Conformational impact of structural modifications in 2-fluorocyclohexanone

• Francisco A. Martins,
• Josué M. Silla and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2017, 13, 1781–1787, doi:10.3762/bjoc.13.172

• and σC–H2ax → π*C=S interactions are more stabilizing than σC–H2ax → π*C=C, but they are also accompanied by strong steric and electrostatic interactions (see the high values for both Lewis and non-Lewis terms when Y = O and S compared to CH2). When the X = S and NHeq groups take place, the equatorial

• < S, since the repulsion with the Feq substituent increases in this order. The hypothesis based on steric and electrostatic interactions is supported by the increase of the axial population from Y = CH2 to S, despite the better electron-acceptor ability of the π*C=S in comparison to π*C=O and π*C=C

• the electronic delocalization energies, as well as the Lewis (steric and electrostatic interactions) and non-Lewis (electron delocalization) contributions through the NOSTAR keyword. Chemical shifts and spin–spin coupling constant calculations were also performed at the ωB97X-D/6-311+g(d,p) level. All

Chemical systems, chemical contiguity and the emergence of life

• Terrence P. Kee and
• Pierre-Alain Monnard

Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155

• research groups have demonstrated their abilities to induce formation of evolved protocell systems. For instance, they have been shown to be capable of accumulating small molecules on their charged surfaces (electrostatic interactions) [49] or within pores and brines by thermophoresis and convection

2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization

• Julia Kinzel,
• Daniel F. Sauer,
• Marco Bocola,
• Marcus Arlt,
• Tayebeh Mirzaei Garakani,
• Andreas Thiel,
• Klaus Beckerle,
• Tino Polen,
• Jun Okuda and
• Ulrich Schwaneberg

Beilstein J. Org. Chem. 2017, 13, 1498–1506, doi:10.3762/bjoc.13.148

• distributed MPD molecules as cosolvent [52][53][54][55][56]. The MD calculations (75 ns each) were performed using the AMBER99 force field for the protein and GAFF for MPD cosolvent. The electrostatic interactions were calculated using a 8 Å cut-off and Particle Mesh Ewald [57] for long range electrostatics

Towards open-ended evolution in self-replicating molecular systems

• Herman Duim and
• Sijbren Otto

Beilstein J. Org. Chem. 2017, 13, 1189–1203, doi:10.3762/bjoc.13.118

• enhanced by electrostatic interactions between amino acids residing on the c and g positions of the α-helices. Ghadiri et al. showed that such coiled-coil peptides are capable of self-replication [35]. As depicted in Figure 7, helical polypeptides can act as a template for shorter peptide fragments by

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• pHs, further supported the proposed electrostatic interactions between DOX and the CDs. Further studies showed initial efficacy of the DOX–CD adduct as a beneficial drug-delivery system, even in animal models. On the other hand, Zhao et al. described an alternative synthesis for N/P-doped CDs

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• receptors for anions have been developed based on various modes of interactions such as hydrogen bond and electrostatic interactions which rely on directionality and distance-dependent nature, respectively. Hydrogen bond formation is further tuned by the acidity of protons by virtue of the presence of

Cross-linked cyclodextrin-based material for treatment of metals and organic substances present in industrial discharge waters

• Élise Euvrard,
• Nadia Morin-Crini,
• Coline Druart,
• Justine Bugnet,
• Bernard Martel,
• Cesare Cosentino,
• Virginie Moutarlier and
• Grégorio Crini

Beilstein J. Org. Chem. 2016, 12, 1826–1838, doi:10.3762/bjoc.12.172

• groups and CD cavities, the adsorption mechanism involves four main interactions: ion exchange, electrostatic interactions and precipitation for metal removal, and inclusion complexes for organics removal. In industrial discharge waters, competition effects appeared, especially because of the presence of

• material was initially activated by NaHCO3. Discussion To explain the adsorption performance of polyBTCA-CD, a chemisorption mechanism involving several interactions can occur including ion exchange, electrostatic interactions, inclusion complexation and/or precipitation [3][12][13][14][15][16]. The

• sodium bicarbonate was necessary to enhance metal retention, as also reported by Ducoroy et al. [17], allowing for a removal efficiency for metals higher than 99% for Co2+, Ni2+ and Zn2+, through both electrostatic interactions and ion exchange. Indeed, during the process of polymer synthesis, the cross

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• very close to that of IMP or to the previously characterized inhibitor, UA1776. This may be explained by the presence of a phosphonate chain in all compounds which binds to the protein by electrostatic interactions through the magnesium ion and thus largely contributing to the final score. As the

Stimuli-responsive HBPS-g-PDMAEMA and its application as nanocarrier in loading hydrophobic molecules

• Yongsheng Chen,
• Li Wang,
• Haojie Yu,
• Zain-Ul-Abdin,
• Ruoli Sun,
• Guanghui Jing,
• Rongbai Tong and
• Zheng Deng

