Release of β-galactosidase from poloxamine/α-cyclodextrin hydrogels

• César A. Estévez,
• José Ramón Isasi,
• Eneko Larrañeta and
• Itziar Vélaz

Beilstein J. Org. Chem. 2014, 10, 3127–3135, doi:10.3762/bjoc.10.330

• are able to form host–guest complexes by the inclusion of hydrophobic molecules. Cyclodextrins also act as hosts in the formation of inclusion compounds with polymer chains through non-covalent interactions [10]. For instance, incorporation of 5% α-CD transforms dilute Tetronic solutions into gels

A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

• Debabrata Samanta,
• Anup Rana,
• Jan W. Bats and
• Michael Schmittel

Beilstein J. Org. Chem. 2014, 10, 2989–2996, doi:10.3762/bjoc.10.317

• with a 6-31G(d,p) basis set for hydrogen to include polarization on hydrogen and the 6-31G(d) basis set for the other main group elements using NWChem 6.3 [15]. During optimization, we utilized Grimme’s D3 dispersion [16] for a better description of non-covalent interactions like hydrogen bonding and π

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• shape, whereas the high polarizability (and permanent positive charge of N-5 alkylated derivatives) also plays an important role in aromatic and electrostatic interactions with polynucleotides. Moreover, non-covalent interactions with DNA and RNA can be reversibly controlled by a pH-induced positive

• allows the incorporation of considerably long substituents at 3,8- positions available for attachment to DNA and RNA and/or various additional non-covalent interactions with the polynucleotide backbone. The ethidium bromide incorporated as an artificial DNA base (18, Figure 9) at specific sites in duplex

Synthesis and biological evaluation of novel N-α-haloacylated homoserine lactones as quorum sensing modulators

• Michail Syrpas,
• Ewout Ruysbergh,
• Christian V. Stevens,
• Norbert De Kimpe and
• Sven Mangelinckx

Beilstein J. Org. Chem. 2014, 10, 2539–2549, doi:10.3762/bjoc.10.265

• with high structural deviation from the parent autoinducer [15]. In biological processes, covalent binding and non-covalent interactions are encountered in many protein-ligand interactions as well as in protein secondary structures and are of great significance. In the past years, it was shown that the

Towards the sequence-specific multivalent molecular recognition of cyclodextrin oligomers

• Michael Kurlemann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 2428–2440, doi:10.3762/bjoc.10.253

• -covalent interactions stable yet reversible systems are generated, which are responsive to external stimuli. These advantages have made synthetic multivalent systems interesting for a broad field of applications. In the case of medicinal applications multivalent molecules have been used as inhibitors of

• binding partner [1]. In recent years multivalency has been recognized to play a major role in almost all biological processes, e.g., the recognition of cells by other cells, bacteria or viruses, the adhesion of cells or signal transduction pathways [2]. By the combination of multiple, rather weak non

Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

• Marijana Radić Stojković,
• Marko Škugor,
• Łukasz Dudek,
• Jarosław Grolik,
• Julita Eilmes and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2175–2185, doi:10.3762/bjoc.10.225

• /RNA intercalation, minor or major groove binding, and external electrostatic binding [1]. However, non-covalent interactions involving small molecules (Mw < 600) can only rely on a small number of interacting groups, while the steric parameters of DNA/RNA binding sites are also quite limited

Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

• Simon Rondeau-Gagné,
• Jules Roméo Néabo,
• Maxime Daigle,
• Katy Cantin and
• Jean-François Morin

Beilstein J. Org. Chem. 2014, 10, 1613–1619, doi:10.3762/bjoc.10.167

• ; phenylacetylene macrocycles; polydiacetylenes; topochemical polymerization; Introduction The self-assembly of molecular building blocks is an increasingly popular method for the preparation of new semiconducting materials. Rational design of building blocks and their assembly using non-covalent interactions can

Substitution effect and effect of axle’s flexibility at (pseudo-)rotaxanes

• Friedrich Malberg,
• Jan Gerit Brandenburg,
• Werner Reckien,
• Oldamur Hollóczki,
• Stefan Grimme and
• Barbara Kirchner

Beilstein J. Org. Chem. 2014, 10, 1299–1307, doi:10.3762/bjoc.10.131

• non-covalent interactions between the axle and the wheel. Therefore, the understanding of these (mostly) attractive forces is crucial for the development of the field. Also, by understanding how one can modify or even tune the axle–wheel interplay, rotaxanes for different purposes can be designed

