Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• concentration. As for the macrocycles discussed above, dual confinement/encapsulation [36] and the hydrophobic effect dominate the origin of catalytic rate enhancements [158][159]. To avoid product inhibition, model reactions that increase molecularity (A → B + C) or that generate weakly interacting or less

• catalysis [229]. Methods to study the structural detail of catalysis in frameworks remain limited, and crucial techniques like solution-phase NMR are rarely useful [22]. Enzyme encapsulation [230], and electro- and photocatalysis are known [228], and chiral and low symmetry MOFs are an exciting avenue

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

• , characterized by a concave shape with a central cavity [1]. Such structures hold significant potential for drug delivery applications as nanomotors, offering both encapsulation capability and controlled release functionalities [2][3]. Moreover, researchers have explored novel shapes utilizing PEG-PS copolymers

• holds profound implications for drug delivery and beyond. By tailoring vesicle morphology to specific requirements, researchers can optimize drug encapsulation, targeting, and release, advancing the efficacy and precision of therapeutic interventions. Continued exploration of these versatile materials

• stronger osmotic pressure within the vesicle, driving deformation into a stomatocyte shape. This novel morphology for polysarcosine-based polymers opens new avenues for utilizing fully biodegradable polymers as nanomotors, leveraging enzyme encapsulation techniques. Moreover, it was observed that a

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

• disassembly of the host structure. Guest-driven decomplexation events can also be utilized as detection method [65][68][69][70][71][72][73] but such processes are generally not desired for containers or cages because guest binding is anticipated to take place by encapsulation while the structure of the

• , only a few reports with the focus on host–guest binding studies exist in which classic cationic metal-driven self-assemblies seem to be capable of binding oxalate without suffering from its competitive nature [75][76][77][78][79]. Guest encapsulation was investigated with cationic metalla-rectangles as

• limiting solubility. a) Generally desired guest recognition by encapsulation of the analyte within self-assembled metal-based containers or cages (left reaction). Often observed challenge with very competitive anionic guests which tend to result in decomposition of the initial receptor structure (right

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

• immobilization strategies, including covalent bonding and encapsulation, cater to different polymer types. Soluble polymers enhance diffusion, while insoluble ones ensure stability and high loading capacities [42]. Silica is also widely applied due to its ease of functionalisation and thermal stability [43]. The

• catalytic species. These methods can be classified into four categories: covalent bonding, non-covalent interactions (physisorption), ionic bonding, and encapsulation. The catalysts are connected to the support via strong chemical bonds in covalent bonding. In non-covalent interactions, the catalysts are

• adsorbed onto the support surface through weaker intermolecular forces, such as van der Waals forces and hydrogen bonding. Ionic catalysts form ionic bonds or those that can be ionised under immobilisation conditions. Encapsulation involves physically trapping the catalyst within the pores or cavities of

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• the addition of tert-butyl isocyanide. On the other hand, the addition of tert-butyl isocyanide on the imine altered the orientation of adduct 19, suppressing the interaction with Ser105 (Scheme 8). Very recently, Tyagi et al. reported the double encapsulation of CALB and Pd(PPh3)4 within silica

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

Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

• Eiichi Kayahara,
• Yoshiyuki Mizuhata and
• Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

• function. After our first report on the selective encapsulation of C60 by [10]CPP (the number in the brackets is the number of paraphenylene units in the CPP) (Figure 1a) [22], the concave inner surface of CPPs was found to interact with a variety of molecules with convex surfaces through π–π interactions

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• depicted in Scheme 14, the 12-membered ring orifice of fullerene 51 was first enlarged by electrophilic addition of sulfur. After encapsulation of H2 molecule(s) (n = 1 or 2), four synthetic steps were required to reduce the hole size and ultimately obtain cage-closed compound (H2)n@54. In order to remove

