Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• electrode surface was lower than that of 1 because the relatively large hydrodynamic radius of the aggregates decreased the number of electrode-accessible molecules. This increase in the hydrodynamic radius resulted in a decrease in the oxidation current. In the present study, HFIP (pKa = 9.30 in H2O) [15

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

• low viscosity, high density of polymer segments and functional groups as well as a smaller hydrodynamic radius and larger diffusion coefficient compared to linear polymer chains in solution. Amphiphilic AB-type copolymers spontaneously form micelle structures above a critical concentration by self

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

• visible, that is, one predominant assembly size. The size differs depending on the cycle and cycle step, lying between a hydrodynamic radius of RH = 142 nm and RH = 332 nm; that is, significant size changes occur upon triggering. A second smaller peak that in some samples occurs at higher relaxation times

Supramolecular polymers with reversed viscosity/temperature profile for application in motor oils

• Jan-Erik Ostwaldt,
• Christoph Hirschhäuser,
• Stefan K. Maier,
• Carsten Schmuck and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2021, 17, 105–114, doi:10.3762/bjoc.17.11

• temperatures, e.g., caused by engine heat. Common VIIs are based on poly(methyl acrylate) (PMA) [1]. These systems are able to increase the viscosity at elevated temperatures by increasing their hydrodynamic radius [2]. This is based on the fact that PMAs occur as coiled polymer chains with lower hydrodynamic

• develop such novel VIIs, we envisaged the use of ditopic building blocks, which are able to reversibly form supramolecular polymers at higher temperatures. Supramolecular polymerization should increase the hydrodynamic radius and thus was expected to lead to increased viscosities [9]. There are different

• Figure 6 for compound 2 in toluene, see Supporting Information File 1, chapter 7 for compound 1 and other solvents). Here, an effect of the temperature on the hydrodynamic radius can be observed. We find two different peak areas, one with sizes of 10–40 nm and one with 100–700 nm. At 25 °C, the peak area

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

•  5). Additional proof of the mechanical bond was provided by 1H DOSY NMR showing the same diffusion for thread and macrocycle signals with a diffusion coefficient of −9.33 m2/s and a hydrodynamic radius of 8.7 Å (see Figure S4 in Supporting Information File 1). Electrochemistry The ferrocene

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

• Constantin Stuckhardt,
• Diederik Roke,
• Wojciech Danowski,
• Edwin Otten,
• Sander J. Wezenberg and
• Ben L. Feringa

Beilstein J. Org. Chem. 2019, 15, 2767–2773, doi:10.3762/bjoc.15.268

• formation of a new set of signals was observed. DOSY NMR confirmed the formation of an assembly with a hydrodynamic radius which was similar to that of the cage Pd2(stable Z-1)4. Precipitation of the metal centers in this assembly using tetrabutylammonium glutarate liberates the ligands and they were

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• hydrodynamic radius of 14.3 Å (Figure 6d). The theoretically predicted radius for a capsular complex is 12.8 Å, that is in a reasonable agreement with experimental data. For comparison, the diffusion coefficient for (R)-2 under the same conditions is 3.6 × 10−10 m2 s−1 (Figure 6e) that corresponds to a

• hydrodynamic radius of 11 Å. Similar to interactions of RSA 1 with bidentate amines (amino acid methyl esters), interactions with tetradenate amine (R)-2 lead to the diastereotopic splitting of the signals of the methylene bridges (CH2SO3−, f) and their substantial upfield shift (Δδ 0.25 ppm, Figure 6c). The

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

• Boltzmann constant, T is the temperature, η is the viscosity of the solution, and rH is the hydrodynamic radius. In all cases, at the initial 20 mM concentration of NaOH the light scattering induced by 1 was weak. This resulted in relatively flat autocorrelation functions generated from the measured

Kinetic analysis of mechanoradical formation during the mechanolysis of dextran and glycogen

• Naoki Doi,
• Yasushi Sasai,
• Yukinori Yamauchi,
• Tetsuo Adachi,
• Masayuki Kuzuya and
• Shin-ichi Kondo

Beilstein J. Org. Chem. 2017, 13, 1174–1183, doi:10.3762/bjoc.13.116

• -branched polysaccharide could be measured by dynamic light scattering (DLS), it is difficult to precisely detect a particle with a diameter of less than 10 nm with our experimental setup. The hydrodynamic radius (Rh) is utilized as an index of the spread of a polymer. It is well-known that the Rh of a

Aggregation behavior of amphiphilic cyclodextrins in a nonpolar solvent: evidence of large-scale structures by atomistic molecular dynamics simulations and solution studies

• Giuseppina Raffaini,
• Fabio Ganazzoli and
• Antonino Mazzaglia

Beilstein J. Org. Chem. 2016, 12, 73–80, doi:10.3762/bjoc.12.8

• with a hydrodynamic radius of the order of 80 nm and a relatively modest polydispersity, even though smaller nanometer-sized aggregates cannot be fully ruled out. Taken together, these simulation and experimental results indicate that amphiphilically modified cyclodextrins do also form large-scale

• ). Figure 7 shows the monomodal hydrodynamic radii distribution obtained by using CONTIN inversion algorithm and Mie scattering normalization. As a result of the cumulant analysis [12], DLS evidences the presence of aggregates with ≈80 nm hydrodynamic radius (RH) and a polydispersity index of 0.2

