Photoluminescence color-tuning with polymer-dispersed fluorescent films containing two fluorinated diphenylacetylene-type fluorophores

• Kazuki Kobayashi,
• Shigeyuki Yamada,
• Motohiro Yasui and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2682–2690, doi:10.3762/bjoc.20.225

• white-light-emitting materials. Keywords: energy transfer; fluorinated diphenylacetylenes; photoluminescence; polymer-dispersed films; white luminescence; Introduction Luminescent materials in lighting and display devices have become indispensable in daily life [1][2][3]. In recent years, organic

• electroluminescent devices have attracted significant attention as lightweight and energy-saving optical devices, and there has been a strong demand for the development of luminescent materials. Until now, the design of solid-state light-emitting materials has not been established, and therefore, their development

• photoluminescence (PL) have been developed, whereas red PL with PL wavelengths in the long wavelength region is considered difficult to achieve owing to the energy gap law [11][12][13]. Over the past few decades, our group has been vigorously pursuing the exploration of functional molecules with a linear

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• -D3(BJ)/def2-SVP computational level. Single point energy calculations on the optimised structures were run at the B3LYP-D3(BJ)/def2-TZVP level to obtain more accurate electronic energies. The reported free energies in this section correspond to the sum of the triple-zeta electronic energy and the

• free energy correction at double-zeta. The kinetics of some reactions were calculated, applying the transition state theory [40]. Within this theory, the rate constant of an elementary reaction with the free energy barrier ΔG‡ is given by Equation 1, where k is the rate constant in s−1, kB is the

• performance, for example, the reaction rate, is displayed as a function of the catalyst–substrate interaction, for example, the adsorption energy when considering a heterogeneous catalyst (Figure 1A). The resulting plot exhibits a volcano-like shape consisting of at least two slopes with the best-performing

Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study

• Stiliyana Pereva,
• Stefan Dobrev,
• Tsveta Sarafska,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221

• ] hydration was employed: the geometries of γ-CD, water molecule/clusters and hydrated complexes were optimized at the M062X/6-31G(d,p) theoretical level and the electronic energy, Eel, of each structure was estimated. To obtain more accurate energies, single point calculations were made at the M062X/6-311++G

• is described in the first two papers in the series on the hydration of α-CD and β-CD, respectively [13][14]. The performed M062X/6-31G(d,p) frequency calculations for each structure ascertain that the wave function corresponds to a minimum on a potential energy hypersurface, but also yields the

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• supramolecular gels. Keywords: characterisation; electron microscopy; gelators; small angle scattering; supramolecular materials; Introduction Supramolecular gels are a versatile class of materials, and are of interest in many diverse applications from energy storage to cell culture [1][2]. The versatile

Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

• Yuki Yamamoto,
• Yuki Konakazawa,
• Kohsuke Fujiwara and
• Akiya Ogawa

Beilstein J. Org. Chem. 2024, 20, 2577–2584, doi:10.3762/bjoc.20.216

• aryl radicals without photocatalysts, and the trapping with diselenides afforded a variety of diaryl selenides [59]. Based on these backgrounds of our studies and the fundamental property, i.e., the weak bond dissociation energy of the Ph–Bi bond (46 kcal/mol) [60], we hypothesized that aryl radicals

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• S19 in Supporting Information File 1). Theoretically performed energy decomposition analysis (EDA) based on FMO2-MP2 using the basis set of NOSeC-V-DZP with MCP [37][38][39][40] for the anion and closely located 2+, as suggested by Hirshfeld surface analysis, revealed that short counteranion–TATA

• , respectively (Figure 8a,b and Figures S29 and S30 in Supporting Information File 1). The energy values for 2+-PCCp− are larger than other sets of ion pairs located at the side of TATA+ showing Etot of −63.1 kcal/mol. On the other hand, another proximally located ion pair in 2+-B(C6F5)4− showed similar Etot

