The arene–alkene photocycloaddition

• Ursula Streit and
• Christian G. Bochet

Beilstein J. Org. Chem. 2011, 7, 525–542, doi:10.3762/bjoc.7.61

• can be changed [45]. The linear and angular isomer names are derived from the opening of the cyclopropane ring to afford linearly and angularly fused triquinanes. Asymmetric meta photocycloadditions The meta photocycloaddition has the potential to convert planar (thus achiral) molecules into three

• -dimensional chiral molecules. It is therefore not surprising that many attempts have been made to render this process enantioselective. The main strategy in this perspective is the introduction of a chiral center directly on the tether in an intramolecular photocycloaddition, and to carry out the reaction in

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

• properties. Notably, compound 6 can undergo cis/trans-isomerization upon UV irradiation. Keywords: aromatic–aromatic interaction; cinnamoyl; hydrogel; hydrogelator; supramolecular; Introduction Gels formed by three-dimensional, elastic networks to encapsulate a liquid [1], have many useful properties (e.g

Expanding the gelation properties of valine-based 3,5-diaminobenzoate organogelators with N-alkylurea functionalities

• Hak-Fun Chow and
• Chin-Ho Cheng

Beilstein J. Org. Chem. 2010, 6, 1015–1021, doi:10.3762/bjoc.6.114

• those of the shorter ones. Keywords: amino acids; hydrophobic effect; organogelators; self-assembly; urea; Introduction Organic gelators are an interesting group of molecules that are able to form a non-covalent three dimensional network with a particular solvent system. The ultimate result is the

Insights into the mechanical properties of a silicone oil gel with a ‘latent’ gelator, 1-octadecylamine, and CO₂ as an ‘activator’

• Emiliano Carretti,
• Mathew George and
• Richard G. Weiss

Beilstein J. Org. Chem. 2010, 6, 984–991, doi:10.3762/bjoc.6.111

• fractions of a liquid. The structures of the assemblies almost always consist of one-dimensional objects (usually fibers, rods or nanotubes) that interact to form three-dimensional self-assembled fibrillar networks (SAFINs) [1][2][3]. This interest is motivated by the search for fundamental information on

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

• microscopy (FESEM), atomic force microscopy (AFM), photoluminescence, FTIR studies, X-ray diffraction (XRD) and 2D NOESY experiments were carried out to elucidate the different non-covalent interactions responsible for the self-assembled gelation. The formation of three-dimensional supramolecular aggregates

• origin [18] (poly(acrylic acid) and derivatives, polypeptides and small molecules). This fascinating class of materials results from the spontaneous self-assembly of polymeric/non-polymeric molecules that lead to the formation of supramolecular three dimensional (3D) networks with interstitial space for

• 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

• then start to entangle themselves to form a three dimensional network within which the solvent molecules are immobilized by capillary force interactions resulting in gel formation. The elegance of a LMOG lies in the reversible nature of the gel forming network and it is possible to tune the physical

Organic gelators and hydrogelators

• Jean-Pierre Desvergne

Beilstein J. Org. Chem. 2010, 6, 846–847, doi:10.3762/bjoc.6.99

• liquid) which behaves as a visco-elastic material (soft matter) due to the immobilization of solvent molecules in a three-dimensional network. This network results from the self-assembly of the gelling agent into fibres via non-covalent interactions such as hydrogen bonding, π–π stacking, van der Waals

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

• ordering in the nematic LC phase [18][19]. Results and Discussion Model The three-dimensional (3D) spin model simultaneously describes the orientational field of a LC molecule and the dimensionless magnetization of the magnetic component. We henceforth refer to these elements as nematic spins and magnetic

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

• sites. Differences between these types of ligands also show up in the kinetics of complex formation. The conformationally rigid cryptands complex slower than coronands and these in turn are slower than the flexible podands. In contrast to crown ethers, the three dimensional cryptands display peak

• the ring [149]. Binding strengths for 18 are slightly higher than for 17. Compared to (S,S)-19, macrobicyclic (S,S,S,S)-18 shows an improved stereoselective recognition towards NEA (1-naphthyl-ethyl ammonium salt, 20a) in its three-dimensional cavity. A large difference in stabilities between the