• enhancing the applicability of such materials. This study aims to understand rotaxanes with respect to its non-covalent interactions on the molecular level and to contribute to a more rational design of new molecular machines. Therefore, we investigated the energetics by substitution the rotaxanes with

• of non-covalent interactions. The distances R1, R2, and R3 are significantly smaller in the crystal compared to the gas phase structure. The torsion angles φ1 and φ2 describe the relative tilting between the flexible phenyl rings, which differs by more than 10° between crystal and gas phase. All

Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect

• Josué M. Silla,
• Claudimar J. Duarte,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2014, 10, 877–882, doi:10.3762/bjoc.10.84

• bond. Likewise, the 'quantum' nature of this hydrogen bond (the nF→σ*NH interaction) is not detected by NBO analysis. However, the new non-covalent interaction (NCI) approach, which is based on the electron density and its derivatives, enables the identification of non-covalent interactions by means of

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

• Sebastian Reinelt,
• Daniel Steinke and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 680–691, doi:10.3762/bjoc.10.61

• defined by J. M. Lehn in the 1970`s as “chemistry of the intermolecular bond” [1][2]. However, its origin goes back to Fisher`s “lock and key” model and also to Watson and Cricks description of the role of H-bonds in DNA double helical structures. Both examples represent the importance of non-covalent

• interactions in living systems [3][4]. Since then, the field of self-assembly through molecular recognition has attracted much attention also in the design of smart materials. In this context, cyclodextrins (CD) are of interest as ring shaped host molecules, e.g., for the design of stimuli-responsive hydrogels

Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials

• Valeria C. Edelsztein,
• Andrea S. Mac Cormack,
• Matías Ciarlantini and
• Pablo H. Di Chenna

Beilstein J. Org. Chem. 2013, 9, 1826–1836, doi:10.3762/bjoc.9.213

• , electrochemistry, light-harvesting materials and so on [1][2][3][4][5][6]. These small molecules self-assemble into regular supramolecular structures through non covalent interactions such as ion–ion, dipole–dipole, hydrogen bonding, π–π stacking, van der Waals, host–guest, and ion coordination, and in so doing

Computational study of the rate constants and free energies of intramolecular radical addition to substituted anilines

• Andreas Gansäuer,
• Meriam Seddiqzai,
• Tobias Dahmen,
• Rebecca Sure and
• Stefan Grimme

Beilstein J. Org. Chem. 2013, 9, 1620–1629, doi:10.3762/bjoc.9.185

• -pair wise potential is added to a standard DFT result [26]. A thorough energy benchmark study of various density functionals for general main group thermochemistry, kinetics and non-covalent interactions (GMTKN30 benchmark set) [27] showed that Zhao and Truhlar’s PW6B95 functional [28] in combination

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

• -assembled structures form mainly due to weak non-covalent interactions such as hydrogen-bonding, van der Waals forces, π–π interactions, charge-transfer interactions etc. in organogels, whereas, in aqueous gels, the major driving force for aggregation is hydrophobic interaction [2]. A number of

Supramolecular FRET photocyclodimerization of anthracenecarboxylate with naphthalene-capped γ-cyclodextrin

• Qian Wang,
• Cheng Yang,
• Gaku Fukuhara,
• Tadashi Mori,
• Yu Liu and
• Yoshihisa Inoue

Beilstein J. Org. Chem. 2011, 7, 290–297, doi:10.3762/bjoc.7.38

• non-covalent interactions in the ground state [4][5][6][7][8][9][10][11]. The geometrical and functional complementarity and the subsequent induced fit between chiral host and guest substrate should play a crucial role in determining the stereochemical fate of chiral photoreaction, and therefore the

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

• 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

Hoveyda–Grubbs type metathesis catalyst immobilized on mesoporous molecular sieves MCM-41 and SBA-15

• Hynek Balcar,
• Tushar Shinde,
• Naděžda Žilková and
• Zdeněk Bastl

Beilstein J. Org. Chem. 2011, 7, 22–28, doi:10.3762/bjoc.7.4

• that 3 was attached to the sieve surface by non-covalent interactions. Approximately 76% of the Ru content could be recovered from the sieve as 3 (as shown by NMR) by washing with THF at room temperature (indicating physical adsorption of 3 on the sieve). The residual Ru species on the sieve exhibited

• magnitude lower ε, not visible in Figure 6) in the spectrum of 3 reflect the d–d transition of the Ru(II) atoms [24]. Supported catalyst 3/SBA-15 exhibits the same spectrum suggesting no changes in the coordination sphere of Ru atoms occurred during immobilization of 3 on the sieve. Assuming non-covalent