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• the hole is closed restoring the original cage. Among the species that have been incarcerated with this procedure, we can find He, Ne, Ar, Kr, H2, N2, O2, HF, CO, CO2, H2O, H2O2, CH4, NH3, HCOH, HCCH, and CH3OH [26][27]. The encapsulation of atoms or small molecules inside the fullerene has been found

• larger orifices in C70 derivatives given that the larger cavity compared to its C60 counterpart can facilitate the encapsulation of multiple atoms and molecules [40][43][53][54]. To fulfil this objective, compound 2a was subjected to oxidative cleavage by exposing it to light in the presence of air

Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• , the interaction between the C60 surface and the walls of the armchair (10,10) CNT. The interaction or encapsulation energy of a fullerene inside the CNT, defined as Eencap = EFuller@CNT – EFuller – ECNT, amounts to −3.23 eV for C60 at our present computational settings (PBE/plane waves, see section

• similar systems with π–π interactions, as for example a “buckyball catcher” complex with C60 or the interlayer interaction between graphene sheets [16]. It is found to be significantly smaller than for C60@C240 [17], but larger than for C60@C540 and C60@C960 nanoonions [18]. The encapsulation energy of

• % of the total encapsulation energy. As a consequence of the effective π−π interactions, the larger the contact between the fullerene dimer surface and the CNT wall the larger the encapsulation energy. This significant interaction is also apparent from an inspection of the electronic structure of the

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• ). As expected, previous aromatic micelle (AA)n (1.0 mM based on AA) featuring multiple ionic side-chains showed a significantly higher ZP of 48.9 mV. The ZP of (PA-OCH3)n largely increased upon encapsulation of C60 (46.7 mV) and s-CNT (43.2 mV), due to the stabilization of the host–guest composites

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• transfer, followed by bimolecular nucleophilic substitution (SN2) reaction [8]. Endohedral metallofullerenes, wherein one or more metal atoms are encapsulated inside a fullerene cage, have garnered research interest [12][13][14][15]. The encapsulation of metal atoms can result in electron transfer from the

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• should focus on understanding degradation mechanisms, developing effective device encapsulation strategies, and ensuring environmental compatibility to guarantee sustained performance and viability in commercial applications. Additionally, scalability and cost-effective manufacturing processes are key

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• and a thermal evaporation rate of 0.2–0.3 Å s−1 for MgF2, HATCN, NPB, TCTA, TPECNz, and TPBi, 0.05–0.1 Å s−1 for LiF, and about 1 Å s−1 for Al layer. The thickness of each layer was monitored by a quartz oscillator thickness sensor. All devices were measured without encapsulation under an ambient

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• [23][88][90]. Several studies have focused on developing novel crown ether-appended porphyrins with tailored caps, enabling efficient encapsulation of guest molecules through host–guest interactions [47][81][112]. They have shown promise as heme models and multitopic receptors, exhibiting selective

Cyclodextrins as building blocks for new materials

• Miriana Kfoury and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2023, 19, 889–891, doi:10.3762/bjoc.19.66

• , and catalysis [2][5][12]. Molecular encapsulation is not the only application area for these macrocyclic components at present. CDs are versatile molecules. Their 3D structure makes them exceptional building blocks for the design of innovative supramolecular architectures due to the differential

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• % [17]. Other complexes between CDs and various vegetable oils have been obtained and characterized. Soybean oil was combined with α-CD for obtaining a stable dry emulsion, which implied the partial molecular encapsulation of the soybean oil triglycerides. This emulsion was prepared in order to modulate

• cannabinus L.) seed oil or “Persian lilac” (Melia azedarach L.) seed oil. The oils were complexed by spray drying using β-CD/gum arabic/sodium caseinate or a β-CD polymer, respectively [22][23]. However, there are less studies on the CD encapsulation of non-volatile vegetable oils in comparison with

• discrimination of such ternary complexes on the basis of FTIR. The evaluation of the encapsulation competitiveness of such multicomponent mixtures is very challenging (highly hydrophobic FA triglycerides, mono- and diglycerides, free FAs, as well as more hydrophilic flavonoid glycoside, namely hesperidin

