Impact of cyclodextrins on the behavior of amphiphilic ligands in aqueous organometallic catalysis

• Hervé Bricout,
• Estelle Léonard,
• Christophe Len,
• David Landy,
• Frédéric Hapiot and
• Eric Monflier

Beilstein J. Org. Chem. 2012, 8, 1479–1484, doi:10.3762/bjoc.8.167

• complexes and aggregates was a consequence of the competitive equilibria of CD/phosphane complexation and phosphane self-assembly to form micelles. The surface activity of the four studied phosphanes has already been the subject of investigations [7][8]. Phosphanes 1–4 proved to be very surface active as

Cyanoethylation of the glucans dextran and pullulan: Substitution pattern and formation of nanostructures and entrapment of magnetic nanoparticles

• Kathrin Fiege,
• Heinrich Lünsdorf,
• Sevil Atarijabarzadeh and
• Petra Mischnick

Beilstein J. Org. Chem. 2012, 8, 551–566, doi:10.3762/bjoc.8.63

• -forming qualities of cyanoethylpullulan [10]. Partial hydrophobization of polysaccharides by the introduction of nonpolar residues enables nanostructuring by self-assembly of these compounds. Heinze et al. demonstrated that hydrophobic dextran derivatives form spherical particles on the nanometer scale

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

• 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

• observed. Columnar ordering of pseudospherical cores functionalised with laterally substituted mesogens has been observed previously for liquid-crystalline silsesquioxanes [72][73][74], indicating that this self-assembly motif may prove to be quite general. Importantly, this work demonstrated that the

Self-assembly of Ru₄ and Ru₈ assemblies by coordination using organometallic Ru(II)₂ precursors: Synthesis, characterization and properties

• Sankarasekaran Shanmugaraju,
• Dipak Samanta and
• Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2012, 8, 313–322, doi:10.3762/bjoc.8.34

• Sankarasekaran Shanmugaraju Dipak Samanta Partha Sarathi Mukherjee Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560 012, India. Fax: 91-80-2360-1552; Tel: 91-80-2293-3352 10.3762/bjoc.8.34 Abstract Coordination-driven self-assembly of binuclear half

• tetranuclear rectangular geometry with the dimensions of 5.53 Å × 12.39 Å. Furthermore, the photo- and electrochemical properties of these newly synthesized assemblies have been studied by using UV–vis absorption and cyclic voltammetry analysis. Keywords: cages; macrocycles; ruthenium(II); self-assembly; self

• -sorting; Introduction Self-assembly of metal-based molecular architectures through coordination has emerged as an active field of research as large numbers of intricate structural motifs can easily be derived in a single step from predesigned molecular building units. In the last two decades several

Synthesis of multivalent host and guest molecules for the construction of multithreaded diamide pseudorotaxanes

• Nora L. Löw,
• Egor V. Dzyuba,
• Boris Brusilowskij,
• Lena Kaufmann,
• Elisa Franzmann,
• Wolfgang Maison,
• Emily Brandt,
• Daniel Aicher,
• Arno Wiehe and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2012, 8, 234–245, doi:10.3762/bjoc.8.24

• these concepts are not only molecular recognition and the noncovalent bonds themselves, but also self-assembly, self-sorting, templation and multivalent binding [1][2][3][4][5][6][7][8]. Consequently, the reductionist investigation of synthetic supramolecules can help us to understand biological systems

Computational evidence for intramolecular hydrogen bonding and nonbonding X···O interactions in 2'-haloflavonols

• Tânia A. O. Fonseca,
• Matheus P. Freitas,
• Rodrigo A. Cormanich,
• Teodorico C. Ramalho,
• Cláudio F. Tormena and
• Roberto Rittner

Beilstein J. Org. Chem. 2012, 8, 112–117, doi:10.3762/bjoc.8.12

• interactions; theoretical calculations; Introduction Intermolecular hydrogen bonding (HB) is an interaction governing self-assembly and is responsible for the architecture and organization of molecular aggregates [1], and also ligand–receptor interactions that are responsible for the bioactivity of compounds

Impact of the level of complexity in self-sorting: Fabrication of a supramolecular scalene triangle

• Kingsuk Mahata and
• Michael Schmittel

Beilstein J. Org. Chem. 2011, 7, 1555–1561, doi:10.3762/bjoc.7.183

• various scalene triangles. It turned out that the self-sorting system with a higher level of complexity was far superior to less complex sorting algorithms. Keywords: copper; metallosupramolecular chemistry; phenanthroline; self-assembly; self-sorting; Introduction Self-assembly guided by self-sorting

• attributed to [Cu2Zn(5)(6)(7)](OTf)3+, and the doubly charged one at m/z = 1481.1 to [Cu2Zn(5)(6)(7)](OTf)22+. All peaks were isotopically resolved, showing full agreement with the theoretically expected isotopic distribution. To corroborate the clean self-assembly process, we carefully examined the DOSY and

