Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions

• Udyogi N. K. Conthagamage,
• Lilia Lopez,
• Zuliah A. Abdulsalam and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192

• differences in structure and mechanical properties likely explain the distinct behavior of the rotaxane in these two membranes by influencing its optimal orientation and positioning and, consequently, its ability to modulate the dye release. Figure 6 summarizes the sulforhodamine B release from LUVs with four

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• ]rotaxanes consist of a macrocycle and an axle held together purely by mechanical bonding without covalent linkage. More complex architectures, such as [3]rotaxanes, may feature two macrocycles threaded onto a single axle or one macrocycle threaded onto two axles (Figure 1) [16][17][18][19]. Integrating

• azobenzene serves as a recognition site for an α-cyclodextrin macrocycle [22]. This material demonstrated remarkable mechanical properties, including a rupture strain of 2800%, which was attributed to the stress-dispersive sliding motion of the rotaxane cross-links. Moreover, the polymeric network exhibits

• , achieving rapid mechanical actuation (Figure 4). This example illustrates the potential of topological cross-linking in advancing the field of stimuli-responsive materials, particularly in applications requiring efficient and durable artificial actuators. Yang and co-workers reported a photoresponsive

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• green alternative to solution-phase chemistry [91]. Mechanical grinding or milling also provides a means to generate radicals via piezocatalysis [91], an emerging strategy that warrants investigation in the context of enantioselective radical reactions. Future research holds the key to addressing

Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid

• Yana I. Sakhno,
• Oleksander V. Buravov,
• Kostyantyn Yu. Yurkov,
• Anastasia Yu. Andryushchenko,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158

• -triazoles, pyruvic acid, and salicylaldehydes were studied under different conditions. Upon conventional heating, benzotriazolooxadiazocine-5-carboxylic acids were formed in the three-component reactions as single reaction products. Upon ultrasonic activation or mechanical stirring at room temperature, the

• compounds 5d and 6d). Unfortunately, all attempts to separate these mixtures were unsuccessful. However, repeating the reaction under mechanical stirring at room temperature for 72 h yielded tetrahydrotriazolopyrimidine-7-carboxylic acids 5a–c as a mixture of two diastereomers (Scheme 3, Table 2). In the

• -5-methylthio(methoxy)-1,2,4-triazoles with salicylaldehydes, and pyruvic acid can be switched between two different directions using conventional thermal heating, mechanical stirring at room temperature and ultrasonication at room temperature. The treatment under reflux conditions leads to the

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• combined with state-of-the-art multireference quantum mechanical calculations to understand the photophysical properties and mechanisms of these diazabicyclo[2.2.1]heptenes. The energetically accessible lowest excitations are nNN(σCN) → π* and range from 3.94–3.97 eV. From the >292 trajectories, the

• , thereby explaining the observed selectivities. A minority of trajectories undergo thermal conversion in the ground state, producing the minor retained housane product from inverted housane/diradical. Keywords: non-adiabatic molecular dynamics; photochemistry; quantum mechanical calculations

• preference for inversion across several derivatives of 1 [77][78]. These studies suggest that the thermal denitrogenation of diazabicyclo[2.1.1]hep-2-ene undergoes a concerted mechanism of elimination of nitrogen, while the photochemical reaction proceeds via a stepwise mechanism. Quantum mechanical

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• (O)Cl3 and glycidol were purchased from suppliers and used without additional purification. Synthesis of diglycidyl methylphosphonate (1). A 500 mL flask with 200 mL of dichloromethane, equipped with a mechanical stirrer, was cooled to −30 °C. Then, 2 equiv of glycidol (21.4 g, 0.289 mol) and 4.2

• ), 3066 (w); Anal. calcd for C7H13PO5: C, 40.39; H, 6.30; O, 38.43; P, 14.88; found: C, 40.24; H, 6.52; P, 14.79. Synthesis of diglycidyl methylphosphate (2). A 500 mL flask with 200 mL of dichloromethane, equipped with a mechanical stirrer, was cooled to −30 °C. Then, 2 equiv of glycidol (20.0 g, 0.27

• with 200 mL of dichloromethane, equipped with a mechanical stirrer, was cooled to −30 °C. Then, 3 equiv of glycidol (22.6 g, 0.305 mol) and 4.5 equiv of potassium hydroxide (25.6 g, 0.457 mol) were added to the flask. Phosphorus oxychloride P(O)Cl3 (1 equiv, 15.6 g, 0.102 mol) was added dropwise to the

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

• Kelsey Plasse,
• Valerie Wright,
• Guoshu Xie,
• R. Bernadett Vlocskó,
• Alexander Lazarev and
• Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

