 shows the TEM images of the matrices of gels I to IV. The phenylalanine based hydrogelator self-assemble into nanofibers that physically cross-link to form a fibrous network as the matrix of hydrogel. For example, the fibers in gel

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• many cases on the nanoparticles themselves, i.e., size and size distribution or morphology, and not on the characteristics of the polymer chains (for a given polymer). Functionalized polymers can be obtained by the homopolymerization of a functional monomer or its copolymerization with another (non

• [28]. Thus water-soluble poly(hydroxy vinyl ether)s were copolymerized with oil-soluble maleate esters to yield polymer particles with capsular morphology as shown in Figure 2. While the formation of (hydrophilic) functionalized particles is straightforward in inverse miniemulsions, it most often

• encapsulation of ibuprofen [115]. Interfacial polyaddition in inverse miniemulsions is becoming especially popular since it allows the encapsulation of hydrophilic substances in various polymeric capsules. The method allows the formation of particles with capsular morphology consisting of a liquid core and a

Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator?

• Peter C. Griffiths,
• David W. Knight,
• Ian R. Morgan,
• Amy Ford,
• James Brown,
• Ben Davies,
• Richard K. Heenan,
• Stephen M. King,
• Robert M. Dalgliesh,
• John Tomkinson,
• Stuart Prescott,
• Ralf Schweins and
• Alison Paul

Beilstein J. Org. Chem. 2010, 6, 1079–1088, doi:10.3762/bjoc.6.123

• ranges of gelator concentration (5 < Cgelator < 50 mg ml−1) and temperature (25 < T < 55 °C), this representing the poorest performance of the gelator. Representative SANS data are presented in Figures 2–6 from which the morphology of the structures can be extracted in terms of the nature of the solvent

• any interaction between the structures – to ascertain whether the data may be analyzed merely in terms of their morphology or if there is an additional contribution from inter aggregate correlations. This is most easily assessed by recording the scattering from a series of gels as a function of the

• the data analysis to ignore incorporation of a term describing an interaction between the aggregates. Further, one may conclude that the changes in scattering arise from an increase in the number of structures, with perhaps subtle changes in their size or morphology (at least over this range), i.e

Self-assembly and semiconductivity of an oligothiophene supergelator

• Pampa Pratihar,
• Suhrit Ghosh,
• Vladimir Stepanenko,
• Sameer Patwardhan,
• Ferdinand C. Grozema,
• Laurens D. A. Siebbeles and
• Frank Würthner

Beilstein J. Org. Chem. 2010, 6, 1070–1078, doi:10.3762/bjoc.6.122

• studies of trialkoxybenzamide-functionalized quaterthiophene derivative T1 (Scheme 1). We also present our initial results on the morphology of blends of this electron-rich p-type semiconducting T1 with the well-known n-type semiconductor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Results and

• concentration of 5 x 10−5 M. Studies on blends of T1 with PCBM The fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is a well-known n-type semiconductor and its blends with various electron-donor materials have been extensively used in solar cell devices [24]. The morphology of the blend

• of donor and acceptor materials plays a prominent role in device performance [25]. Recently, we reported that a n-type perylene bisimide organogelator exhibits photovoltaic activity with a p-type semiconducting polymer [26]. In this work, as an initial study we characterized the morphology of a

Differences between β-Ala and Gly-Gly in the design of amino acids-based hydrogels

• Andreea Pasc,
• Firmin Obounou Akong,
• Sedat Cosgun and
• Christine Gérardin

Beilstein J. Org. Chem. 2010, 6, 973–977, doi:10.3762/bjoc.6.109

• method at the same concentration, and was higher than the sol-to-gel transition temperature of the 2% w/v sample. On drying, the fibres aggregate to form larger fibre bundles as shown in Figure 4. The morphology of the gel was observed by scanning electron microscopy (SEM, Figure 4). The micrographs show

Towards racemizable chiral organogelators

• Jian Bin Lin,
• Debarshi Dasgupta,
• Seda Cantekin and
• Albertus P. H. J. Schenning

Beilstein J. Org. Chem. 2010, 6, 960–965, doi:10.3762/bjoc.6.107

• transition is associated with gel melting and/or gel formation. When the racemate (R-3 = S-3 = 2.5 mM) was heated and cooled to room temperature, precipitation was observed (Figure 2b). The morphology of the organogel was further characterized by field emission scanning electron microscopy (FESEM) as well as

• at which, infinite percolation is achieved within a network system, although microgel network structures can still be observed below the CGC. The fibers have an average diameter is 60 ± 10 nm and lengths of tens of micrometers suggesting effective anisotropic growth. The morphology of the R-3