• the 1H NMR (Figure 3b), but the many signals in the region 2.5–4.0 ppm suggest formation of several species. Thus, a comparison among the NMR spectra nicely demonstrated that the self-assembly process was only clean in the case of the mixed-metal scenario, whereas the situation turned out to be

Supramolecular chemistry II

• Christoph A. Schalley

Beilstein J. Org. Chem. 2011, 7, 1541–1542, doi:10.3762/bjoc.7.181

• sciences on the other. In the life sciences, the networks of noncovalent interactions between the constituents of cells, for example, have shifted into the current focus. Self-assembly, templation, self-sorting and multivalent binding all contribute to setting up the extremely complex architecture of a

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

• properties, such as stimuli sensitivity. Their self-assembly in nanoscale superstructures are likely to have important implications in accessing functional nanomaterials [1]. The types of superstructures generated by the SAFINs (Self-Assembled Fibrillar Networks) include fibres, rods, and ribbons. Such self

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

• sugar headgroup towards self-assembly, we synthesized a series of 1-deoxyglucose analogs, and examined their gelation properties in several solvents. Several long chain esters, including diacetylene containing esters, and aryl esters exhibited gelation in ethanol, aqueous ethanol, or aqueous DMSO. The

• synthesis and characterization of these novel analogs are reported. Keywords: 1,5-anhydroglucitol; carbohydrate; hydrogelator; organogelator; self-assembly; Introduction In recent years, the field of low molecular weight gelators (LMWGs) has received a great deal of attention. LMWGs are an interesting

• class of small molecules that can form reversible supramolecular gels in organic solvents or aqueous solutions [1][2][3][4][5][6][7][8][9]. Non-covalent interactions such as hydrogen bonding, hydrophobic interactions, and π–π stacking are the main driving forces for the self-assembly of the gelators

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

• ; liquid crystal; organogels; Introduction Peptide self-assembly has drawn a significant attention due to potential applications, especially in the fields of biomedicine and bionanotechnology [1][2][3]. Programmed self-assembly of peptides into highly ordered nanostructures creates biomaterials that

• regions on their outer surface [6][7]. The self-assembly of amphiphilic oligopeptide systems is thus emerging as a particularly powerful strategy to direct the self-assembly of relatively simple peptide building blocks toward sophisticated nanostructures [8]. Furthermore, the natural amino acid based

• dendrons or dendrimers are of great significance because of their similarity to proteins in composition and topology [9][10][11], as well as their architectural difference from currently prevalent linear model peptides. However, little attention has been paid to the self-assembly of natural amino acid

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

• less explored. We have shown that aromatic–aromatic interactions induce the self-assembly of glycopeptides [30] or pentapeptidic derivatives [31] in water to form nanofibers and supramolecular hydrogels. These results, together with the supramolecular hydrogelators made from dipeptide conjugates with

• fluorenyl or naphthyl groups, clearly support the simple notion that aromatic–aromatic interactions in water may direct the formation of hydrogen bonding and would be useful for the supramolecular self-assembly of small molecules in water. However, despite the progress noted above, an important question

• still remains to be answered: What is the minimal set of aromatic–aromatic interactions and hydrogen bonding for molecular self-assembly in water to produce supramolecular nanofibers and hydrogels? About a decade ago, Menger [32] and coworkers showed that an aroyl L-cystine derivative, which has 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

• research. Keywords: gelation; inelastic neutron spectroscopy; low molar mass organogelator; neutron scattering; neutron spin-echo scattering; self-assembly; Introduction A detailed, molecular level understanding of the fundamental aspects of the spontaneous self-assembly and network formation of low

• ., gelation is akin to the simple self-assembly process demonstrated by surfactants, and is a consequence of a cooperative process. Given the morphology of the scatterers, this is most likely to arise due to growth along the long axis (elongation) of the structures. An analysis protocol has therefore been

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

• (present address) Opto-Electronic Materials Section, Delft Chem Tech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands 10.3762/bjoc.6.122 Abstract A bis(trialkoxybenzamide)-functionalized quaterthiophene derivative was synthesized and its self-assembly properties in solution

• electron-rich quaterthiophene derivative with the electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) revealed a nanoscale segregated assembly of the individual building blocks in the blend. Keywords: charge transport; hydrogen bonding; oligothiophene; organogel; self-assembly

• ; Introduction Self-assembly provides a spontaneous pathway to generate higher-order structures from suitably designed building blocks by virtue of specific intra and intermolecular non-covalent interactions [1]. The development of such building blocks containing various functional π-systems has attracted much

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

Redox-active tetrathiafulvalene and dithiolene compounds derived from allylic 1,4-diol rearrangement products of disubstituted 1,3-dithiole derivatives

