Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation

• Zhihua Liu,
• Ya-Zhi Chen,
• Ji Wang,
• Qingling Nie,
• Wei Zhao and
• Biao Wu

Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68

• interactions between K+ and C=O moieties [31], similar to these seen in the single crystal structures of KF and K2CO3 complexes. These provide a promising opportunity that can be used to identify the cooperative interaction underpinning complexed ions in dual-host strategy-based extraction. To do this, the

• − was 4:5:4:2 in the crystalized structure. Like the structure of K2SO4 complexes [31], one Cs+ cation is encapsulated by 18-crown-6 and further stabilized by one ion-dipole interaction with the O=C unit of the hexaurea receptor. The Cs···O distance is measured at 3.2 Å. The other two Cs+ cations are

• by 1H NMR titrations in DMSO. The resulting complexes after solid–liquid extraction were also characterized by 1H NMR spectroscopy (Figure 3), showing consistent anion binding profiles. By comparing with free hexaurea receptor L, the chemical shifts of the urea units N–H in the obtained complexes are

Chitosan-supported CuI-catalyzed cascade reaction of 2-halobenzoic acids and amidines for the synthesis of quinazolinones

• Xuhong Zhao,
• Weishuang Li,
• Mengli Yang,
• Bojie Li,
• Yaoyao Zhang,
• Lizhen Huang and
• Lei Zhu

Beilstein J. Org. Chem. 2025, 21, 839–844, doi:10.3762/bjoc.21.67

• ]. Furthermore, dicopper(I) complexes can also be used as an effective catalyst in Ullmann-type N-arylation/cyclization of 2-bromobenzoic acids with amidines, providing the corresponding quinazolinones in good yields [15]. Despite the high efficiency of the above-mentioned copper catalysts in the synthesis of

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• interactions also contribute to the stabilization of the ligand–iNOS complexes. In particular, 4-(1-methylamino)ethylidene-5-phenyl-1-(3-nitrophenyl)pyrrolidine-2,3-dione (5e) exhibited the strongest binding affinity (−9.51 kcal/mol) and demonstrated significant inhibitory activity against nitric oxide (NO

• π–π stacking is observed in the crystal packing of the complexes, but only C–H···π interactions are present. Two C–H···O hydrogen bonds complete the interactions stabilizing the crystal packing (Figure S1 and Table S2 in Supporting Information File 1). Inhibitory activity of NO production It is

• , Trp194, Gly202, Pro350, Phe369, and Tyr489, further contributing to the stabilization of the ligand–protein complexes. More importantly, the occurrence of an electron-withdrawing group, nitro group (NO2), on the aromatic ring linked to the 1-position of the pyrrolidine-2,3-dione core may help compound 5e

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• applications of calcium complexes with axially chiral BINOL phosphate ligands have been reported in recent years [28][32][33][34][35][36][37][38], as well as complexes with other chiral phosphoric acid ligands [39]. Since then, other main group metal complexes with BINOL phosphate ligands have been discovered

• ]. As observed earlier [53], cis/trans preferences in octahedral calcium complexes are influenced by small changes in sterics. Further details on the structure of 4 can be found in Supporting Information File 1. Complex 4 appeared to be a well-defined achiral model system for the catalyst combination

• , resulting in detachment of the cyanide carbon from the calcium atom to yield an isocyanide complex 9 [55], in which the preferred side of attack on the imine carbon of the hydrazone is already predetermined (i.e., from either Re or Si face). Notably, in both complexes formed from E- and Z-hydrazone, an

Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion

• Leon M. Friedrich and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57

• simulation (MD) [54] over 10 ns to determine the relative stability of the complexes (Supporting Information File 1, Figure S17 and Figure S18). The most stable receptor–ligand complexes so obtained were then submitted to a MM-GBSA calculation to deliver IFD binding energies (Table 3 and Supporting

• Information File 1, Table S25). Also the binding energies obtained with IFD for 6αMan 4 and 3αMan 5 are in accordance with the experimental data as they predict correctly that the ligand–FimH complexes formed with the E isomers of 4 and 5 are more stable than the complexes formed with the respective Z isomers