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• and development of a visible light-assisted modular photo-flow reactor with a seamlessly integrated post-synthetic work-up procedure enabling the efficient synthesis of dihydropyranones from furfuryl alcohols. The reaction uses sun light as green energy source, and the novel photo-flow reactor

• batch protocol. This electrochemical batch process utilizes electricity to enhance the vibrational energy of the substrate for the completion of the reaction and involves a noble metal, such as Ni-DVBP as an electrode. Also, the batch technique encounters a serious issue when considered for bulk

• challenges. To address these points, a novel continuous photo-flow platform for the Achmatowicz reaction including integrated post-synthetic work-up in a safe and faster manner with less intervention of human was developed (Scheme 1 (2)). This process involves a nature abundant energy source such as sun

Machine learning-guided strategies for reaction conditions design and optimization

• Lung-Yi Chen and
• Yi-Pei Li

Beilstein J. Org. Chem. 2024, 20, 2476–2492, doi:10.3762/bjoc.20.212

• ]. Most of the existing methods were originally designed for predicting reaction properties (such as activation energy, reaction enthalpy, etc.) or classifying reactions, but they can be potentially adapted for reaction conditions prediction by modifying the output layer of the model. Both global reaction

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• in a chloroform solution, using the polarizable continuum model (PCM) [75]. A natural bonding orbital (NBO) analysis was performed to study the effects of hyperconjugation from C–F antibonding orbitals [76]. First, dipole moments, enthalpy and Gibbs free energy differences between 1C4 and 4C1 chair

• are nearly degenerate. In solution, the picture is much clearer: the 4C1 structure is always lower in enthalpy and Gibbs free energy, which corresponds with the experimental measurements. One can see that the gap between the two structures tends to decrease as the halogen becomes larger (the minor

• described the synthesis and conformational analysis of halogenated pyran analogues of ᴅ-talose. All analogues adopt standard 4C1-like conformations both in solution and in the solid-state. The conformations were corroborated using DFT calculations by looking at the energy, enthalpy and Gibbs’ free energy

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• organometallic species [16][17][18][19]. At least in part, its high reactivity was considered to be due to the significantly lower-lying LUMO energy level by the attachment of electron-withdrawing trifluoromethyl (CF3) and ethoxycarbonyl groups [20]. As we previously pointed out [10][21], the effective

• ). The subjection of the compounds 1h and 1i to the standard conditions described above resulted in high recovery of the substrates, which could be explained by their higher LUMO + 1 energy levels responsible for the epoxidation [43]. Extensive decomposition was observed in the case of 1j even in a

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• modeling of this reaction was performed based on the theory of NO2+ attack, with the activation energy and pre-exponential factor determined. Finally, based on the response surface generated by the kinetic model, the reaction was optimized with a conversion of 87.4% under a sulfuric acid mass fraction of

• effects of mass and heat transfer. According to the mixing principle, there are active mixers and passive mixers. Passive mixers do not require overly complex equipment and external energy inputs and are extensively used in continuous flow reactions [20][21]. Passive mixers enhance the passive mixing of

• values of k0 at different temperatures, the activation energy for the electrophilic attack of NO2+ on the IO can be calculated by the Arrhenius equation: where R is the molar gas constant and T denotes the temperature in Kelvin, and Ea and A are the activation energy and pre-exponential factors for the

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• , an observation that is in good agreement with previously obtained data on bisurea catalysts [36]. To further distinguish between the SN1 and SN2 mechanisms, the authors performed an in silico simulation of the non-catalysed reaction to determine the possible potential energy surface and found that

• , in the COBI–imine complex 74 it appears at 8.41 ppm, while in the imine TfOH salt 75 it shows at 9.24 ppm. This detailed NMR investigation sparked further interest in the structure of the transition state of this reaction. An analysis of the potential energy profiles of the two hypothetical pathways

Tandem diazotization/cyclization approach for the synthesis of a fused 1,2,3-triazinone-furazan/furoxan heterocyclic system

