Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

Co-crystallization of an organic solid and a tetraaryladamantane at room temperature

• Fabian Rami,
• Jan Nowak,
• Felix Krupp,
• Wolfgang Frey and
• Clemens Richert

Beilstein J. Org. Chem. 2021, 17, 1476–1480, doi:10.3762/bjoc.17.103

• evaporation or diffusion. The implications for generating other co-crystals of two solids are briefly discussed. Keywords: adamantanes; crystallization; organic solids; structure elucidation; X-ray crystallography; Introduction Obtaining a crystal suitable for X-ray crystallography can be a challenge for

• instead. It is often unclear whether crystallization is too slow or too unfavorable to occur. There are several approaches to overcome the reluctance of some organic compounds to crystallize. Among them are the crystallization of small molecules at very low temperatures [5][6][7], and the diffusion into a

• conventional approach, using dichloromethane as solvent and slow evaporation or diffusion of a poor solvent into the dichloromethane solution to obtain co-crystals. Two such solvent-based crystallization runs produced the co-crystal structures shown in Figure 2. For TDA, 5 mg of the chaperone and 1 mg of

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring

• Cansu Esen and
• Baris Kumru

Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92

• take the advantage of entrapped water that might provide the opportunity to control the water retention. Unfortunately, during the photomodification, diffusion of vTA molecules has driven the water molecules outside the network. Despite this fact, the wet-modified sample resulted in a fair water

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• Dimé et al. [58]. Crystallography Crystals were grown using techniques following the protocol developed by Hope [59]. Crystals were either grown by allowing the solvent to slowly evaporate over time or by a liquid:liquid diffusion process. The crystal was mounted on a MiTeGen MicroMount and single

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• cells (Figure 2B and Supporting Information File 1, Figure S4). Passive diffusion of the LNPs with the G-3 aptamer alone through a transwell insert without hCMEC/D3 cells appears to show higher uptake in the HeLa cell line but lower uptake in the TZM-bl cell line in comparison to the transwell insert

Synthetic reactions driven by electron-donor–acceptor (EDA) complexes

• Zhonglie Yang,
• Yutong Liu,
• Kun Cao,
• Xiaobin Zhang,
• Hezhong Jiang and
• Jiahong Li

Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67

• electron transfer and forming a pair of radical ions trapped in the solvent cage. The pair of radical ions escapes the solvent cage by diffusion to give radical ions, which could initiate chemical reactions or reverse electron transfer (Scheme 1) [6]. The continuously increasing demand for sustainable

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• ][10]. Plastic materials are ubiquitous in our everyday life, which accounts for a global production of plastics of around 360 million tons in 2018 [11], of which more than 60% are disposed [12][13]. As a consequence, pollution from plastics is impressive, resulting in the diffusion of microplastics

Synthesis and physicochemical evaluation of fluorinated lipopeptide precursors of ligands for microbubble targeting

• Masayori Hagimori,
• Estefanía E. Mendoza-Ortega and
• Marie Pierre Krafft

Beilstein J. Org. Chem. 2021, 17, 511–518, doi:10.3762/bjoc.17.45

• faster diffusion of the former lipopeptides to the interface and by their larger value of πeq, hence a lower surface tension at the bubble surface. The enhanced MB stability over time and the fact that the half-life increases with fluorocarbon chain length support the view that stabilizing interactions

• -lives are obtained with the hydrocarbon analog. Our results establish that a fluorination of the precursors of targeting ligand–peptide conjugates can considerably facilitate microbubble generation due to faster diffusion to the air/water interface, and augment their stability through interfacial

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

• Vladimir Kubyshkin,
• Rebecca Davis and
• Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

Au(III) complexes with tetradentate-cyclam-based ligands

• Ann Christin Reiersølmoen,
• Thomas N. Solvi and
• Anne Fiksdahl

Beilstein J. Org. Chem. 2021, 17, 186–192, doi:10.3762/bjoc.17.18

• , due to sample decomposition. Attempts to obtain crystals for X-ray analysis by slow diffusion of n-pentane into a DCM solution of the complexes were unsuccessful. Catalytic activity For evaluation of the catalytic ability of the new Au(III) complexes, alkyne carboalkoxylation [47][48] and

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

• fully revert back when bound in the assemblies. To investigate how these differences in molecular building block structure affect the assembly nanoscale size and structure, dynamic and static light scattering (DLS, SLS) were performed. DLS measures the intensity fluctuations caused by the diffusion of

• electric field autocorrelation function g1(τ). By a regularized inverse Laplace transformation, the electric field autocorrelation function g1(τ) was transformed into the distribution of relaxation times A(τ). The apparent diffusion coefficients Dapp were calculated by Equation 3 The diffusion coefficients

Control over size, shape, and photonics of self-assembled organic nanocrystals

• Chen Shahar,
• Yaron Tidhar,
• Yunmin Jung,
• Haim Weissman,
• Sidney R. Cohen,
• Ronit Bitton,
• Iddo Pinkas,
• Gilad Haran and
• Boris Rybtchinski

Beilstein J. Org. Chem. 2021, 17, 42–51, doi:10.3762/bjoc.17.5

• ). Convenient control over the structure and function of organic nanocrystals can enhance their utility in new and developed technologies. Keywords: aromatic amphiphiles; exciton diffusion; organic nanocrystals; perylene diimides; self-assembly; Introduction Semiconductor and metal nanoparticles exhibit size

• nanocrystals with a tunable aspect ratio. These systems are quite uniform and exhibit morphology-dependent photonics: strikingly, divergent exciton diffusion properties as a function of the shape. Results and Discussion Following our interest in the self-assembly of PDI derivatives, we employed compound 1, a