• . These differences correspond to the structures of the various ligand–FimH complexes (Figure 4A and B), however, it is difficult to substantiate the measured binding differences in detail. For example, it is not apparent that secondary interactions performed by the scaffold mannoside portion in the

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• with an electrophilic handle for the covalent attachment of the surrogate to the RNA. The resulting irreversibly tethered dye–RNA complexes have opened up new avenues for RNA imaging in live cells. Here, we report the syntheses of such modified HBC530 ((4-((2-hydroxyethyl)(methyl)amino)benzylidene

Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

• ][22][23][24][25][26]. Within these families of macrocyclic hosts, CB[n] molecular containers have proven particularly versatile because they form high affinity CB[n]–guest complexes in aqueous solution that are responsive to various stimuli (e.g., photochemical, electrochemical, chemical) [27][28][29

• sidewalls and the ureidyl π-systems. The small changes in chemical shift for the methonium group suggests it is located near the ureidyl C=O portals and not inside the magnetically shielding cavity. Related complexation-induced changes in chemical shift are observed for the other C1·guest complexes (Figure

•  4b), we observe separate resonances for free Me6PXDA and complexed C1·Me6PXDA which means that the rate of guest exchange is slow on the chemical shift timescale. Slow kinetics of guest exchange is commonly observed for tight host·guest complexes. In contrast, the kinetics of guest exchange are in

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• pathways are heavily time-consuming and synthetically challenging. In this context, chiral Ni(II) complexes can be powerful tools to obtain tailor‑made non‑canonical amino acids. In this work, we wanted to take advantage of this strategy and extend the range of this method to include additional fluorinated

• diastereomerically pure γ‑branched fluorinated amino acids. This work further underlines the importance of chiral Ni(II) complexes in the synthesis of fluorinated amino acids. Keywords: chiral nickel complexes; fluorinated amino acids; gram-scale amino acid synthesis; stereoselective synthesis; Introduction Non

• chiral nickel complexes. In recent years, the Soloshonok working group demonstrated the synthesis of non‑natural amino acids using the corresponding chiral Ni(II) complex [7]. In addition to the high enantiomeric purity of the corresponding products, the scale of the reaction, which extends into the

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• electronegativity, reaching 1.648 Å in the reactive alkoxytrialkyl complex D and 1.659 Å in the tetraalkyl "ate" complex E. The B–C bond lengths in amido- and alkyl-substituted boronic ester complexes B and C fell between these extremes, suggesting an intermediate level of activation. These findings prompted

• including s-BuLi, n-BuLi, and PhLi. The optimized protocol, employing CuCN as a catalyst, enabled efficient coupling between t-BuLi-activated complexes 10 and allylic halides 11, furnishing products 12 with complete retention of stereochemistry and high yields (Scheme 7). The method's versatility and

• boronate complexes and correlation with reactivity. Copper-catalyzed stereospecific allylic alkylation of secondary alkylboronic esters via tert-butyllithium activation. Copper-catalyzed stereospecific allylic alkylation of chiral tertiary alkylboronic esters via adamantyllithium activation. DFT-calculated

Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• H-ʟ-Trp-OH is also considerably higher than the values observed for the complexes of previously reported crown ether-type receptors with zwitterionic amino acids in water [22]. The affinity of 1 towards leucine, bearing a hydrophobic side chain, is over 4 times lower than towards tryptophan (entry 2

• tryptophan and Trp-containing peptides by 1 we performed NMR measurements on the 1:1 host–guest complexes in D2O. Upon binding of tryptophan by 1 a significant upfield shift of the aromatic protons and a slightly smaller shift, also upfield, of the α and β-Trp protons was observed (Figure 3). The aromatic

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• used to achieve higher yields [27]. Even in the absence of a transition-metal-based photosensitizer, a recent study showed that perfluoroalkylation using perfluoroalkyl iodides (RFI) could be carried out by activation of the RF–I bonds by formation of electron donor–electron acceptor complexes with an

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• an electrophilic handle for the covalent attachment of the ligand to the RNA. The simplicity of the underlying design of irreversibly bound ligand–RNA complexes has provided a new impetus in the fields of covalent RNA labeling and RNA drugging. Here, we present short and robust synthetic routes for

