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

• system and enable dynamic ligand formation due to the reversibility of the hydrazone bond formation [40]. More recently, Vives and co-workers have developed a family of terpyridine-based tweezers bearing metal–salphen complexes as functional units (Figure 9). Using metal complexes as arms brings

• ligands. The reversibility of the opening/closing process was achieved in situ by the addition and removal of CO yielding one of the first examples of allosteric regulation in artificial systems. Dissymmetric molecular tweezers are also accessible with high selectivity using two different hemilabile

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• considered: solubility in the chosen solvent, absorption spectrum, oxidation potential, and the reversibility of the sacrificial donor oxidation. As the sacrificial donor is a reactant in the photoreduction reaction of carbon dioxide, it needs to be highly soluble in the solvent used. It also needs to have a

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• . The reversibility of the acid hydrolysis is quite typical for furans and is more pronounced for di- and polysubstituted furans, due to the higher stability of the latter [49][50][51]. 3-(2-Oxopropyl)piperidin-4-one 5a could be involved into the Paal–Knorr pyrrole synthesis in a one-pot manner. Thus

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

• ]. Meanwhile, an important difference is the reversibility of the oxidation observed at low potential scan rates (100 mV/s) for the complexes (GlyNi)L7 and (ΔAlaNi)L7 (see Figure 4), in contrast to their t-Bu-free analogs. The similarity of the potential values for the complexes derived from L1 and L7 allows

• reversibility can be reached at scan rates above 20 V/s allowing the E1/2 estimation. Similarly to previously studied complex (ΔAlaNi)L1 [36], electron transfer to (ΔAlaNi)L7 is mainly ligand centered. The DFT-estimated LUMO is formed as an overlap of the π antibonding orbitals of the dehydroalanine and imine

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

• Robert N. Goldberg,
• Robert T. Giessmann,
• Peter J. Halling,
• Carsten Kettner and
• Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• -butylammonium hexafluorophosphate as the supporting electrolyte (Figure 3a and Table S2 in Supporting Information File 1). The oxidation and reduction of both emitters showed good reversibility, which is beneficial for better performance in LEEC devices [31]. The oxidation potentials, Eox, determined from the

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• organocatalytic units embedded in polymers for catalysis in small molecule systems have been discussed [15][19][20]. Moreover, the ability of force to deform the reaction energy landscape and modulate the reversibility of the reactions within proteins has been demonstrated. For example, mechanical force was used

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• rates (50, 100, 200, 400, 600 and 1000 mV s−1) and reversibility of the oxidation process by repeated potential cycling (20 cycles). For both OTK-2 and OTT-2, the Epaox remained steady at different scan rates while the anodic peak current (Ipa) increased with the increase in scan rate. The Ipa showed a

• negligible change during 20 cycles at a scan rate of 100 mV s−1, indicating diffusion control and good reversibility of the oxidation process (Figures S2b,c and S3b,c, Supporting Information File 1). The highest occupied molecular orbital (HOMO) energy level versus vacuum level was estimated from the E1/2ox

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• more negative. This can be attributed to the presence of the electron-withdrawing keto groups [3][20]. In contrast to compounds 2–4, which showed poor reversibility for oxidation and reduction, EtH-T-DI-DTT shows excellent electrochemical stability. Two sequential reversible oxidations can be seen in

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• 98 reacted with the copper(I) ions to afford [Cu2(98)2]2+ representing again a reservoir for a rotator. Based on the stoichiometry of the above equation, two equiv of copper(I) ions were liberated. Since the released free copper(I) ions generated problems with reversibility of the transformation, 1

• [133]. In order to test the reversibility, both switches were toggled by adding and removing the iron(II) ions over 2.5 cycles demonstrating that ON/OFF catalysis was reversible and reproducible. Interestingly, the nanoswitches [Cu2(130)]2+ and [Cu2(131)]2+ (1:1) could be selectively addressed in the

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• compared to other self-healing supramolecular polymers, e.g., metallopolymers [25]. Supramolecular polymers feature certain temperature ranges, in which the noncovalent bond is activated. The degree of reversibility can be determined by the supramolecular bond lifetime [26]. For example, a study regarding

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• complex interplay of attractive interactions enables fine-tuning of the phase transition temperature itself, as well as the sharpness, switching amplitude and reversibility of the transition for a desired application [6][50][51]. Today there are several excellent reviews offering synthetic guidelines for

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

• Sergey V. Norkov,
• Anton V. Cherkasov,
• Andrey S. Shavyrin,
• Maxim V. Arsenyev,
• Viacheslav A. Kuropatov and
• Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

•  2. The high extent of enolization of 1,3-diketones results in lower nucleophilicity of the active methylene function. This fact enhances the reversibility of the dithiocarboxylation of sodium acetylacetonate. It is known that dithiocarboxylates and gem-dithiolates can lose CS2 resulting in active

• methylene compound salts [17]. Due to the reversibility of dithiocarboxylation, the reaction mixture contains some amount of sodium acetylacetonate, which can attack the chlorine atom at the backbone of 2 to give the substitution product (Scheme 2). According to the reported data, the quinone-methide form