• interactions between the Ru species and the support surface, we attempted to wash out the Ru species from 3/SBA-15 with THF-d8 and characterise the eluate by NMR spectroscopy. About 100 mg of 3/SBA-15 was mixed with 1.5 mL of THF-d8 and stirred for 2 h at room temperature. The dark green supernatant was then

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

• for a small set of solvents, its gelling ability is not universal [3][4][5][6][7][8][9][10][11]. This lack of generality doubtless arises as there is generally no single unifying mechanism for gelation, which invariably involves a range of physical (non-covalent) interactions, such as hydrogen bonding

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

• ; 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

• interest in the recent past due to their potential applications as active components in a variety of organic electronic devices [2]. Organogels are a special class of self-assembled materials in which small building blocks generate fibrous structures due to intermolecular non-covalent interactions, and

Chain stopper engineering for hydrogen bonded supramolecular polymers

• Thomas Pinault,
• Bruno Andrioletti and
• Laurent Bouteiller

Beilstein J. Org. Chem. 2010, 6, 869–875, doi:10.3762/bjoc.6.102

• Cedex, France 10.3762/bjoc.6.102 Abstract Supramolecular polymers are linear chains of low molar mass monomers held together by reversible and directional non-covalent interactions, which can form gels or highly viscous solutions if the self-assembled chains are sufficiently long and rigid. The

• held together by reversible and highly directional non-covalent interactions [1][2][3]. Because of their macromolecular architecture, they can display polymer-like rheological properties, and they can, in particular, form gels if the self-assembled chains are sufficiently long and rigid [4][5][6][7][8

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

• hydrophobic interactions is mandatory for any gelation process. Non-covalent interactions such as hydrogen bonding, ionic interactions, π–π stacking or van der Waals forces play a pivotal role in self-assembled gelation [12]. Tuning the structure of gelator molecules leads to a better understanding of the

• factors for the gelation process were found to be non-covalent interactions such as π–π stacking and intermolecular hydrogen bonding. These cationic amphiphilic molecules exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria and were found to be viable towards mammalian

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

• can be of two kinds – chemical or polymeric and physical or supramolecular. While covalent bonds are responsible for the formation of 3-D networks in chemical gels, various non-covalent interactions such as hydrogen bonding, π-π stacking, hydrophobic, van der Waals forces etc. are required to form gel

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

• and electrostatic interactions, coordination, and charge transfer. Additional non-covalent interactions lead to physical entanglement of the fibres, which creates a 3D network, the fluid being trapped in the nanoscale interstices. A very large quantity of solvent can be imprisoned in the

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

• exhibit molecular complementarity [18]. Today studies of non-covalent interactions, mainly by artificial model structures and receptors, have led to a far better understanding of many biological processes. Moreover, they are often the inspiration for supramolecular research, including self-assembly

• are used to enhance further the binding and selectivity with a binding mechanism that can be understood on the combined efforts of several non-covalent interactions such as hydrogen bonding, electrostatic interactions, hydrophobic interactions [20][21][22], cation–π interactions, π–π staking

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

• -ClPhNH3H2PO4 (8), 3-IPyBnCl (9), 3-IPyHCl (10) and 3-IPyH-5NIPA (3-iodopyridinium 5-nitroisophthalate, 13), where hydrogen or/and halogen bonding represents the most relevant non-covalent interactions, has been prepared and characterized by single crystal X-ray diffraction. This series was further complemented

• (Lewis base, nucleophilic) [20]. According to this definition, halogen bonding covers a vast family of non-covalent interactions, and a very wide range of interaction energies [20]. Concurrently with the development of practical applications and experimental studies on halogen bonding systems

• chemistry and crystal engineering is to identify the hierarchies of non-covalent interactions in order to develop efficient synthetic strategies for attaining advanced supramolecular systems [1]. The structure of a supramolecular assembly in crystalline solids generally results from the balance of all

Thematic series on supramolecular chemistry

• Christoph A. Schalley

Beilstein J. Org. Chem. 2009, 5, No. 76, doi:10.3762/bjoc.5.76

• recognition.” [1] As the above citation from a paper by Julius Rebek and his coworkers indicates, supramolecular chemistry at its beginning gave new impetus to physical organic chemistry, which at that time had got trapped in ever more detailed kinetic studies. Early on, the nature of non-covalent

• interactions was of great interest. The first synthetic host-guest complexes were studied with respect to their components’ ability to bind selectively to each other through weak interactions. Mostly cations were used as the guests, because they provided rather strong binding interactions due to their charge