Spatial arrangements of cyclodextrin host–guest complexes in solution studied by ¹³C NMR and molecular modelling

• Konstantin Lebedinskiy,
• Ivan Barvík,
• Zdeněk Tošner,
• Ivana Císařová,
• Jindřich Jindřich and
• Radim Hrdina

Beilstein J. Org. Chem. 2024, 20, 331–335, doi:10.3762/bjoc.20.33

• dispersion forces and hydrogen bonding between the cyclodextrin (CD) unit and the guest molecule. Determination of the ee of chiral guests was achieved by observing the splitting of 1H NMR signals of the achiral host upon formation of diastereomeric inclusion complexes [18][19]. Shifting the H-3 and H-5

Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• Computational methods). This significant amount of energy, which could be overestimated, comes from the π–π interactions between the C60 surface and the CNT wall and is modelled in a first approximation using Grimme’s corrections to the dispersion energy [16]. This interaction energy is comparable to those in

• . Grimme3 BJ-DAMP dispersion corrections have also been included in all calculations [24]. Stationary points were fully characterized by computing the Hessian matrix. Car–Parrinello molecular dynamics (CPMD) simulations were performed by means of the CPMD program [25][26]. The description of the electronic

• ) [27]. The PBE functional was selected as the density functional. Dispersion corrections were also considered in the calculations. We used a fictitious electron mass of 800 a.u. The simulations were carried out using periodic boundary conditions in a tetragonal cell (side length of 11 Å and height of

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• containing 40 mL of methanol and 20 mL of an H2PtCl6·6H2O solution (0.03 mM) was added to the dispersion. The resulting suspension was stirred under N2 atmosphere for 45 min followed by irradiation over 2 h with six 365 nm LEDs (with a total photon flux of 4.7 µmol s−1) mounted on 2 heat sinks (see

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• 305-8571, Japan 10.3762/bjoc.20.7 Abstract We successfully prepared a surfactant-assisted carbon nanotube (CNT) liquid crystal (LC) dispersion with double-walled CNTs (DWCNTs) having a high aspect ratio (≈1378). Compared to dispersions of single-walled CNTs (SWCNTs) with lower aspect ratio, the

• transition concentrations from isotropic phase to biphasic state, and from biphasic state to nematic phase are lowered, which is consistent with the predictions of the Onsager theory. An aligned DWCNT film was prepared from the DWCNT dispersion by a simple bar-coating method. Regardless of the higher aspect

• . Keywords: aqueous dispersion; bar-coating; carbon nanotube; coffee-ring effect; liquid crystal; Introduction Carbon nanotubes (CNTs) are cylindrical carbon structures with high electrical conductivity and tensile strength in the direction of the tube, anticipated as durable and highly conductive fibers

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• , compound 7 is characterized by electron transport. The recorded current transients for electrons in vacuum-deposited films of compound 7 show moderate dispersion (Figure 8a). In contrast, the hole transport was not detected, apparently because of the low mobility of holes being out of the detectable range

• –7.79 (m, 2H), 7.63–7.50 (m, 2H); GC–MS: 442 [M]+. 2,6-Bis(3,6-di-tert-butylcarbazol-9-yl)-4-(4-bromophenyl)pyridine-3,5-dicarbonitrile (4). Sodium hydride (60% oil dispersion, 180 mg, 5.36 mmol, 3.2 equiv) was added to THF (15 mL) under Ar atmosphere. Then, 3,6-di-tert-butyl-9H-carbazole (1.40 g, 5.3

• as host and compounds 6–9 (10 wt %). Non-normalized (a) and normalized (b) PL spectra and PL decay curves (c) of the film of a 10 wt % molecular dispersion of compound 9 in mCP recorded at the indicated different temperatures. PL and phosphorescence spectra of the same sample recorded at 77 K. (d

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• , using the Orca 5.0.3 [40] software package within B3LYP/Def2-TZVP(-f) level of theory [41][42][43][44][45]. Dispersion effects were included using Grimme’s D3 correction with Becke-Johnson (BJ) damping [45][46]. The evaluation of the four-center integrals was accelerated with the RIJCOSX algorithm [47

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• , finally, the structure with the lowest energy, with the functional PBE0-D4/mTZVPP/CPCM. The Hartree–Fock plus London dispersion (HFLD) method was used for the study of non-covalent interactions (NCI). The calculations lead to the conclusion that a reduction in electrostatic interactions and an increase in

• exchange and dispersion interactions in CHCl3 in relation to DMSO are the driving forces behind the placement of sec-amine molecules into the R[4]A cavity and the formation of “in” type complexes. Keywords: complexes; DFT calculations; hydrogen bond; resorcin[4]arene; supramolecular chemistry

