Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• ; Figure S36 in Supporting Information File 1). The formation of spherical particles with narrow size distribution and an average diameter of ≈2 nm was confirmed by DLS and DOSY NMR measurements (Figure 3e and Figure S27 in Supporting Information File 1). Based on molecular modeling, these data suggested

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• validated by 1H-DOSY NMR experiments (Figure 3, and Supporting Information File 1, Figure S26) indicating that the macrocycle and the axle diffuse as a whole with a diffusion coefficient of 4.2 × 10−10 m2/s. Conclusion In summary, we introduced herein a new synthetic strategy of [2]rotaxanes that combined

• HRMS, most probably because of the lower efficiency of the [1 + 1] reaction combined with the smaller size of the macrocycle. The [2]rotaxane R2 obtained by intramolecular clipping was successfully isolated as unique compound and its structure was validated by HRMS, 1H,13C and 1H-DOSY NMR experiments

• rotaxane R1 (left) and R2 (right) [experimental (top) and calculated (bottom) isotopic patterns]; middle: comparative 1H NMR spectra of the aromatic region of rotaxane R2 with the macrocycle and with the axle (CD2Cl2, 400 MHz); bottom: fragment of 1H-DOSY NMR (MeCN-d3, 400 MHz) spectrum of compound R2

A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand

• Matthias Hardy,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220

• and shape, however, DOSY NMR experiments could nicely be used to prove that all of the detected signals correspond to species of similar size with a solvodynamic diameter of 33 Å (Figure 5) and do not belong to species of a different composition. Unfortunately, despite our greatest efforts, we did not

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

• be expected when the homochiral enantiomers of cage structure Pd2(stable Z-1)4 are the only optically active species in solution (Figure S1, Supporting Information File 1). Additionally, DOSY NMR spectroscopy revealed that the signals correspond to a single type of assembly in each case (see

• 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

• chemistry. In the present study we demonstrate that resorcin[4]arene sulfonic acid (RSA) interacts with chiral amines (amino acid derivatives and aminocavitands) to form inclusion complexes and capsules based on electrostatic interactions. The complexes were characterized by circular dichroism and DOSY NMR

An azobenzene container showing a definite folding – synthesis and structural investigation

• Abdulselam Adam,
• Saber Mehrparvar and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2019, 15, 1534–1544, doi:10.3762/bjoc.15.156

• . For example, neither for the switchable platform 5 nor for the foldable container 6 a significant change of the diffusion coefficients caused by the switching process could be detected in the DOSY spectra of the compounds. This can be explained as follows: The DOSY NMR experiment measures the average

• ) are marked. HPLC spectra (ReproSil Phenyl, 5 μm, 250 × 8 mm; methanol) of trans,trans-10 (blue), cis,trans-10 (green) and cis,cis-10 (red) 20 min after isolation by means of HPLC. CD spectra of trans,trans-10 (blue), cis,trans-10 (green), and cis,cis-10 (red) in methanol (c = 3.0 × 10−5 M). DOSY NMR

Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter

• Indrajit Paul,
• Debabrata Samanta,
• Sudhakar Gaikwad and
• Michael Schmittel

Beilstein J. Org. Chem. 2019, 15, 1371–1378, doi:10.3762/bjoc.15.137

• (Supporting Information File 1). The ESIMS exhibited a single peak at m/z = 1534.5 (Supporting Information File 1, Figure S19) representing 5 = [Cu4(1)2(2)2]4+, constituting strong evidence that 5 is the sole product of this particular reaction. This notion was further ascertained by the 1H DOSY NMR

• :1) afforded complex 6 = [Cu2(1)(2)(4)]2+ as the exclusive product at room temperature. A single diffusion coefficient in the 1H DOSY NMR (D = 4.40 × 10−10 m2s−1) as well as a single set of signals in the 1H NMR spectrum provided evidence of high purity. The experimental radius of 12.0 Å reflects the

Coordination-driven self-assembly of discrete Ru₆–Pt₆ prismatic cages

• Aderonke Ajibola Adeyemo and
• Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2018, 14, 2242–2249, doi:10.3762/bjoc.14.199

• heterometallic prismatic cages 3a and 3b obtained from the reaction of two arene–ruthenium(II) clips 1a and 1b and tritopic platinum(II) metalloligand 2 in methanol/chloroform mixture in 3:2 ratio (Scheme 1). Both cages were fully characterized by 1H, 31P, 195Pt, 1H,1H COSY, DOSY NMR, electrospray ionization

• same observation is recorded for the 195Pt NMR analyses of all the heterometallic cages (Supporting Information File 1, Figures S17 and S18). The DOSY NMR experiments also confirmed the formation of a single product in all the cages with the hydrodynamic radii (rH) of the heterometallic prismatic cages

• calculated from the Stokes–Einstein equation using the diffusion coefficients (D) obtained from the DOSY NMR experiments. The obtained values of D from the experiment are −9.631 log (m2 s−1) for 3a and −9.567 log (m2 s−1) for 3b, respectively. The calculated hydrodynamic radii (rH) of 3a and 3b are 15.57 Å