• ; d) the surface morphology of the dried gel obtained from R-3 in octane (15 mM) observed by FESEM. a) Concentration-dependent 1H NMR spectra of R-3 in cyclohexane-d12 and b) the shift of N–H signal of amide group versus concentration. The evolution of ln(ee × 100) for the racemization of R-3 (1 mM

Oxalyl retro-peptide gelators. Synthesis, gelation properties and stereochemical effects

• Janja Makarević,
• Milan Jokić,
• Leo Frkanec,
• Vesna Čaplar,
• Nataša Šijaković Vujičić and
• Mladen Žinić

Beilstein J. Org. Chem. 2010, 6, 945–959, doi:10.3762/bjoc.6.106

• that for the (S,R)-bis(LeuLeu) 1a and (S,S)-bis(LeuLeu) 1a retro-peptidic gelators, the stereochemistry has a decisive impact on their gelation effectiveness and final gel morphology in their water/DMSO gels. Results and Discussion Synthesis of oxalyl retro-dipeptidic gelators A series of chiral bis

• gelation properties, self-assembly motifs and gel morphology. The influence of stereochemistry on self-aggregation and morphology was studied with 1a–c combining different configurations of Leu: (S,R)-1a, b, c and (R,S)-1a, b, c. Gelation properties of pure enantiomers (S,S)-1b and (S,R)-1b are compared

• previously, TEM investigations of bis(amino acid)oxalamide gels revealed in most cases formation of very dense networks consisting of heavily entangled tiny fibers with diameters in the range of 10–20 nm [58][59][60]. A similar morphology was observed for the bis(PhePhe)-5a-EtOH gel (fiber d’s 6–20 nm) and

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• contribution of the different interactive forces and an insight into the 3D-morphology of supramolecular aggregates [20][21][22]. In this context, low molecular weight hydrogels (LMWH) are of greater importance compared to polymeric ones as the former (i) can have diversified supramolecular morphology by

• simply a macroscopic manifestation of the self-assembled aggregation at the molecular level due to the optimum combination of hydrophilic and hydrophobic interactions between molecules [12]. The formation, nature and morphology of these supramolecular 3D-networks are primarily dictated by the

• formation of three dimensional higher ordered structures during self-assembled hydrogelation was investigated by field emission scanning electron microscopy (FESEM). Morphology of the dried xerogels showed the formation of different supramolecular structures that are involved in the gelation process of 1

Chiral gels derived from secondary ammonium salts of (1R,3S)-(+)-camphoric acid

• Tapas Kumar Adalder,
• N. N. Adarsh,
• Ravish Sankolli and
• Parthasarathi Dastidar

Beilstein J. Org. Chem. 2010, 6, 848–858, doi:10.3762/bjoc.6.100

• 1,2-dichlorobenzene xerogels of DBAMC 6, whereas relatively short plate like morphology was observed in the nitrobenzene xerogel of DBUAMC 3. Understandably, the solvent molecules are immobilized in these networks to form gel. To prove structure-property correlation in these gelators, we tried to

New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin

• Otman Otman,
• Paul Boullanger,
• Eric Drockenmuller and
• Thierry Hamaide

Beilstein J. Org. Chem. 2010, 6, No. 58, doi:10.3762/bjoc.6.58

• attention because of their potential since they represent attractive alternatives to conventional pharmaceutical applications. In addition, the size, morphology and composition of the polymer particles can be tuned to optimize the drug release kinetics in order to reduce, e.g., toxicity and improve efficacy

• . These parameters are closely connected. For instance, the chemical composition of the polymer matrix may affect the particle morphology because of thermodynamic interactions between the hydrophobic drug and the polymer. Whatever the drug delivery system, surfactants, and in particular polymer non-ionic

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

• the director in the linear structures. The upper and lower images were obtained with crossed polarizers while the middle one was taken without the analyzer to show the complete sample morphology. AFM scan of a thick rope, of similar size to the linear structures observed by optical microscopy. AFM

C-Arylation reactions catalyzed by CuO-nanoparticles under ligand free conditions

• Mazaahir Kidwai,
• Saurav Bhardwaj and
• Roona Poddar

Beilstein J. Org. Chem. 2010, 6, No. 35, doi:10.3762/bjoc.6.35

• differences which have been shown in the TEM image. The number of reactive sites on the surface is small in the case of larger crystallites and considerably greater in the case of smaller crystallites (Figure 1). To investigate further the surface morphology of CuO-nanoparticles, powder XRD and TEM images

