Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• ] with the energy cutoff of 35 (350) Ry for the expansion of wavefunction (charge density) described the electron-nuclear interaction. Using the 2 × 4 × 1 k-point mesh of Monkhorst–Pack [36], the Brillouin zone sampling was safely performed. Additional details of calculation conditions may be found in a

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• -aryl-N'-alkylindigo photoswitches 22b, 23c and 23d upon addition of Li+ cations. These studies revealed that the presence of the electron-withdrawing groups on the aryl moiety decreased the charge density on the carbonyl groups and weakened the interaction of the Z-isomers with Li+ that accounted for

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• @Ih-C80]2− = −1.62 V vs Fc+/Fc; C602− = −1.50 V vs Fc+/Fc)). The different reactivity of [M3N@Ih-C80]2− was explained by theoretical calculations. The charge density of the highest occupied molecular orbital (HOMO) was more highly localized on the fullerene cage for [Lu3N@Ih-C80]2−, whereas it was

• 3a was confirmed by the SC-XRD analysis, which showed that the addition site of addendum was indeed at the C10 position of La@C2v-C82 (Figure 5). The La@C2v-C82 anion can act as an electron donor and a nucleophile. To confirm the reaction mechanism, charge density and the p-orbital axis vector (POAV

• crystal has two independent units of 3a and three CS2 molecules as guest solvents. The difference between the two independent units is the direction of the tolyl group in the crystal (Supporting Information File 1, Figure S7). (a) Charge density of La@C2v-C82 anion as a function of its POAV values and (b

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• mentioned earlier, we recently reported the results of the theoretical investigation of different classes of NHCs and their NHC–Cu(I) complexes at the DFT level [21]. It was shown that in the NHC–Cu(I) complexes, the negative charge density is located mainly in the CuX region. The molecular electrostatic

• potential (MESP) maps of two such complexes are shown in Figure 6. It is noteworthy that the intensity of the red color indicative of the negative charge density is maximum around the Cu atom conferring a nucleophilic character on it. Thus, the reaction is initiated by the nucleophilic attack of the NHC–Cu

Mechanistic studies of the solvolysis of alkanesulfonyl and arenesulfonyl halides

• Malcolm J. D’Souza and
• Dennis N. Kevill

Beilstein J. Org. Chem. 2022, 18, 120–132, doi:10.3762/bjoc.18.13

• later in a full-length paper with contributions from their co-workers [27], realized that if the unimolecular reaction was occurring in aqueous dioxane solvents, then it should become even more dominant when the dioxane was replaced by 2,2,2-trifluoroethanol (TFE). Charge density distributions for TFE

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• counterions, multivalent ions exert a particularly strong influence on polyelectrolytes due to their high charge density [292]. Plamper et al. [293] as well as Zhang et al. [294] demonstrated that in the presence of the triply negatively charged hexacyanoferrate [Fe(CN)6]3−, polycationic poly

Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides

• Mathias B. Danielsen and
• Jesper Wengel

Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125

• are in general well tolerated RNase H substrates. Another important aspect is the overall net-charge and the charge density of the ON. As the sugar and nucleobase substitutions compensate for the anionic charge carried by the PO and PS-backbone, a more densely charged ON is created which can result in

DNA with zwitterionic and negatively charged phosphate modifications: Formation of DNA triplexes, duplexes and cell uptake studies

• Yongdong Su,
• Maitsetseg Bayarjargal,
• Tracy K. Hale and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2021, 17, 749–761, doi:10.3762/bjoc.17.65

• and 100 mM NaCl. The polyelectrolyte ion condensation theory can be used to explain how an N+ modification stabilises duplex formation: For natural DNA, the double-helical form has a higher charge density in comparison with the single-stranded form. During denaturation, a portion of the counterions

• bound to DNA are lost to the bulk solvent due to the reduction in charge density. For a DNA duplex with one zwitterionic strand, the charge density of duplex and single stranded states is balanced, and only a fraction of the counterions should be lost during denaturation. As a result, the thermal