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• modelling techniques. The results have shown that, in many cases, the three-dimensional structure of naturally occurring biomolecules can be mimicked by carbopeptoids and pseudoamide-linked oligomeric surrogates. Nevertheless, further investigations are required to clarify the structure-activity

Synthesis and properties of calix[4]arene telluropodant ethers as Ag⁺ selective sensors and Ag⁺, Hg²⁺ extractants

• Yang Lu,
• Yuanyuan Li,
• Song He,
• Yan Lu,
• Changying Liu,
• Xianshun Zeng and
• Langxing Chen

Beilstein J. Org. Chem. 2009, 5, No. 59, doi:10.3762/bjoc.5.59

• ; Introduction There is much interest in the development of compounds that selectively respond to specific metal ions for use as ion sensors. As the third generation of supramolecule, benefiting from their three-dimensional structures and easy chemical modification both at the upper- and lower-rims as well as

Review of “Stereochemistry Workbook, 191 Problems and Solutions” by K.-H. Hellwich and C. D. Siebert

• Roald Hoffmann

Beilstein J. Org. Chem. 2009, 5, No. 38, doi:10.3762/bjoc.5.38

• . Molecules have shapes. The logic of isomerism, in all its manifestations, the life-and-death-determining necessity of describing three-dimensional geometry, our representational struggles to do so – these define the beauty of chemistry.

A hydrogen- bonded channel structure formed by a complex of uracil and melamine

• Reji Thomas and
• G. U. Kulkarni

Beilstein J. Org. Chem. 2007, 3, No. 17, doi:10.1186/1860-5397-3-17

• triply hydrogen-bonded melamine-uracil pairs. Three-dimensional packing of melamine and uracil molecules. Molecules under discussion. Crystal structure data. List of intermolecular interactions in melamine-uracil adduct Supporting Information Supporting Information File 22: The data provided represent

• different, in shape and dimension. This clearly indicates the role of the uracil molecule in directing the shape of the channel structure. In conclusion, we have illustrated the molecular recognition process of melamine with nucleobase uracil. We have also established the presence of channels, in the three

• -dimensional supramolecularly hydrogen-bonded structure of this adduct. (a) ORTEP drawing of the asymmetric unit of the 1:1 molecular complex of uracil and melamine. (b) Unique hydrogen bonds present in the complex. (a) Molecular chain formed by melamine and uracil molecules, (b) the aperture formed by the

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

• David O'Hagan,
• Henry S. Rzepa,
• Martin Schüler and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2006, 2, No. 19, doi:10.1186/1860-5397-2-19

• determines the three dimensional structure of the unit cell. The threo-19 diastereoisomer was prepared by a similar aryl oxidation reaction on a diastereomerically pure sample of threo-13 and this allowed crystallisation of a sample of racemic threo-19. The X-ray structure in Figure 6 shows the molecule in

Colchitaxel, a coupled compound made from microtubule inhibitors colchicine and paclitaxel

• Karunananda Bombuwala,
• Thomas Kinstle,
• Vladimir Popik,
• Sonal O. Uppal,
• James B. Olesen,
• Jose Viña and
• Carol A. Heckman

Beilstein J. Org. Chem. 2006, 2, No. 13, doi:10.1186/1860-5397-2-13

• for three-dimensional cell phenotypes, based on computer-assisted microscopy and sophisticated classification methods, shape data from treated cells were classified by reference to a cell line that became oncogenically transformed over a prolonged course of in vitro culture. Colchicine-treated cells

• ) made from a three-dimensional image. The VROs reconstructed from laser confocal scanning microscopy are shown in Supplemental data. In both untreated and treated cells, the + end 'comets' were concentrated near the cell edge and descended in arc-like patterns toward the substratum. In untreated cells

• , Pittsburgh, PA). The resulting three-dimensional images are displayed in Quickview on Apple Macintosh or Dell PC microcomputers. Microtubule arrangement as visualized by immunofluorescence localization of β-tubulin. Cells were treated with: A) 2 μM Colchitaxel, B) 12 μM Colchitaxel, or C) solvent vehicle