Beilstein J. Org. Chem. 2016, 12, 939–949, doi:10.3762/bjoc.12.92

• aggregation behavior of HBPS-g-PDMAEMA The electrostatic interaction is a major factor to influence the behavior of PDMAEMA in aqueous solution. So in this work, the influence of ionic strength, which affects the electrostatic interactions, was studied. In this case, pH was not adjusted and deionized water

• aqueous solution with relatively low concentrations of NaCl, and there was no maximum point. This is because higher concentrations of NaCl lowered the repulsive electrostatic interactions between PDMAEMA chains. So, higher concentrations of NaCl led to smaller aggregation sizes. The change of size was

Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins – new media for capillary separation techniques

• Gabor Benkovics,
• Ondrej Hodek,
• Martina Havlikova,
• Zuzana Bosakova,
• Pavel Coufal,
• Milo Malanga,
• Eva Fenyvesi,
• Andras Darcsi,
• Szabolcs Beni and
• Jindrich Jindrich

Beilstein J. Org. Chem. 2016, 12, 97–109, doi:10.3762/bjoc.12.11

• held together by non-covalent interactions, such as electrostatic interactions, coordination bonds, hydrogen bonds, hydrophobic interactions and host–guest interactions [1]. Their formation is spontaneous and reversible by self-assembly of the monomer units. Because of this special non-covalent

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• associative forces including hydrogen bonding, coordinate bonding, electrostatic interactions and hydrophobic interactions is ubiquitous in nature. This is exemplified by the use of DNA and RNA complementarity [1][2] and polypeptide helix formation [3][4] to produce three-dimensional structures and materials

Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

• Waratchada Sangpheak,
• Jintawee Kicuntod,
• Roswitha Schuster,
• Thanyada Rungrotmongkol,
• Peter Wolschann,
• Nawee Kungwan,
• Helmut Viernstein,
• Monika Mueller and
• Piamsook Pongsawasdi

Beilstein J. Org. Chem. 2015, 11, 2763–2773, doi:10.3762/bjoc.11.297

• was truncated within a 12 Å cutoff distance. The particle-mesh of Ewald’s method [64] was used for adequate treatment of the long-range electrostatic interactions with 12 Å cutoff. All bond lengths involving hydrogen atoms were constrained by SHAKE [32]. The coordinates were recorded every 500 steps

Size-controlled and redox-responsive supramolecular nanoparticles

• Raquel Mejia-Ariza,
• Gavin A. Kronig and
• Jurriaan Huskens

Beilstein J. Org. Chem. 2015, 11, 2388–2399, doi:10.3762/bjoc.11.260

• role in controlling the aggregate growth. The attractive supramolecular and repulsive electrostatic interactions constitute a balance of forces in this system at low ionic strengths. At higher ionic strengths, the increased charge screening led to a loss of electrostatic repulsion and therefore to

• . Davis et al. showed the formation of SNPs using attractive electrostatic interactions between positively charged β-cyclodextrin (CD)-containing polymers and negatively charged siRNA at the core [8]. Neutral adamantyl-grafted poly(ethylene glycol) (Ad-PEG) was incorporated at the surface to stabilize

• repulsive electrostatic interactions using a multicomponent system based on a linear, negatively charged polymer. The force balance used in the latter approach was only observed with negatively charged polymers at low ionic strengths, and it is not known whether this balance occurs also for positively

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• on a modified linear response to treat electrostatic interactions with an empirical term treating the dispersion interactions. In this work, the ΔGsolv was considered as polar and non-polar solvation terms. The polar solvation term is evaluated from the Poisson–Boltzmann (PB) solvation method which

• ) was a preferable arrangement. On the other hand, in complex I, the secondary rim is wide enough to support two functional groups of the C-ring. Even though α-MGS has three hydroxy groups, no hydrogen bonding between guest and host molecules was detected. Thus, electrostatic interactions may not be the

• higher than for electrostatic interactions (ΔEele). Through summation of the solvation free energy (ΔGsolv) and the entropy term (TΔS), the predicted binding free energies (ΔGbind) of the inclusion complexes I and II are similar with values of –8.86 ± 3.25 and –9.06 ± 2.87 kcal/mol, respectively. Thus

Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp²)–H bond arylations

• Fatiha Abdelmalek,
• Fazia Derridj,
• Safia Djebbar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2015, 11, 2012–2020, doi:10.3762/bjoc.11.218

• dramatically influence both chemical properties and reactivities owing to its electronegativity, size, lipophilicity, and electrostatic interactions. For example, introduction of fluorine into natural products can result in beneficial biological properties [6]. On the other hand, fluorinated π-conjugated

Surprisingly facile CO₂ insertion into cobalt alkoxide bonds: A theoretical investigation

• Willem K. Offermans,
• Claudia Bizzarri,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 1340–1351, doi:10.3762/bjoc.11.144

• )-phenoxide to form zinc(II)–phenylcarbonate [47]. The CO2 insertion was found to take place via electrostatic interactions between the electron lone pairs of the zinc-bonded oxygen and the carbon of CO2, forming an intermediate that finally produces a stable insertion product. Current research: CO2 Insertion