• , DPQ1) and haloalkyl-modified preQ1 and DPQ1. B) The ligand classes of XcnpreQ1 and XcnDPQ1 allow specific formation of covalent small molecule–RNA complexes as has been recently demonstrated (see ref. [4]). Electrophile (E). Three-step syntheses of preQ1 (1) and DPQ1 (2). For the synthesis of m6preQ1

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

• observed in dilute solutions because of the formation of aggregates perturbing electronic transitions [51][52][53]. Moreover, at high concentrations, the formation of electron donor–acceptor (EDA) complexes [54] or exciplexes is expected to be favored, and the effect of mechanical forces on these is worth

• zinc cations to align 1.1 through the formation of hydrogen-bonded coordination complexes. Thus, when a single crystal of the [Zn(bpe)2(H2O)4](NO3)2·8/3H2O·2/3bpe complex was exposed to UV irradiation (dark blue phosphor lamps, λ = 350 nm) for 25 h, only 46% conversion to 1.2 was observed via 1H NMR

• instead of 2 h in a row) proved beneficial to minimize heat accumulation resulting in product decomposition. Next, the authors proved the generality of mechanoluminescence by performing the sulfonylation of alkenes via EDA-complexes photochemistry (Scheme 12B). Thus, when a mixture of 1,1-diphenylethylene

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• sensitivity of in situ obtained complexes 9 and 10 with CN− to different cations. It appeared that the addition of an equivalent amount of Hg(ClO4)2 to an acetonitrile solution selectively and completely restores the initial absorption and fluorescence spectra (Scheme 3). Thus, the obtained compounds

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• diverse catalyst types and applications. The first section is dedicated to metal-based photocatalysts. Complexes involving metals such as osmium and ruthenium, have dominated red-light photoredox catalysis because of their ability to absorb low-energy photons and sustain redox cycles via stable excited

• states. In this section, the document highlights applications of these complexes in reactions like ring-closing metathesis and polymerization, where red light’s deeper penetration enhances yields and efficiency, particularly for large-scale reactions. The second section broadens the focus to explore

• photocatalysts, such as helical carbenium ions and advanced nitrobenzofuran derivatives for applications in phototherapy and controlled drug release, underscoring the potential of red-light photocatalysis in biomedicine. Review Red-light photocatalysis with metal-based complexes Metal-based complexes naturally

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

• this way, we were able to determine the HB donation ability of CF2H-containing compounds on a single scale. As shown in Figure 5, we determined dissociation constants (Kd) of n-Bu3PO···HB donor complexes, revealing several general trends. First, we found that CF2H groups attached to an extended

• , with other easily accessible parameters. We first calculated the Gibbs free energy of formation (ΔGcalc) of the HB complexes of HB donors with trimethylphosphine oxide (Me3PO), which models n-Bu3PO as a hydrogen bond acceptor, and compared these values with experimental data. We realized that such an

• –vis spectroscopic titrations with Reichardt’s dye, and (iii) 1H NMR titrations using n-Bu3PO as a reference HB acceptor. Our studies revealed that the 1H NMR titrations, although tedious, offered reliable binding affinity data for HB complexes involving neutral and cationic donor molecules. This

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• (Figure 15) [70]. In this catalytic system, catalytic amounts of Cu(sBOX) (L3) and Co(salen) complexes promote the formation of chiral nitriles 89 in the presence of PhSiH3 (88) as the hydride source and TMSCN (21) as the cyanide source via the effective sequential addition of a hydrogen atom and a CN

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• possible to exclude its action also as Lewis acid. Confirming this dual activity, it should be noted that copper triflate can rarely be replaced by other copper salts or complexes to obtain the same results. In general, catalyst switching does not work with copper triflate, thus supporting its unique

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• from certain plant species (Figure 1) [12]. The acenaphthylene-fused thiophene-based heteroarene 3 is another heterocyclic fluoranthene analogue, which was used as an organic semiconductor in transistors [13]. The synthesis and coordination complexes of the acenaphthylene-fused N-heterocyclic (NHC

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• photochemistry has introduced new ways of generating radicals like photoredox catalysis and via electron donor–acceptor (EDA) complexes [10][11][12][13]. These advances, coupled with modern electrochemical methods, chemical reactor engineering and light emitting diodes (LED), have eliminated the need for thermal