• Filipe Vilela,
• Peter J. Skabara,
• Christopher R. Mason,
• Thomas D. J. Westgate,
• Asun Luquin,
• Simon J. Coles and
• Michael B. Hursthouse

Beilstein J. Org. Chem. 2010, 6, 1002–1014, doi:10.3762/bjoc.6.113

• as precursors to highly electroactive polythiophenes [27][28]. We were interested in the self-assembly of compound 28 in the solid state to assess whether or not this material would be suitable as a semiconductor in OFETs [29]. Single crystals of compound 28 were grown from a dichloromethane/hexane

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

• ; gel-sol transition; rheology; viscosity; Introduction During the last two decades, research efforts have increased enormously to understand the range of structures and processes of self-assembly of ‘small’ molecules such as low-molecular-mass organogelators (LMOGs), which gelate large volume

• the basis for anisotropic self-assembly and recognition of the potential applications for such gels [4][5][6] – most can be reverted thermally to their solution (or sol) states – as models for several important biological aggregates (e.g., that are involved with neurodegenerative and other diseases

• ammonium carbamate from ODA, C18H37NHCO2− +H3NC18H37 (ODA-C), is held together much more strongly, by electrostatic forces, than uncharged latent LMOG molecules. Especially in liquids of low polarity, the electrostatic forces and ion pairing are very strong and they are the basis for the induced self

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

• bundles tens of micrometers long and more than 1 μm wide containing thin fibres (less than 300 nm). Upon gelation, it appears that self-assembly of the 3D fibres of these low molecular weight molecules results in the formation of fibrous networks. All these results appear to suggest the following gelation

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

• ; organogels; racemization; self-assembly; Introduction Gelation represents a macroscopic manifestation of self-assembled molecules. Impressive supramolecular architectures have been reported in which the self-assembled molecules immobilize solvent to produce a gel phase. Carefully designed self complementary

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

• characteristics were found to strongly influence both, gelator effectiveness and morphological characteristics of gel aggregates. Keywords: chiral; organogel; oxalamide; retro-peptide; self-assembly; Introduction Reversible processes of peptide, protein and nucleic acids self-assembly are of paramount

• importance in biotic systems and are central to vital biological functions. On the other hand, some pathological changes leading to diseases such as Alzheimer’s, Parkinson’s and prion diseases, type II diabetes, etc. are associated with anomalous self-assembly of smaller peptides into amyloid fibrils which

• hierarchical organisation was provided which determined the final morphological appearance of the aggregates [26]. It appears that gelation induced by aggregation of small abiotic or bio-inspired organic molecules represents an advantageous experimental system allowing in depth studies of the self-assembly as

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

• ; hydrogel; pyridinium; self-assembly; Introduction Gels are an outstanding group of soft materials lying at the interface of solid and liquid, and find numerous applications in various fields including tissue engineering, biosensors, food processing, cosmetics, photography, controlled drug delivery etc. [1

• 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

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

• temperature) vs [gelator] plots on some selected gels displayed a steady increase of Tgel with the increase in [gelator] which indicated that, in the present cases, self-assembly in the gel state was driven by strong supramolecular interactions such as hydrogen bonding. Application of the Schroeder-van Laar

• as the nucleation of gel fiber, kinetics of gel fiber growth, their self-assembly to form SAFINs and their interactions with the solvent molecules etc. are needed for a deeper understanding. Although we were successful in achieving an easy access to few chiral gels following this supramolecular

Organic gelators and hydrogelators

• Jean-Pierre Desvergne

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

• Jean-Pierre Desvergne Institut des Science Moléculaires, Université Bordeaux 1 - CNRS UMR 5255, 351 cours de la Libération, 33405 Talence Cedex, France 10.3762/bjoc.6.99 The design and control of molecular self-assembly is of great interest in the development of new molecular architectures with

• 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

Novel multi-responsive P2VP-block-PNIPAAm block copolymers via nitroxide-mediated radical polymerization

• Cathrin Corten,
• Katja Kretschmer and
• Dirk Kuckling

Beilstein J. Org. Chem. 2010, 6, 756–765, doi:10.3762/bjoc.6.89

• 2VP has been selected and the resulting polymer was used as a macroinitiator 2 (Scheme 1). Amphiphilic diblock copolymers undergo a self-assembly micellar process in solvents that are selective for one of the blocks [31]. By choosing selective conditions for each block, conventional micelles and so

Synthesis, electronic properties and self-assembly on Au{111} of thiolated (oligo)phenothiazines

• Adam W. Franz,
• Svetlana Stoycheva,
• Michael Himmelhaus and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2010, 6, No. 72, doi:10.3762/bjoc.6.72

• reveals a large difference of ΔE = 132 mV for the current peaks of the oxidation and the reduction wave. Presumably, the expected third and fourth oxidations coincide and give rise to a combined quasi-reversible peak. Self-assembly and ellipsometry SAMs on a Au{111}-coated silicon wafer substrate were