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• using polymeric nanoparticles for anticancer drug delivery have not been developed yet. Previous data showed encapsulation in non-ionic uncoated or coated cyclodextrin (CD) nanoparticles enhanced the CPT stability and GI absorption [9][11], and compared to PCL and PLGA nanoparticles, CD nanoparticles

• the ability to self-assemble into NPs amenable for encapsulation of an array of therapeutics (from small molecule drugs to nucleic acids) [19]. Moreover, their dense ammonium functional display furnishes their NPs with an overall positive charge and large buffering capabilities [19] at physiological

• encapsulation into nanoparticles, is an approach worth investigating. Conclusion Oral cancer therapy is still a milestone, attracting researchers' efforts, especially in cancers with high mortality such as CRC. Any progress in this area would be very promising. In this context, oral chemotherapy formulations in

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• 1H NMR spectroscopy. Subsequent measurements of the aqueous solubilities of the four complexes confirmed significant solubility improvements effected by encapsulation of the steroids within the CDs, yielding solubility enhancement factors for BES and PRO in the approximate range 5–20. Keywords

• accurate host–guest stoichiometric ratios obtained from 1H NMR analyses with the respective crystal water contents derived from thermogravimetric analyses. The aqueous solubilities of the two APIs, 17β-estradiol and progesterone, were found to be significantly enhanced via their encapsulation by β-CD and γ

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• concentration of less than 1% within four hours, and water-soluble monomers. In addition, the integration of this setup into an inline synthesis step starting from block copolymer solutions, and rhodamine encapsulation produced micelles without affecting the particle size is also demonstrated. The growing

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• ; imine; kinetics; pro-fragrance; Schiff base; Introduction The fragrance and flavor industry is one of the most intensively developing sectors of the chemical industry. Encapsulation techniques are widely used in both food and cosmetic industries to control the delivery of the encapsulated guest

• present an advantage compared to simple encapsulation and to other substrates as they will not only ensure very low volatility of the obtained pro-fragrance but also be able to encapsulate the guest after the cleavage of the covalent bond, leading to a two-in-one system. Indeed, encapsulation in CDs is

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

• , organic host molecules such as cyclodextrin [50], pillararenes, and cucurbiturils [51] have been developed in the last decades. Although, these exhibit excellent host–guest encapsulation properties with a variety of organic molecules, there are major drawbacks associated with them: variation of the shape

• demonstrated by Reek and co-workers by using a previously reported heteroleptic bisporphyrin cage [76]. The tetragonal prismatic nanocage 47 consisted of two zinc-porphyrin units along the two tetragonal faces (Figure 11), which allowed encapsulation of the chiral phosphoramidite 48 as a precursor for the

Synthesis of a new water-soluble hexacarboxylated tribenzotriquinacene derivative and its competitive host–guest interaction for drug delivery

• Man-Ping Li,
• Nan Yang and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2022, 18, 539–548, doi:10.3762/bjoc.18.56

• larger cavity as compared to TBTQ-C6 due to the introduction of triazole rings. Two anticancer drug molecules, dimethyl viologen (MV) with a smaller size and DOX with a larger size, were selected as model anticancer agents for encapsulation by TBTQ-CB6 to form the host–guest complexes of TBTQ-CB6MV and

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

• Hao Guo,
• Yu-Fei Ao,
• De-Xian Wang and
• Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

• was commonly introduced through in-situ, noncovalent inclusion/encapsulation in the cavity or by covalent, post-functionalization of the macrocyclic scaffold. The encapsulated catalytic group could occupy the space for substrate entering, or has a risk to be squeezed out of the cavity under complex

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• compared to many other strong Brønsted or Lewis acids. Keywords: cationic intermediates; encapsulation; organocatalysis; resorcin[4]arene hexamer; supramolecular catalysis; Introduction In enzymatic catalysis, the substrate is selected matching the size, shape and specific functional groups present in