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• solutions [18]. Similarly, Burns and co-workers reported di- and tetra-urea picket porphyrins highlighting, the impact of buried solvent molecules, such as DMSO, on the selectivity, affinity, and stoichiometry of anion binding [19]. Iron complexes of tetra-urea picket porphyrins further demonstrate how

• functional versatility [44], and many of these resulting metal complexes are catalytically active [45][46][47]. These synthetic metalloporphyrins take inspiration from biological systems, such as hemes (iron complexes), chlorophylls (magnesium complexes), and vitamin B12 (cobalt complex). Contrary to

• macrocycles as electrocatalysts Development of efficient renewable technologies is a driving force in the efforts to achieve sustainability with the same or even increasing demands for energy worldwide. In this context, transition-metal complexes of tetraazamacrocycles (N4-macrocycle) such as porphyrins

Tailored charge-neutral self-assembled L₂Zn₂ container for taming oxalate

• David Ocklenburg and
• David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

• metallocontainers which are formed by metal-driven self-assembly have become especially popular to bind various kinds of anions since such systems offer easy to tune confinements. Usually, the utilized complexes are net positive which makes them ideal hosts for anions [56][57][58][59][60][61][62][63]. However, the

• be volatile to simplify complex purification. Second, the solubility of the neutral host complexes usually needs to be improved by the installation of solubility groups, which must be considered during ligand design. The biggest strength of metallocages and metallocontainers, whether they are

• coordinating or which can act as good chelating ligands [65]. The latter holds true for oxalate as shortest dicarboxylate anion which likely forms complexes with all sorts of metals [66][67]. In fact, oxalate’s ideal ligand character is one reason for the aforementioned diseases and this property poses a fatal

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• of allylic peroxidation 2, 4 and 5 were observed (Scheme 4) [24]. Similar transformations were reported later using CuCl as the catalyst [39]. Later, Gade with coauthors demonstrated the allylic peroxidation of cyclohexane with TBHP using the alkylperoxocobalt(III) complexes [Co(BPI)(OAc)(OO-t-Bu

• -t-Bu)2. Allylic peroxidation of 3-substituted prop-1-ene-1,3-diyldibenzenes 8 was performed with TBHP as the oxidant/peroxidation agent and with Cu2O as the catalyst [42] (Scheme 6). The proposed mechanism of peroxides 9 formation does not include peroxo–copper complexes and begins with the

• formation of peroxide 9. The enantioselective peroxidation of alkenes 10 with TBHP with the formation of the optically active products 11 was carried out in good yields and low ee by the use of in situ-generated chiral bisoxazoline–copper(I) complexes (Scheme 7) [43]. Studying the oxidation of α-pinene (12

Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides

• Baptiste Leroux,
• Alexis Beaufils,
• Federico Banchini,
• Olivier Jackowski,
• Alejandro Perez-Luna,
• Fabrice Chemla,
• Marc Presset and
• Erwan Le Gall

Beilstein J. Org. Chem. 2024, 20, 2834–2839, doi:10.3762/bjoc.20.239

• nucleophilic organozincate complexes (e.g., LiBuZnBrCl), which is a well-established process in THF [29][30]. Due to the hygroscopic character of LiCl and the necessity to determine the amount of organozinc by iodolysis [20] in order to adjust the stoichiometry of the reagents for the multicomponent coupling

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• , highly sensitive chemosensors via a facile synthetic route/method, we have explored three chelates for lanthanide ions (DO3A, 2,6-pyridinedicarboxylic acid and DO2A), resulting in complexes with different overall charges. Additionally we have explored two copper(II) binding groups (di(2-picolyl)amine and

• aqueous hydrogen sulfide and 100 ppb for gaseous hydrogen sulfide [16]. However, due to the limited aqueous solubility and ligand dissociation of this chemosensor, and to the weakly luminescent bis species at usable concentrations, we extended this work to the lanthanide–macrocycle binary complexes [Ln

• not exhibit any discernible increase in luminescence. As far as we are aware, there are only three reports of lanthanide-based probes for the detection of gaseous hydrogen sulfide. Two are the europium(III) complexes from our group ([Eu(triazole-DPA)3·Cu]3+ and [Eu(DO2A)(triazole-DPA)·Cu]+), which are