• are one of the major driving forces in green synthesis [1][2]. High hydrostatic pressure (HHP) activation, one of such methods, is based on mechanical compression force. The typical pressure range is 2–20 kbar that is orders of magnitude greater than the conditions traditionally employed in chemistry

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• ], medicine [3], sensing [4] and energy storage [5]. Typically, bulk graphene is obtained using a top-down approach, where graphite is exfoliated using chemical or mechanical methods [6][7]. However, this method does not provide precise control over the structure of graphene and graphenoid materials, which is

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• Sustainability, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy 10.3762/bjoc.21.33 Abstract Photomechanochemistry, i.e., the merger of light energy and mechanical forces, is emerging as a new trend in organic synthesis, enabling unique reactivities of fleeting excited states under solvent

• -minimized conditions. Despite its transformative potential, the field faces significant technological challenges that must be addressed to unlock its full capabilities. In this Perspective, we analyze selected examples to showcase the available technologies to combine light and mechanical forces, including

• developed, where additional energy is applied to increase mixing such as pulsation [26][27][28], ultrasound energy [29], segmented flow [30], or mechanical stirring [31]. In line with the recent emphasis on Green Chemistry principles [32][33], alternatives have been developed in order to reduce the amount

Quantifying the ability of the CF₂H group as a hydrogen bond donor

• Matthew E. Paolella,
• Daniel S. Honeycutt,
• Bradley M. Lipka,
• Jacob M. Goldberg and
• Fang Wang

Beilstein J. Org. Chem. 2025, 21, 189–199, doi:10.3762/bjoc.21.11

• . We expect this information to be useful for the rational application of the CF2H group in drug development and molecular design. Previous quantum mechanical calculations revealed that the CF2H···O binding energy (ΔE) ranges from 1.0 kcal/mol to 5.5 kcal/mol [14][15][18][21]. In addition, as measured

Hot shape transformation: the role of PSar dehydration in stomatocyte morphogenesis

• Remi Peters,
• Levy A. Charleston,
• Karinan van Eck,
• Teun van Berlo and
• Daniela A. Wilson

Beilstein J. Org. Chem. 2025, 21, 47–54, doi:10.3762/bjoc.21.5

• membranes. In this example by Buscema et al. it was observed that liposome vesicles can deform under mechanical stress to yield similar structures as the PSar-PBLG vesicles [32]. It was attempted to change the shape of the assembled vesicles following a similar method as previously developed for PEG-PS

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• cross-linking of the hydroxy groups on CDs could extend the molecular/material design. As the di-isocyanate macromonomer was used for long axle components, the coverage ratio of CDs in this system was 3–5%, which was significantly lower than those of other systems in 2020. The mechanical properties of

• different from that of a single CD molecule. Such an aggregation behavior of polyrotaxane induces the increase of the mechanical strength of the material or the construction of a nanosheet, which is beneficial for material application. Meanwhile, CD-based polyrotaxane requires various synthetic demands, as

Mechanochemical difluoromethylations of ketones

• Jinbo Ke,
• Pit van Bonn and
• Carsten Bolm

Beilstein J. Org. Chem. 2024, 20, 2799–2805, doi:10.3762/bjoc.20.235

• absorption of mechanical energy and they are influenced by several factors, including the lack of solvation, changes in morphology and rheology of the reaction mixtures during the milling, and variations in concentration and dielectric environment. Consequently, an increased reactivity can be achieved

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

• attached to the molecules themselves or is interacting with them. Introducing fluorescent dyes to self-assembling systems affects their chemical and mechanical stability as the hydrophobic features can destabilise the self-assembled network [18]. This reliance on fluorescence labels or dyes leading to a

• highly sensitive cantilever to measure the nanometre to sub-millimetre surface morphology. Attractive or repulsive interactions between the surface and the cantilever induce a bending force in the cantilever providing a mechanical means of probing the surface nanostructure [11]. There are various modes

• away accumulated surface electrostatic charge [30]. Furthermore, the requirement that TEM samples are prepared as thin films in order to allow electrons to be transmitted through the sample may require mechanical abrasion or ‘blotting’ of the sample to achieve this [14]. Supramolecular materials which

Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine

• Alfiya R. Gimadieva,
• Yuliya Z. Khazimullina,
• Aigiza A. Gilimkhanova and
• Akhat G. Mustafin

Beilstein J. Org. Chem. 2024, 20, 2599–2607, doi:10.3762/bjoc.20.219

• by РсМ. As described in [13] to a three-necked flask of 100 mL capacity, equipped with a mechanical stirrer, a thermometer, and a reflux condenser, containing 10 mL of distilled water, was added 0.023 mol of the corresponding uracil 1 or 4, followed by the addition of 11 mL of a previously prepared