• Yuri A. Sidunets,
• Valeriya G. Melekhina and
• Leonid L. Fershtat

Beilstein J. Org. Chem. 2024, 20, 2342–2348, doi:10.3762/bjoc.20.200

• high-energy materials [8][9][10][11][12][13]. Moreover, furazan derivatives possess antiproliferative, antibacterial, antiparasitic and antiviral activity [14][15][16]. On the other hand, furoxans referred to as unique heterocyclic compounds that exhibit NO-releasing properties under physiological

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• synthesis. The higher-energy collisional dissociation (HCD) releases the characteristic reporter ion at m/z 126.1277. In case the electron-transfer dissociation (ETD) is used the DMP-tag yields the reporter ion at m/z 114.1275. Of note, although ETD is more selective towards fragmentation of the peptide

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• ][5]. The transient impact of kinetic energy, channeled into the reaction, facilitates overcoming the constraints inherent in equilibrium models. Thus, employing limited substrates could potentially yield diverse products through a simple alteration of conditions, compared to solvent-based methods [6

• enhancing the reactivity of a relatively inert acceptor does not necessarily lead to increased reaction rates, involves the use of more reactive nucleophiles. In this context, varying the stabilization energy of carboxylic acid derivatives by switching from oxoesters to thioesters is the significant

• primary amines for this purpose to enable activation of the enone system. Such a method lowers the energy of the LUMO orbital and subsequently reduces the energy barrier between the nucleophile's HOMO orbital resultingly, expedites the entire transformation [38]. Moreover, the presence of the stereogenic

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

• by observing the influence of substituents on a reaction outcome. However, Hammett parameters have shown to not fully describe observed trends. Therefore, complementary representations capturing other properties of a molecule have been derived (vide infra) [28]. While traditional linear free energy

• Drawing inspiration from linear free energy relationships, MLR models, pioneered by Norrby and co-workers [83] and later further developed by Sigman and co-workers [69][82], are commonly used for the prediction of enantioselectivity. In such models, the substrates, catalysts, and other relevant reaction

• and type II’ β-hairpin. Even though the latter was consistently lower in ground state energy (up to 6 kcal/mol for some catalysts), predictive models for enantioselectivity were found for both catalyst conformers in separate MLR models. For organophosphorous ligands of transition metal complexes, the

Synthesis and reactivity of the di(9-anthryl)methyl radical

• Tomohiko Nishiuchi,
• Kazuma Takahashi,
• Yuta Makihara and
• Takashi Kubo

Beilstein J. Org. Chem. 2024, 20, 2254–2260, doi:10.3762/bjoc.20.193

• two anthryl moieties (Figure 3b, Supporting Information File 1, Figure S1). DFT calculations for structural optimization revealed that the energy difference between two DAntM radical structures with different spin positions, spin localization at the central sp2 carbon and on the anthryl group, is

• small about 1.18 kcal mol−1 (Supporting Information File 1, Figure S2). To investigate the activation barrier of this equilibrium, potential energy curve by changing the dihedral angle θ of one anthryl group was calculated. The transition state was calculated with the dihedral angle θ = 30.6° and the

• activation barrier is only 2.94 kcal mol−1 (Supporting Information File 1, Figure S3). Thus, these two structures are likely in equilibrium and rapidly exchange with each other in solution. The energy difference between DAntM dimer (head-to-head σ-dimer) and DAntM radical monomer was also evaluated, showing

Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression

• Tabea Bartsch,
• Stephan Lütz and
• Katrin Rosenthal

Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192

• nucleotides and amino acids, as well as energy molecules, salts, buffer, etc., are added. After successful protein synthesis, further substrates can be added for an enzyme activity assay. Although mimicking of cell-like conditions is an approach for optimization, the physical and chemical properties of CFPS

• encoding for the target protein, amino acids and nucleoside triphosphates as substrates, an energy regeneration system and other additives such as polyethylene glycol (PEG) [9]. Although CFPS has been used and improved since the 1960s, there are challenges in its application such as low production volumes