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• displays the effective surface charge density as a possible determining parameter: As the ζ-potential represents a charge per radius (all as effective values at the shear plane of the particle diffusing in solution), the magnitude of the effective surface charge density is obtained by dividing the ζ

• -potential by RH. Previously we have reported that the effective surface charge density significantly controls the supramolecular particle size in electrostatic self-assembly [4][86][87]. (The effective surface charge density considers the effect of all particle charges at the shear plane.) For cycle I, the

• ζ-potential first increases, while the effective surface charge density decreases upon irradiation. Due to the photoacid changing from a di- to a trianionic molecule under irradiation and likely also due to the transformation of the Flavy molecule from the A to the B form, which leads to the

Supramolecular polymerization of sulfated dendritic peptide amphiphiles into multivalent L-selectin binders

• David Straßburger,
• Svenja Herziger,
• Katharina Huth,
• Moritz Urschbach,
• Rainer Haag and
• Pol Besenius

Beilstein J. Org. Chem. 2021, 17, 97–104, doi:10.3762/bjoc.17.10

• ] promotes the binding of ligands exhibiting a high local negative charge density, such as sulfotyrosinated P-selectin glycoprotein ligand-1 (PSGL-1) [23] or heparin [24]. A versatile synthetic ligand that takes advantage of binding to cationic target sites, is dendritic polyglycerol sulfate [25] (dPGS), due

Selected peptide-based fluorescent probes for biological applications

• Debabrata Maity

Beilstein J. Org. Chem. 2020, 16, 2971–2982, doi:10.3762/bjoc.16.247

• highly sulfated glycosaminoglycan with the highest negative charge density among known biomacromolecules. It is widely used as both a prophylactic and a therapeutic agent, especially as an anticoagulant in surgery [52][53]. But its overdose causes different adverse effects such as hemorrhages

Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes

• Thomas Schneider,
• Michael Keim,
• Bianca Seitz and
• Gerhard Maas

Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173

• characteristics of the C‒F bond [6][7] are the basis for the electronic and steric properties of the CF3 group, such as a strong electron-withdrawing (−I) effect, the accumulation of negative charge density in a relatively small volume and the low polarizability of the fluoro atoms. These and other substituent

Isolation and structure determination of a tetrameric sulfonyl dilithio methandiide in solution based on crystal structure analysis and ⁶Li/¹³C NMR spectroscopic data

• Jürgen Vollhardt,
• Hans Jörg Lindner and
• Hans-Joachim Gais

Beilstein J. Org. Chem. 2020, 16, 2057–2063, doi:10.3762/bjoc.16.172

• is no proof for the not existence of a C–Li-bonded species, because of the possibility of a fast C,Li exchange process, even at low temperatures. While the anion of 1 carries one lone pair at the carbon atom, the anion 2 bears two lone pairs. The higher negative charge density of the carbon atom of 2

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• photocatalytic degradation of basic organic dyes containing sulfonate groups, remazol black 5 (3, Figure 7) and procion red MX-5B (4, Figure 7), and showed a significant enhancement of 4 adsorption when the pH value was reduced to 3 (Figure 7) [98]. The authors stated that this reflected a higher positive charge

• density on the TiO2 surface at a lower pH value, which favours the adsorption of the dye via its negatively charged sulfonate groups. However, at a natural pH value, the increasing dye concentration gradually raises the pH value of the system and negatively charges the TiO2 surface, leading to an

Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos

• Sergii Afonin,
• Oleg Babii,
• Aline Reuter,
• Volker Middel,
• Masanari Takamiya,
• Uwe Strähle,
• Igor V. Komarov and
• Anne S. Ulrich

Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6

• the ring-closed and ring-opened isomers, we can presume that homodimerization may affect the way in which the peptides interact with their molecular targets, or it may compromise their long-term biostability. Likewise, an elongation of the β-sheet core and an increase in cationic charge density

• , in Figure 3A the peptides 19 and 20 are from series v (homodimers), compounds 16–18 have larger (extended) macrocycles and together with 5 possess a higher net charge and charge density than the rest of the peptides. For the most hydrophobic peptide 11 in the ring-open form, which deviates from the