• ) With addition of H2O2. To a three-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser containing 10 mL of distilled water was added 0.023 mol of powdered uracil 1 or 4, followed by the addition of 11 mL of a previously prepared 24% NaOH solution to the obtained

• described in [13] in a three-necked flask of 100 mL capacity, equipped with a mechanical stirrer, a reflux condenser, and a dropping funnel, 0.022 mol of compound 2 or 5 was placed, 30 mL of distilled water were added and the mixture heated to 80 °C under constant stirring. Then, 0.022 mol of concentrated

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

• computed by various methods [95]. These include substructure keys-based [96][97][98][99][100], circular [101][102][103], physicochemical [104][105][106][107], and quantum mechanical (QM) features [108][109][110][111][112]. The choice of descriptors depends on the size and scope of the dataset. For large

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

• mechanical calculations is also increasing, such as a data set that considers propargylation reactions catalysed by bipyridine N,N’-dioxide-derived scaffolds, created by Wheeler and co-workers using their AARON toolkit [21][114][115][116]. Similar to experimental data, computational data sets also lead to

• molecule either by topological or quantum mechanical descriptors. The generality of a catalyst was then assigned by considering the fraction of clusters for which the average cluster enantioselectivity of a catalyst exceeds a user-defined threshold. This threshold can be used to balance the need for a wide

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

• , the double azide addition reaction was applied to polymer crosslinking and the mechanical properties of the self-standing polymer films were compared. Results and Discussion Strain-promoted azide–alkyne cycloaddition Octadehydrodibenzo[12]annulene (DBA) with electron-withdrawing carbonyl substituents

• -standing film became insoluble due to the occurrence of strain-promoted double azide–alkyne cycloaddition (Figure 6a). The mechanical properties of the polymer films were then examined to observe the impact of crosslinking. A PVC-N3 film was prepared by a solvent-cast method on a Teflon boat. The strain

• -stress (S–S) curve of the PVC-N3 film exhibited a breakdown at the strain of >300% with a gradual increase in the stress (Figure 6b). This film did not display any yielding points (Figure 6c). Interestingly, the crosslinking with 5 dramatically changed the mechanical features. The crosslinked film showed

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• partial solubility of ethylene glycol in methoxycyclopentane as ethylene glycol could be clearly seen in the 1H NMR spectrum of the crude reaction extracts. It should also be noted that the lower isolated yields most likely reflect mechanical losses during extraction and chromatographic separation as the

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

• of chemical processes [20][21], transporting and storing molecules [22], transducing and integrating information [23] providing structural and mechanical support [24], and generating movement [25], among other functions [26]. To fold and carry out their function properly, proteins often need post

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• were thus carried out and they showed short-lived fluorescence and long-lived emission (phosphorescence) that was assigned to the triplet state of Aza-H with an energy of 2.32 eV (Figure 1A). Quantum mechanical computations of the Aza-H triplet state yielded a triplet energy of 2.17 eV (adiabatic

• Supporting Information File 72: General information, detailed experimental procedures, additional spectroscopic data, quantum-mechanical calculations, photostability and photoisomerization experiments. Funding We acknowledge generous financial support from the JGU Mainz and the German Federal Environmental

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• unique structure of fullerenes, characterized by a fully conjugated closed-cage structure, containing a mixture of hexagonal and pentagonal rings, have been recognized for the unique electronic [2][3][4], optical [5][6], and mechanical properties [7][8]. Despite the notable achievements in fullerene

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• . Rotations around each bond can also happen and we expect similar steric hindrance effects to appear. Mechanical properties of PBA-linked molecular structure on graphene Here, we discuss possible conformations of the PBA-linked molecule. Would a similar activation barrier-type potential energy surface be

• antibody protein on graphitic material by a linker. The target antigen is introduced onto the sensor chips through antibody/antigen reaction. The present study is concerned with the mechanical deformation of the linker molecule. The mechanical properties of the rotational motion are almost the same whether

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

• macroscopic analogs, exhibit mechanical motion between an open and closed conformation in response to stimuli. Such systems constitute an essential component of artificial molecular machines. This review will present selected examples of switchable molecular tweezers and their potential applications. The

• , and molecular machines. In particular, the advent of artificial molecular machines [13][14], consisting of an assembly of molecular components that perform mechanical-like motions in response to specific stimuli, has inspired the development of stimuli-responsive molecular tweezers, which have

• , the incorporation of responsive functionalities into molecular tweezers not only provides significant benefits in catalysis for the development of switchable catalysts but also extends their utility to molecular magnetism, where magnetic switches exploit mechanical motion, and to molecular electronics