• systems has mainly focused on individual components: the energy regeneration system, the cell extract itself, or individual buffer components [13][14]. For example, the importance of optimizing the concentrations of these reaction components has been demonstrated for four different CFPS systems, in which

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• followed a second-order reaction. Since no monoadducts were formed, the rate-determining step is the first azide addition. Based on this fact, the activation energy (Ea) of the reaction between 5 and benzyl azide in CDCl3, determined by the Arrhenius plots, was 60.9 kJ mol−1 (Figure 3). This value was

• . (a) Strain-promoted azide–alkyne cycloaddition between DBA 5 and benzyl azide and (b) 1H NMR spectral change at 30 °C in CDCl3. Arrhenius plots of the rate constants for the reaction between 5 and benzyl azide in CDCl3. Proposed reaction mechanism for the formation of compound 6a. Free energy

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• ), organogels, molecular wires, self-assembly and so forth [14][15][16][17][18][19][20][21][22][23][24][25]. Moreover, nowadays these invaluable compounds have also received great attention of supramolecular chemists, and finds applications in sensing, catalysis, donor–acceptor systems, energy transfer and

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• fine chemical and pharmaceutical industries [9]. The limitation of homogeneous catalysts, however, is their complex, time-consuming and energy-intensive recovery and subsequent recycling. Therefore, synthetic modification of catalysts is a commonly used method to aid their recovery. Obstacles to the

• ] reactions. POFs [102] are hydrocarbon systems that contain pores, of which COFs are a subgroup. POFs are widely applied in the fields of gas adsorption and storage, the separation of gases, catalysis, energy storage, photocatalysis, etc., and have many different types, such as hyper-cross-linked polymers

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• aware of resource recycling, and promote the use of natural energy [16]. The following three methods are generally used to generate heteroatom radicals (E•) (Scheme 1). In method 1, E• is generated by hydrogen abstraction from E–H by cyanoisopropyl radicals generated by thermal decomposition of 2,2

• , when using sunlight, which is an inexhaustible natural energy, it is expected to be the most environmentally friendly method. The homolysis of E–E upon visible light irradiation is induced by exciting one electron of the isolated electron pair on E to the anti-bonding orbital of the E–E-bond (σ

• perform. In contrast, tris(trimethylsilyl)silane, (Me3Si)3SiH, has a bond dissociation energy similar to that of n-Bu3SnH (74 kcal/mol) and can be used as an efficient reducing agent/mediator. Radical addition of group 13 compounds to isocyanides Boron, a group 13 typical element, also lacks a non

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

• ), skew (S), and half-chair (H) conformations (Figure 1). Among them, chair’ shapes typically have the lowest energy and are thus preferred, except few cases in which different conformations can exist in a dynamic equilibrium, as for the iduronic acid that can adopt three low-energy solution conformations

• simulations, it is fundamental not only to build their 3D structure but also to choose the appropriate force field, that is a set of empirical energy functions and parameters used to calculate the potential energy of a system as a function of the molecular coordinates. The collection of equations and

• field of computational chemistry and biochemistry: 1. AMBER [56]: AMBER (https://ambermd.org/) is the acronym for "Assisted Model Building with Energy Refinement", and it is an open-source software widely employed for molecular modelling and simulation. It is known for its stability, user-friendly

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• guidelines for future X-ray experiments using photoswitchable molecules, which can aid more accurate understanding of these materials for application in solar energy storage, catalysis or controlled drug delivery. Keywords: arylazopyrazole; azobenzene; micelle; photoswitch; X-ray; Introduction The design

• of smart materials whose properties can be controlled using external stimuli is of significant interest for diverse applications spanning soft robotics [1], energy storage [2] and drug delivery [3]. Light is an ideal stimulus as it is non-invasive and can be administered selectively with high

• greater using low-energy X-rays (8 keV) due to their greater photoabsorption in water, thus leading the authors to conclude that higher energy (≈36 keV) should be used for future small-angle X-ray scattering (SAXS) experiments on photoswitchable systems. However, this may not always be achievable