• scattering investigations show that, indeed also in a nonpolar solvent such as dichloromethane, these amphiphilic cyclodextrins give rise to quite well defined aggregates, or nanostructures, having a hydrodynamic radius of about 80 nm and a relatively modest polydispersity. This result obtained with a

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study

• Yulia I. Denisova,
• Maria L. Gringolts,
• Alexander S. Peregudov,
• Liya B. Krentsel,
• Ekaterina A. Litmanovich,
• Arkadiy D. Litmanovich,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2015, 11, 1796–1808, doi:10.3762/bjoc.11.195

• mixtures) polymer/polymer phase separation. We addressed this issue with the light scattering measurements on PCOE (Mn = 140000 g/mol, Ð = 1.9), PNB (Mn = 80000 g/mol, Ð = 2.8), and PCOE/PNB solutions in CHCl3. For both polymers, only one relaxation mode was observed. The mean hydrodynamic radius

• carry out metathesis reactions at a PCOE concentration higher than 0.03 g/mL. DLS experiments on the PCOE/PNB mixtures were conducted at the equal component concentrations taken to be 0.015 and 0.03 g/mL. Figure 2 compares the normalized hydrodynamic radius distributions in the separate components and

• macromolecules). In the more concentrated solution (Figure 2b) PCOE particles grow (see also Figure 1b), thereby increasing the mean hydrodynamic radius of the PCOE/PNB mixture to 25 nm. It is important that in the both cases the mixture displays a unimodal distribution indicating that no polymer/polymer

Quarternization of 3-azido-1-propyne oligomers obtained by copper(I)-catalyzed azide–alkyne cycloaddition polymerization

• Shun Nakano,
• Akihito Hashidzume and
• Takahiro Sato

Beilstein J. Org. Chem. 2015, 11, 1037–1042, doi:10.3762/bjoc.11.116

• . Keywords: 3-azido-1-propyne oligomer; CuAAC polymerization; hydrodynamic radius; methyl iodide; pulse-field-gradient spin-echo NMR; quarternization; Introduction The copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) efficiently yields 1,4-disubstituted-1,2,3-triazole from rather stable azides and

• are not considerably dissociated in DMSO-d6. From the D0 value, the hydrodynamic radius (RH) was estimated to be 0.95 nm using the Einstein–Stokes equation. Figure 3a illustrates an extended conformation of oligoAPMe of n = 11 built with a ChemBio3D software (version 13.0). Here all the methyl groups

• indicated that the methylation occurred on both the 2- and 3-positions in 1,2,3-triazole under the present conditions. The hydrodynamic radius RH of oligoAPMe of n = 11 and xq = 0.96 in DMSO-d6 dilute solutions was determined to be 0.95 nm by PGSE NMR to study the conformation of the quarternized oligomer

Tuning the size of a redox-active tetrathiafulvalene-based self-assembled ring

• Sébastien Bivaud,
• Sébastien Goeb,
• Vincent Croué,
• Magali Allain,
• Flavia Pop and
• Marc Sallé

Beilstein J. Org. Chem. 2015, 11, 966–971, doi:10.3762/bjoc.11.108

• case shifted downfield (Figure 2c), as expected from coordination to a metal center. The corresponding DOSY NMR shows only one alignment of signals and confirms the formation of one unique species diffusing in solution with a D value of 6.35 × 10−11 m²·s−1 (Figure 2e). An estimated hydrodynamic radius

Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

• Stephan Schmidt,
• Hanqing Wang,
• Daniel Pussak,
• Simone Mosca and
• Laura Hartmann

Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82

• : For example, in case of the PEG-MA the density of mannose was ≈200 µmol/g, which translates to ≈4 grafted mannose units per PEG chain (average MW 8000 kDa). Considering the hydrodynamic radius of a PEG 8000 chains of ≈10 nm [8] this would mean that the spacing of mannose units was on the order of 2 nm

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

• aqueous solution, the block copolymers form so called schizophrenic micelles. The hydrodynamic radius Rh of these micelles associated with pH values and temperature was analyzed by dynamic light scattering (DLS). Such kind of block copolymers has potential for many applications, such as controlled drug

• PNIPAAm block with respect to the P2VP block, micelles formed by a PNIPAAm core and by a P2VP outer shell showed larger hydrodynamic radius. The schizophrenic behavior of P2VP105-block-PNIPAAm332 is summarized in Figure 9. Conclusion Well-defined P2VP macroinitiators were prepared using NMRP. The kinetic

• ) with a laser at 633 nm, a constant angle of 173° and a temperature of 25 °C. The hydrodynamic radius (Rh) was calculated using the Stokes–Einstein relation. The polymeric solutions were prepared from double-destilled water or 0.02 M HCl (aq) solution with polymer concentration of 0.5 g/L. All solutions

Free radical homopolymerization of a vinylferrocene/cyclodextrin complex in water

• Helmut Ritter,
• Beate E. Mondrzik,
• Matthias Rehahn and
• Markus Gallei

Beilstein J. Org. Chem. 2010, 6, No. 60, doi:10.3762/bjoc.6.60

• . However, the complexed polymer 3 shows a significantly larger hydrodynamic radius of 164 nm (Figure 1). The complexed polyvinylferrocene 3 was thermally stable up to about 90 °C in water, as demonstrated by turbidity measurements. The complex between methyl-β-CD 2 and polyvinylferrocene 4 remains stable