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

• counter ions’ morphology. Results and Discussion Synthesis and characterization Our molecules are based on an organic calamitic structure in which a polar rigid group (methylimidazolium head) is associated to a flexible aliphatic chain with 8 to 16 carbons. The syntheses of all the compounds presented in

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

• modification of the target, e.g. by using two parallel electrodes as collector [8]. A recent review on different electrospinning setup designs is given in [9]. The morphology and final diameter of the resulting fibres can be influenced by several parameters, which can be divided into two categories: intrinsic

• sample in Figure 3e. The smeared-out morphology in this last texture strongly suggests that the fibre still contained substantial amounts of solvent upon collection. The liquid state of such a deposited material then allowed a post-collection morphology change, ruining the desired coaxial fibre structure

• result when considering the flow geometry of a smectic phase. By varying the relation between the flow rate of the outer polymer solution and the flow rate of the LC the morphology of the core could be changed stepwise from discontinuous to very thin but continuous with overall fibre thicknesses

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

• transported to the electrodes. Hence, a critical issue in bulk heterojunction PV devices is the control of morphology of materials, in order to provide both the efficient exciton generation and the rapid charge carrier transport. The logical step in the development of this architecture is “molecular

Gold film- catalysed benzannulation by Microwave- Assisted, Continuous Flow Organic Synthesis (MACOS)

• Gjergji Shore,
• Michael Tsimerman and
• Michael G. Organ

Beilstein J. Org. Chem. 2009, 5, No. 35, doi:10.3762/bjoc.5.35

• assessment of different types of metal films for their utility in benzannulation. The morphology of Cu, Pd, Ag, and Au films can be compared in the scanning electron microscopy (SEM) images in Figure 2. The films are generally prepared in a reducing environment (see Experimental), thus they are expected to

New diarylmethanofullerene derivatives and their properties for organic thin- film solar cells

• Daisuke Sukeguchi,
• Surya Prakash Singh,
• Mamidi Ramesh Reddy,
• Hideyuki Yoshiyama,
• Rakesh A. Afre,
• Yasuhiko Hayashi,
• Hiroki Inukai,
• Tetsuo Soga,
• Shuichi Nakamura,
• Norio Shibata and
• Takeshi Toru

Beilstein J. Org. Chem. 2009, 5, No. 7, doi:10.3762/bjoc.5.7

• LUMO energy level which leads to an increase of the open-circuit voltage (Voc) values of the solar cell. These diarylmethanofullerenes have long alkyl chain(s) to increase the solubility and hopefully to cause the interaction with the donor P3HT polymer, being related to the morphology of the

• values as compared with lower Voc values for the cells fabricated with other derivatives 1d, 1f–1k, and 2. The reason is not clear but the lower Voc values may be a consequence of negative effects such as morphology problems relating to inefficient charge transfer or charge separation. A more detailed

Synthesis of thienyl analogues of PCBM and investigation of morphology of mixtures in P3HT

• Fukashi Matsumoto,
• Kazuyuki Moriwaki,
• Yuko Takao and
• Toshinobu Ohno

Beilstein J. Org. Chem. 2008, 4, No. 33, doi:10.3762/bjoc.4.33

• thieno[3,2-b]thiophene (3c, 3d) were synthesized and characterized. The morphology of the thin films prepared from the mixtures of these methanofullerenes with regioregular poly(3-hexylthiophene) (P3HT) was investigated by AFM measurement and UV-Vis absorption spectroscopy. A solubility test of these

• methanofullerenes was performed by using dichloromethane as a solvent. es-TThCBM (3d) exhibited 1.4 times greater solubility in dichloromethane than PCBM. Keywords: fullerene; morphology; organic fullerenes; PCBM; photovoltaic cell; Introduction The demand for inexpensive, renewable energy sources continues to

• crystallinity of the polymer [13][14], and controlling the growth rate of the organic film [15][16]. These studies reported that the morphology of the active layer is a critical factor that determines the device efficiency. Investigations have been performed for exploring new donor materials for bulk

Stereoselective synthesis of (2S,3S,4Z)-4-fluoro- 1,3-dihydroxy- 2-(octadecanoylamino)octadec- 4-ene, [(Z)-4-fluoroceramide], and its phase behavior at the air/water interface

• Gergana S. Nikolova and
• Günter Haufe

Beilstein J. Org. Chem. 2008, 4, No. 12, doi:10.3762/bjoc.4.12

• -fluorinated parent compounds, and therefore to higher stability of the monolayer formed at the air/water interface. This unique behavior of the 4-fluoroceramide molecules provides the basis for further development of the morphology of the monolayer and possible formation of multi-layers, as well as for