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

• are reversible. Quantitatively, comparing the absorbance of Flavy before and after completion of the different cycles shows that close to 75% of Flavy revert back (data given in Table 1). Likely the reason for the incomplete reversibility is a photoprotective effect which hinders the open form Cc to

• state C the size of the assemblies decreases to RH = 161 nm. At the same time, the structure changes back to a sphere (Figure 5c). To make a statement on the reversibility, it is necessary to compare this state of cycle I with the second state of cycle II. Cycle II shows a decrease in size from RH = 192

• DLS and again show the reversibility of both cycles. As reported for other systems, the structures in AFM are substantially smaller than in DLS due to the shrinking upon drying in the AFM sample preparation [40][60][83][84][85]. Further, the ζ-potential was determined to understand the changes in the

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• reversibility was achieved by the addition of the rhodium porphyrin 19 that reversed the system reviving the state SelfSORT-I. Since both self-sorted states exhibited a distinct fluorescence due to the changes at the zinc porphyrin sites, luminescence was used for the selective detection of DABCO in a mixture

• transformation 32 + 33 → 34 was observed, because the copper(I) is deeply embedded in [Cu(30)]+. This double self-sorting showed a full reversibility upon the addition and removal of zinc(II) ions along with ON/OFF catalytic behavior and reproducible yields of the product 34 (36%) in two subsequent cycles. An

• catalytic behavior showed a full reversibility up to three cycles and provided 45%, 43%, and 41% yield, respectively, in subsequent cycles. The small decrease of the yield over three release/capture cycles was explained by a minor degradation of silver(I), a phenomenon equally seen in the emission channel

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system

• David Liese,
• Hans Henning Wenk,
• Xin Lu,
• Jochen Kleinen and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2020, 16, 2820–2830, doi:10.3762/bjoc.16.232

• Information File 1) shows the thermal reversibility of the gel formation process. The phase transition temperature can be obtained from the temperature sweeps and is defined as the temperature where the dynamic moduli intercept. In an alternative representation, the phase transition temperature can also be

• demonstrate the thermal reversibility of the gelation process. There are peak maxima at the heating and cooling phases that can be assigned to the formation of the gel structure and its decomposition. For the heating phase, a maximum was found at 45 °C, the endothermic melting process of the sample. In the

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• problems associated with the reversibility of enzymatic phosphorolysis/synthesis reactions, along with the solubility of heterocyclic bases and accessibility of PF-1Pis. Despite all this, in a number of cases these problems have been successfully solved and, as a result, the desired base and/or sugar

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

• ), 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

Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties

• Anka Utama Putra,
• Deniz Çakmaz,
• Nurgül Seferoğlu,
• Alberto Barsella and
• Zeynel Seferoğlu

Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189

• light indicated that the dye was deprotonated. Indeed, the addition of only 5 equiv of TFA regenerated the light yellow color of the solution indicative for the reversed protonation of 12. All dyes, except 8, showed this reversibility. Furthermore, the limits of detection (LOD) and quantification (LOQ

• reversibility test using TFA showed that all Schiff base-based dyes, except 8, could be brought to the initial state and hence marked their repeatability usage for every single analysis process. The interaction of a Schiff base and hydroxide anion in aqueous environment was conducted successfully using dye 8

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

• was E1/2 = +0.380 V vs SCE showing that rotaxane 1a retained the redox properties of the parent ferrocene [21][22]. Importantly, the full reversibility of the one electron oxidation–reduction process attested to the stability of the electroactive system. Solid-state X-ray structure The solid-state

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• corresponding to the free iminoxyl radical, which indicates the reversibility of dimerization [53]. During the oxidation of pivalic aldoxime 1e by Ag2O, the formation of nitrile oxide 6e was observed, which then slowly dimerized to the corresponding furoxan 7e. The kinetics of the decomposition of dialkyl

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• ) due to the low reversibility of the double bond formation. Initially, the photocatalytic oxidative amine coupling was selected as a reaction model [103]. The authors observed that the imine-based Por-COF-1, decomposed completely, and no target product was detected. Nevertheless, the Por-COF-2

Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands

• Shohei Mimura,
• Sho Mizushima,
• Yohei Shimizu and
• Masaya Sawamura

Beilstein J. Org. Chem. 2020, 16, 537–543, doi:10.3762/bjoc.16.50

• step (C to D) is reversible. Finally, protonation of D by t-AmOH gives the product 2 and silyl ether (EtO)2MeSiOt-Am, regenerating the phenoxy copper(I) complex A. Due to the reversibility of the 1,4-hydrocupration, the choice of the alcoholic protonation reagent affects both the reactivity and

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• shown to realize photoinitiated controlled/living radical polymerization of various monomers in metal free conditions. In the visible region, several dyes (fluorescein, eosin Y, erythrosin B) worked well to mediate ATRP in the presence of amines [72]. The reversibility of the electron transfer steps

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• effects, due to its many survival-critical roles, as well as non-functionality of the modified tubulin product. For example, knockout approaches have only been described for single isoforms of α/β-tubulin, and these cannot deliver the dynamic reversibility and effect-specificity that is required for