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• second oxidation step (Eapp0ox2) leading to fully oxidized TTF units is in accordance with independent TTF2+ states subject to repulsive electrostatic interactions. Such splitting phenomenon of the first oxidation wave has been previously reported by Azov et al. for TTF-containing molecular tweezers

Impact of multivalent charge presentation on peptide–nanoparticle aggregation

• Daniel Schöne,
• Boris Schade,
• Christoph Böttcher and
• Beate Koksch

Beilstein J. Org. Chem. 2015, 11, 792–803, doi:10.3762/bjoc.11.89

• Strategies to achieve controlled nanoparticle aggregation have gained much interest, due to the versatility of such systems and their applications in materials science and medicine. In this article we demonstrate that coiled-coil peptide-induced aggregation based on electrostatic interactions is highly

• of assemblies is most likely achieved by hydrogen bonds or other common receptor–binding interactions [28]. Although it is known that nanoparticles can be organised by binding to membranes by means of electrostatic interactions between the charged head group of the lipid and the oppositely charged

• nanoparticle [29], only limited effort has been put forth to use peptides or proteins to organize nanoparticles by electrostatic interactions [30][31]. As the overall net charge of a peptide is pH dependent, this can be a powerful tool for the controlled and reversible assembly of nanoparticles. Recently we

Discrete multiporphyrin pseudorotaxane assemblies from di- and tetravalent porphyrin building blocks

• Mirko Lohse,
• Larissa K. S. von Krbek,
• Sebastian Radunz,
• Suresh Moorthy,
• Christoph A. Schalley and
• Stefan Hecht

Beilstein J. Org. Chem. 2015, 11, 748–762, doi:10.3762/bjoc.11.85

• (Soret band) and less intense absorption bands between 500 and 600 nm (Q-bands). However, A4 shows rather strong aggregation even in the µM concentration regime likely caused by electrostatic interactions mediated by the closely associated BArF counter-ions that are expected to be significant as rather

Trifluoromethyl-substituted tetrathiafulvalenes

• Olivier Jeannin,
• Frédéric Barrière and
• Marc Fourmigué

Beilstein J. Org. Chem. 2015, 11, 647–658, doi:10.3762/bjoc.11.73

• strongest electrostatic interactions between the most electron-rich and electron-poor regions of both partners. In that respect, it appears here that the TCNQ acceptor essentially overlaps with the dithiole ring bearing the dithioethylene substituent, a likely consequence of the electron-withdrawing effect

Formulation development, stability and anticancer efficacy of core-shell cyclodextrin nanocapsules for oral chemotherapy with camptothecin

• Hale Ünal,
• Naile Öztürk and
• Erem Bilensoy

Beilstein J. Org. Chem. 2015, 11, 204–212, doi:10.3762/bjoc.11.22

• to higher cellular adhesion and increasing residence time at the cell surface provided by CS molecules. This finding suggests that with chitosan-coated cationic NCs, electrostatic interactions between positively charged CS amino groups and the negatively charged cell membrane occurred. Therefore, the

Properties of cationic monosubstituted tetraalkylammonium cyclodextrin derivatives – their stability, complexation ability in solution or when deposited on solid anionic surface

• Martin Popr,
• Sergey K. Filippov,
• Nikolai Matushkin,
• Juraj Dian and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2015, 11, 192–199, doi:10.3762/bjoc.11.20

• surface of polymeric Nafion® 117 membrane via electrostatic interactions. Deposition kinetics and coverage of the surface were determined by ELSD. Finally, the ability of the CD derivatives bound to the solid surface to encapsulate aromatic compounds from aqueous solution was measured by UV–vis

• capillary zone electrophoresis [8][9][10][11][12] and also as catalysts of chemical reactions [13][14][15]. The main goal of our research is to explore the possibility of binding of the monosubstituted cationic CD derivatives to an anionic surface by simple electrostatic interactions. Such an assembly could

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• the active conformation of the enzyme molecule by destabilizing electrostatic interactions, and even strip off the essential water layer (water of hydration) leading to loss of the biocatalytic activity. In turn, more lipophilic organic solvents positively interact with the enzyme protein enhancing

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

Binding mode and free energy prediction of fisetin/β-cyclodextrin inclusion complexes

• Bodee Nutho,
• Wasinee Khuntawee,
• Chompoonut Rungnim,
• Piamsook Pongsawasdi,
• Peter Wolschann,
• Alfred Karpfen,
• Nawee Kungwan and
• Thanyada Rungrotmongkol

Beilstein J. Org. Chem. 2014, 10, 2789–2799, doi:10.3762/bjoc.10.296

• the SANDER module in accordance with our previous studies [40][41][42]. The particle-mesh of Ewald’s method [43] was used for the treatment of the long-range electrostatic interactions with 12 Å cutoff distance. In order to constrain all bonds with hydrogen atoms, the SHAKE algorithm [44] was applied