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

• Enrique A. Del Vigo,
• Carlos A. Stortz and
• Carla Marino

Beilstein J. Org. Chem. 2019, 15, 2982–2989, doi:10.3762/bjoc.15.294

• functions describe better soft–soft interactions between nucleophiles and electrophiles [8][37][38]. The charge density was calculated for both methods using the Merz–Singh–Kollman scheme (MK) [39][40]. For the calculation of Fukui functions, besides the known computation of differences in atomic charges

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• literature there are still challenges to find selective iodide receptors due to its low basicity, large size and low charge density. There is an expectation that the combination of strong hydrogen-bonding sites and a large cavity could cause strong complexation with larger halide ions [55]. In 2016 a

Dynamic light scattering studies of the effects of salts on the diffusivity of cationic and anionic cavitands

• Anthony Wishard and
• Bruce C. Gibb

Beilstein J. Org. Chem. 2018, 14, 2212–2219, doi:10.3762/bjoc.14.195

• scattering of 1 was attributed to the high charge density of the host and the low ionic strength of the solution engendering significant Coulombic interactions between host molecules [24]. Titrating samples with the different salts led to much stronger light scattering and an apparent increase in the

• see no evidence of specific complexation here. More generally, despite the high charge density of 1, monovalent alkali metal ions cannot associate with it sufficiently to induce significant aggregation and a reverse Hofmeister effect. This was not, however, the case with divalent metal ions, which are

Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies

• Rakesh Puttreddy,
• Ngong Kodiah Beyeh,
• S. Maryamdokht Taimoory,
• Daniel Meister,
• John F. Trant and
• Kari Rissanen

Beilstein J. Org. Chem. 2018, 14, 1723–1733, doi:10.3762/bjoc.14.146

• , Supporting Information File 1), confirm the existence of bonds in this system. In other words, the bond critical point and bond path connecting two atoms are evidence for a real interaction rather than a simple spacial relationship. At the bond critical points, the electronic charge density [ρ(r)], and its

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• , indeed, possible dependence on pH might arise from the presence of the weakly basic 1,2,3-triazole rings of the linker units, which can supply an overall positive charge density to the polymer lattice upon protonation. A first set of experiments was devoted to p-nitroaniline derivatives 1–5. These

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• attributed to the highest positive charge density at the benzylic position, which is the favored process under kinetic conditions. During the attempted preparation of 4,5-benzotropone diaziridine 144, the synthesis of 7,7-dichloro-7H-benzo[7]annulene (135b) was also carried out from the reaction of 4,5

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• centimetre of electrocatalytic layer, Ageom (cm2) is the electrode geometric area and 0.424 refers to charge density expressed in mC per cm2 of Pd [29]. On the other hand, the roughness factor rf is also calculated according to Equation 2. Calculations of ESA and rf values were addressed for both Pd0.02/C/T

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• values on decreasing the pH is observed. These findings indicate that, on increasing the extension of the polyamine pendant bush, the outcome of favourable Coulomb effects decreases, probably due to a consequent decrease in the charge density of the bush itself. In all cases, non-monotonic RΘ trends are

Hydrolysis, polarity, and conformational impact of C-terminal partially fluorinated ethyl esters in peptide models

• Vladimir Kubyshkin and
• Nediljko Budisa

Beilstein J. Org. Chem. 2017, 13, 2442–2457, doi:10.3762/bjoc.13.241

• parent non-esterified peptides 9a and 10a. This is especially seen in the shortest trilysine sequence, where the esterification significantly increases the charge density, and thus the extended polyproline-II helix can be stabilized via the charge repulsion forces. Longer hexalysine sequences exhibited

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

• acids with a hydrocarbon chain length of 8–12 carbon atoms), where they can drive the formation of proton [75] or electron gradients [16]. In the case of photo-induced electron transport over membranes, the differentiated permeability of small anionic solutes with high charge density, such as potassium