• of non-covalent interactions within various types of supramolecular complexes [17]. One such method is HFLD [18], which can be considered a dispersion-corrected HF approach where the dispersion interaction between fragments is added at the DLPNO-CC level. The HFLD method demonstrates comparable

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• halogen bond is influenced by multiple factors including polarization, electrostatic attraction, charge transfer, dispersion and molecular orbital interactions [59][60][61][62][63]. The charge transfer nature (donation into the σ* orbital of the R–X bond) of the halogen bond leads to elongation and

• more complex theories as to why such adducts evolve differently. As previously stated, the strength of a halogen bond interaction is impacted by various factors (e.g., electrostatics, charge transfer abilities, dispersion), where the extent of their influence depends on both the halogen bond donor and

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• ). Single point energy calculations were performed using long-range corrected hybrid density functional ωB97X, which offer very good performance and have been recommended for general use in chemistry [27] with empirical dispersion correction D4 [28] (ωB97X-D4) and the triple-zeta def2-TZVPPD basis set [29

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• functional with D3 Grimme’s dispersion correction [42][43] and 6-311++G(d,p) basis set. All reported minima and transition state structures were confirmed by calculation and diagonalization of their Hessian matrices. The reported energies are Gibbs free energies calculated with the SMD method in N,N

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• -soluble bowl-shaped six-fold carboxylated tribenzotriquinacene derivative TBTQ-C6 via host–guest binding. The spherical nanoparticles formed by CS-TPE amphiphiles or TBTQ-C6/CS-TPE supra-amphiphiles disintegrated under alkaline stimulation at pH 10.4 and the dispersion of the aggregates after the collapse

• exposure to alkaline environmental stimuli at pH 10.4, and the assembly and disassembly processes were reversible (Scheme 1). The introduction of the TBTQ-C6 host significantly improved the dispersion of the aggregates formed after the collapse of the spherical nanoparticles under alkaline conditions. In

• at pH 10.4. Interestingly, when the host molecule TBTQ-C6 was added, the spherical nanoparticles showed significantly less sample build-up and improved dispersion after disintegration under alkaline conditions as compared to CS-TPE alone. The fluorescence intensity of both nanospheres was

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• S2 in Supporting Information File 1, p. S11). Product recovery was initiated when the system reached a steady state, based on the dispersion curves provided with the apparatus (see Supporting Information File 1, p. S13). This equipment is a medium pressure system that cannot withstand pressures

• initiated when the system reaches a steady state, based on the dispersion curves given by the apparatus. After reaching the steady state an aliquot of the product was taken for 1H NMR analysis using p-dinitrobenzene as an internal standard. 3-(2-(Triethoxysilyl)ethyl)furan-2-carbaldehyde (2a) The reaction

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• electrochemically induced oxidative modification of the amino acid side chain. Experimental and DFT studies showed that the additional tert-butyl group increases the dispersion interactions in the Ni coordination environment making the complexes more conformationally rigid and provides a higher level of

• give rise to additional dispersion interactions with the phenyl ring in the proline auxiliary, making the Schiff base complexes more conformationally rigid, thus increasing the stereochemical outcome of the functionalized amino acids as compared to the parent ligand L1. In the present paper, the new

• are presented in different colors: the hydrogen bonding are labeled in blue color of the reduced density gradient isosurface; green color corresponds to the dispersion interactions (van der Waals interactions, the π-stacking); red color represents steric clashes. The interplay of these through-space

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• dissolved in 1 mL of acetone to achieve an organic phase concentration of 0.1% (w/v). This organic phase was added drop-by-drop into 2 mL of the aqueous phase with magnetic stirring at room temperature for 30 min. The organic solvent was evaporated under vacuum at 45 °C to a final dispersion volume of 2 mL

• nanoparticle dispersion (3 mL) was then put in release medium (20 mL) that ensured external sink conditions. At predefined time intervals (0.5, 1, 2, 3, 5, 7, 10, and 24 h), 500 µL of sample were taken from the dialysis membrane and replaced with an equal volume of fresh release medium at the same temperature

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

• as a control) using M11-L optimization. Two fourth rung [90] functionals, M11 and MN12-SX [105][106], also failed to give any improvement (Table 4, entries 19 and 20), and these were also worse than the older fourth rung [90] functional M06-2X. Grimme’s D3 dispersion correction has been recommended