• sample was measured, showing exciton dynamics very similar to the original 5% THF sample (Table 1 and Figure S9B, Supporting Information File 1). In order to estimate the exciton diffusion coefficient and the diffusion length, we used an analysis method employed in our previous work [36] and based on a

Controlled decomposition of SF₆ by electrochemical reduction

• Sébastien Bouvet,
• Bruce Pégot,
• Stéphane Sengmany,
• Erwan Le Gall,
• Eric Léonel,
• Anne-Marie Goncalves and
• Emmanuel Magnier

Beilstein J. Org. Chem. 2020, 16, 2948–2953, doi:10.3762/bjoc.16.244

• to a large decrease of the capacitive current and avoids IR drop effects. The array of Pt microdiscs offers the advantage of summing the current intensity of each microelectrode, thus increasing the sensitivity of the resulting current [25]. Whereas a planar diffusion is observed onto classical

• electrode (size >0.1 cm2), a hemispherical diffusion is expected with a microdisc electrode due to the contribution of the current diffusion by edge effects. The mass transport regime is then drastically modified on microdisc electrodes and can be adjusted in accordance with the polarization time by

• current of diffusion (id), which is directly proportional to the bulk concentration of the electroactive substance (C∞), its diffusion coefficient in the solvent (D), the number of electrons exchanged in the electrochemical process (n), and the radius of the microelecrode (r) and F the Faraday constant

Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• study, we found that the reactivity depended more upon diffusion phenomena in the crystalline parts of the material than on the increase in the surface area of the CD particles resulting from grinding. Keywords: beta-cyclodextrin; chemoselectivity; grinding; mechanosynthesis; reactivity; Introduction

• ), the ratio of mono-substituted β-CDMts to poly-substituted β-CDMts derivatives increased over time, as depicted in Figure 7. This result is probably due to the homogeneous diffusion of KOH within the solid mixture facilitating the deprotonation of a larger number of β-CDs rather than only a few of them

• (Supporting Information File 1, Table S3). Accordingly, it appeared that different models seemed appropriate to picture the reaction kinetics, meaning that the process probably results from various contributions, including nucleation, geometrical contraction, diffusion and reaction-order models. However, one

Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

• Henrik Hupatz,
• Marius Gaedke,
• Hendrik V. Schröder,
• Julia Beerhues,
• Arto Valkonen,
• Fabian Klautzsch,
• Sebastian Müller,
• Felix Witte,
• Kari Rissanen,
• Biprajit Sarkar and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209

• Information File 1). Slow diffusion of CH3CN into a concentrated solution of NDIC7 in CH2Cl2 yielded single crystals suitable for X-ray diffraction (Figure 2b). The macrocycle displays a folded conformation in the solid state due to the flexible linker, featuring an intramolecular NDI/naphthalene stacking

• ), which can be explained by diffusion and comproportionation of the dianion, as it was observed earlier for other NDI2− species [59]. Applying more positive potentials gradually converts the spectra back to the initial forms, which confirms the reversibility of the reduction processes. Overall, the

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• the diffusivity, kinematic viscosity, reactor volume, stirrer speed, etc. For a laminar flow in microstructured reactors, the characteristic mixing time can be calculated by the Einstein–Smoluchovski equation (Equation 6). Due to the short diffusion distances, complete mixing can be achieved rapidly

• . That is the reason why microreactors are suitable for reactions with a high intrinsic reaction rate [11]. where tm is the characteristic mixing time, L is the diffusion path, and D is the molecular diffusivity. The relative importance of the characteristic mixing time in microreactors to the

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• -lived and can exist beyond the timeframe of diffusion, to be leveraged in photosensitization. Intermolecular energy transfer from T1{PS} to the substrate excites it from its ground singlet state S0{Sub} to its excited triplet state T1{Sub}. This intermolecular energy transfer process, known as TTET

Automated high-content imaging for cellular uptake, from the Schmuck cation to the latest cyclic oligochalcogenides

• Rémi Martinent,
• Javier López-Andarias,
• Dimitri Moreau,
• Yangyang Cheng,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2020, 16, 2007–2016, doi:10.3762/bjoc.16.167

• added to minimize the passive diffusion across the membrane and to maximize the solubility in water. Biotin was used to interface the transporter and streptavidin to probe the COC-mediated protein delivery. A chloroalkane, finally, was needed for the HC CAPA. The trifunctional transporter 23 was first

Design, synthesis and application of carbazole macrocycles in anion sensors

• Alo Rüütel,
• Ville Yrjänä,
• Sandip A. Kadam,
• Indrek Saar,
• Mihkel Ilisson,
• Astrid Darnell,
• Kristjan Haav,
• Tõiv Haljasorg,
• Lauri Toom,
• Johan Bobacka and
• Ivo Leito

Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

• and the ability to target a larger variety of ions compared to e.g. glass. Plasticizers may be required to improve transmembrane diffusion rates unless the polymer is self-plasticizing. Plasticized poly(vinyl chloride) (PVC), which was used in this study, is an example of a commonly used membrane

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

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

• mass transport limitations, the circumstance in which a process becomes diffusion-limited and independent of the catalyst efficiency [43]. This is often thought of as an “engineering problem” by chemists, which will be solved through the reactor design [52], but smart design of the HPCat structure and

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• continuous and stable generation of iPrMgCl⋅LiCl (≈100 mmol) in the steady state under similar ODR prototype conditions. A certain volume of the starting material solution (6 mL) was discarded to prevent the dilution of iPrMgCl⋅LiCl at the beginning and at the end of the experiment due to solvent diffusion

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• with the lifetimes of both components in the ns range. Thus, compounds 2 and 3 were characterized by prompt fluorescence and no delayed fluorescence was observed. The double-exponential decays were apparently related to the spectral diffusion (exciton migration and localization at lower energy states