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• amperometric detection. More insights on this debate were obtained by means of DFT calculations only (see section 3.3). 3.3 Assignments by means of 2D-1H-DOSY NMR in tandem with DFT calculations at dendritic level Except for dendrimers 4 (dH 2.45 nm) and 5 (dH 2.48 nm) (Table 3), in the series of trimers 7–9

• the expected increase in the hydrodynamic diameters (dH) with respect to their G-1 monomeric precursor, D-N

  NH (1.98 nm), was negligible (1.90–2.04 nm). 2D-1H-DOSY NMR charts of G-2 dendrimers 7a (covalent) vs ionic 7b, 8 and 9 (Figure 5) displayed unique structures, with a partial dissociation of

• 7b, presumably due to the sterically induced imperfect accommodation of the three G-1 cationic dendrons D-N

  NH2+ around the smallest central tris-anion of the series, trimesic tris-carboxylate. In other words, the 2D-1H-DOSY NMR charts were consistent with the envisaged 3(D-N

  NH):1 (trimesic acid

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

• aqueous phosphate buffer (right, 50 mM buffer, pH 7.0) samples. Recorded at 298 K and 100 μM peptide. Conformational analysis of the peptides by 1H DOSY NMR (D2O, 298 K). The theoretical values were calculated according to Equation 5 assuming deuterium oxide viscosity and 298 K. Hydrolysis of the C

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• ) belong to the protons in the imidazolium ring. The chemical shifts at 0.8 ppm and 1.2 ppm belong to the alkyl chain of the CTA, while the remaining signals are attributed to the polymer. The DOSY NMR spectrum (Figure S3 in Supporting Information File 1) proves that there is only one polymeric species

Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

• Miriana Kfoury,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2016, 12, 29–42, doi:10.3762/bjoc.12.5

• : cyclodextrins; DOSY-NMR; formation constant; molecular modeling; solubility; Introduction Carvacrol (2-methyl-5-(1-methylethyl)phenol, 1) and thymol (5-methyl-2-(1-methylethyl)phenol, 2) are monoterpenic phenol isomers (Figure 1) produced by several aromatic plants (oregano, thyme, savory, marjoram, etc.) [1

• enhancement ratio (St/S0), complexation efficiency (CE), optimum molar ratio and increase in formulation bulk of each guest. 2D DOSY NMR spectra of (a) β-CD, carvacrol (1) and β-CD/carvacrol (1) inclusion complex and (b) β-CD, thymol (2) and β-CD/thymol (2) inclusion complex. Representation of chemical shifts

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

• -assembly M4L2. For clarity, H atoms and TfO− counteranions have been omitted. 1H NMR, downfield region (α and β signals correspond respectively to α and β pyridyl protons): (a) L1 (DMSO-d6), (b) M4L2 (CD3NO2), (c) M6L3 (DMSO-d6), (d) DOSY NMR of M4L2 (CD3NO2) and (e) DOSY NMR of M6L3 (DMSO-d6). X-ray

Functionalized branched EDOT-terthiophene copolymer films by electropolymerization and post-polymerization “click”-reactions

• Miriam Goll,
• Adrian Ruff,
• Erna Muks,
• Felix Goerigk,
• Beatrice Omiecienski,
• Ines Ruff,
• Rafael C. González-Cano,
• Juan T. Lopez Navarrete,
• M. Carmen Ruiz Delgado and
• Sabine Ludwigs

Beilstein J. Org. Chem. 2015, 11, 335–347, doi:10.3762/bjoc.11.39

• and EDOT as a straightforward approach to conducting polymer films with tailored HOMO levels and therefore band gap values by varying the monomer ratio during chemical (with FeCl3 as oxidant) and electrochemical polymerization [24]. Characterization of the chemically polymerized copolymers by 1H DOSY

• NMR and MALDI–TOF spectroscopy indicated that the EDOT and 3T units are covalently linked. While comparisons with these chemically synthesized polymers support our finding, a real proof of copolymer formation for the electropolymerized films was still missing in our previous publication. Here, we show

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• , were found to adopt closed conformations by intramolecular self-inclusion. On the other hand, association via intermolecular binding was also observed in aqueous solution, confirmed by DOSY NMR experiments. Despite self-inclusion, the β-CD cavities were capable of guest encapsulation, as shown by

Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

• Rainer Hovorka,
• Sophie Hytteballe,
• Torsten Piehler,
• Georg Meyer-Eppler,
• Filip Topić,
• Kari Rissanen,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 432–441, doi:10.3762/bjoc.10.40

• second bis(pyridine) ligand (S)-6 in a two-fold Suzuki reaction. Metal coordination After the successful synthesis we mixed solutions of ligands 3 and 6 and [(dppp)Pd(OTf)2] or [(dppp)Pt(OTf)2] and characterised the resulting complexes by 1H, 31P, 1H 2D-DOSY NMR, ESI-MS, and single crystal X-ray

• further confirmed by 2D 1H DOSY NMR spectra (see Supporting Information File 1) of the aggregates as well as of the free ligands. In all cases the relative size of the aggregates was a little more than twice as large as that of the respective concave template. (Please note, that we could only determine