• corrected range-separated functional with dispersion correction [96], was also found to be highly accurate, and it was the most recently developed of the five representative functionals chosen by Jensen for evaluation [8]. Somewhat surprisingly, given the long-range correction that we previously found had

Modern flow chemistry – prospect and advantage

• Philipp Heretsch

Beilstein J. Org. Chem. 2023, 19, 33–35, doi:10.3762/bjoc.19.3

• disadvantages when moving from batch reactions to a continuous flow regime, dispersion phenomena play a detrimental role. These gradient effects occur when a stream of reagent is introduced into the reactor by pushing it with pure solvent. The reagents with well-defined concentration then leach into the solvent

• slug, leading to ill-defined stoichiometry and decrease in yield. While this axial dispersion is dependent on flow speed and residence time, only the central part of the reaction stream is under so-called steady-state conditions. To zero out these effects when a process yield is to be determined, pre

A study of the DIBAL-promoted selective debenzylation of α-cyclodextrin protected with two different benzyl groups

• Naser-Abdul Yousefi,
• Morten L. Zimmermann and
• Mikael Bols

Beilstein J. Org. Chem. 2022, 18, 1553–1559, doi:10.3762/bjoc.18.165

• % dispersion in mineral oil, 162 mg, 4.05 mmol) was added to a solution of hexol 6 (694 mg, 0.338 mmol) in anhydrous DMSO (20 mL) under a nitrogen atmosphere at room temperature. After bubbling had subsided, 2,4-dichlorobenzyl chloride (0.563 mL, 4.05 mmol) was added over four hours with a syringe pump. The

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• describe the London dispersion interactions as implemented in the Gaussian 16 program. Results and Discussion Previous electrochemical studies for triferrocenyl trithiophosphite revealed in their cyclovoltammograms three reversible one-electron peaks corresponding to stepwise oxidation of the three

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• low flow rate (10 μL/min) [43][44]. An alternative approach to obtain a narrower RTD is the reduction of the reactor diameter, as this would decrease the axial dispersion [45]. Replacing the glass column (i.d. 6.6 mm) with a PTFE capillary with a smaller inner diameter (i.d. 5/32”, 3.9 mm) resulted in

Understanding the competing pathways leading to hydropyrene and isoelisabethatriene

• Shani Zev,
• Marion Ringel,
• Ronja Driller,
• Bernhard Loll,
• Thomas Brück and
• Dan T. Major

Beilstein J. Org. Chem. 2022, 18, 972–978, doi:10.3762/bjoc.18.97

• any free energy barrier. The deprotonation and re-protonation steps are not included in our calculations. The overall exergonicity of this process which transforms four π-bonds to σ-bonds, with accompanying gains in intramolecular dispersion interactions, is −62.8 kcal/mol. IE pathway As described

• carbocation A’ is significant, due to the exchange of two π-bonds for σ-bonds, as well as gain in dispersion interactions on folding of the extended geranylgeranyl cation. Discussion Although the current calculations were performed in the gas phase without inclusion of the enzyme environment, we may still

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• water, and dried under vacuum at 60 °C. A chromatography over silica gel of this solid (cyclohexane/ethyl acetate 2:1) at 60 °C gave first a fraction containing compound 4{1,2} which was further purified by dispersion in a boiling mixture of toluene and cyclohexane (0.09 g, 3.5%) and then compound 3{1,2

The stereochemical course of 2-methylisoborneol biosynthesis

• Binbin Gu,
• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

• ]. Recent research on its chemical ecology demonstrated that arthropodes are attracted by compound 1 which helps in the dispersion of Streptomyces spores [20]. The absolute configuration of (–)-1 has been established through a synthesis from (+)-camphor [21]. The biosynthesis of compound 1 was initially

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• a method for the acetylation of isoamyl alcohol (9) catalyzed by Candida antarctica lipase B (Scheme 3) [26]. A biphasic system consisting of n-heptane and an aqueous buffer solution is used and efficiently mixed in a Corning AFRTM Low Flow reactor providing a fine dispersion of the reaction mixture

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• . General synthetic procedure for 1,3-diketones The 1,3-diketones (Figure S2 in Supporting Information File 1) were synthesized by following a literature procedure [46]. To a suspension of NaH (1.60 g of dispersion in oil, 40 mmol) in ethyl acetate (20 mL) at 0 °C was added slowly a solution of the

Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• reductive coupling of acid halides with ketones [36][37] and acetolyses of α-phenoxy-α-diazoketones [38] were also employed. Recently, F. P. Cossío et al. [39] have described a method for the preparation of benzo[b]furans by thermal heating of a dispersion of α-phenoxyketones in Al2O3. We involved the