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

• controlled (cf. Supporting Information File 1, Figures S13–S16). The testing results are illustrated in Figure 3. All photoswitches comprising an α-ᴅ-mannopyranose ligand bound to an azobenzene unit (1, 2, 4, and 5) show a stronger inhibitory potency than MeMan. This can be explained by, i.a., π–π

• -interactions of the aromatic azobenzene portion with the so-called tyrosine gate at the entrance of the FimH carbohydrate binding domain constituted by Tyr48 and Tyr137 [44]. In case of the glycoazobenzene antennas 6αMan 4 and 3αMan 5, it is apparent that the inhibitory potency of the individual glycoconjugate

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

• , two aromatic o-xylylene walls, and four sulfonates as solubilizing ionic groups. In accord with these structural features, M1 binds a variety of hydrophobic and cationic guest molecules by the hydrophobic effect, π–π interactions, and electrostatic (ion–dipole and ion–ion) interactions. Although

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

• Information File 1). These observations suggest that receptor 1 binds selectively to the Trp residues in the studied tripeptides and the binding occurs predominantly through π–π interactions. This conclusion is supported by the considerably lower affinity of 1 to peptide 8, lacking a Trp residue, and by the

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

• , the size and conformational flexibility of the five BnF groups resulted in significant disruption of CORA–CORA π–π interactions due to the greater CORA–CORA bowl-to-bowl distances relative to the less bulky C5-CORA(CF3)5 analogue [18][19]. However, corannulene derivatives are only weakly fluorescent

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

• secondary amine 57. They have hypothesized that the organocatalytic activity of the aggregates is based on two types of interactions, i.e., electrostatic interactions of α,β-unsaturated iminium cations derived from cinnamaldehyde and the cyclic secondary amine with anionic sulfonate groups and π–π

• interactions between phenyl groups and cyclopentadiene. Due to the presence of both types of moieties on the aggregate surface, the two reacting species can get into proximity and form the desired product (Figure 10b). Later, an analogous system was used for catalysis of an asymmetrical Diels–Alder reaction

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• ][16][17], high electron affinity, excellent self-assembling properties [18][19][20], and thermal and photochemical stabilities [21]. The excellent charge carrier mobility of PDIs has been explained by the intermolecular π–π interactions with an interplanar distance (3.3–3.5 Å) [22][23][24][25] that

• ) exhibit the strongest π–π interactions since the distance between two adjacent molecules is shorter and less steric repulsion is observed. This was reflected by the highest hole mobility of the derivatives with n-hexyl chains (3.15 × 10−4 cm2 V−1 s−1), compared to derivatives with n-octyl chains (1.76

• × 10−4 cm2 V−1 s−1) and 2-ethylhexyl chains (4.93 × 10−5 cm2 V−1 s−1). The stronger π–π interactions led to a higher power conversion efficiency (PCE) as a result of the higher short-circuit current density (Jsc), due to films with higher crystallinity providing a smoother pathway to charge carriers to

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• porphyrins Nonplanar porphyrins are known to form supramolecular assemblies [6], either through hydrogen-bonding networks or through π–π interactions. Examples of this can be seen in the trapping of Keggin-type heteropolyoxometalate (POM) through nonplanar Mo(V)–porphyrin complexes [58], or porphyrin

• nanotubes/nanochannels by intermolecular π–π interactions of the peripheral phenyl groups [59]. Additionally nonplanar supramolecular assemblies have found use in anion capture [12][15], and sensing [60], making the synthesis of these structures desirable from a supramolecular standpoint. Two especially

Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions

• Hayato Takagi,
• Çetin Çelik,
• Ryosuke Fukuda,
• Qi Guo,
• Tomohiro Higashino,
• Hiroshi Imahori,
• Yoko Yamakoshi and
• Tatsuya Murakami

Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231

• present study for controlling both the location and photodynamic actions of a cationic derivative of C60 (catC60), a simple model compound of the triad molecules, in a membrane via π–π interactions with 1-pyrenebutyric acid (PyBA). (d–f) Chemical structures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• –N1 is 160°/164°, here and further, two data sets are given, taking into account the pyridine cycle disorder). In the crystal of 5, two molecules form pairs due to the π–π interactions between pyridine cycles (the Cg···Cg distance between centroids is 3.855(4) and 3.891(4) Å; the angle between the

• -bonds and π–π interactions are shown as dotted lines). The interactions in pair of independent molecules A and B of 6 in crystal 6·0.5CH3CN (the H-bonds are shown as dotted lines). Fragment of the pack of catechol 8 in crystal (the H-bonds and π–π interactions are shown as dotted lines). The CV curve of

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

• give the desired product 99 after 72 h returning hemiaminal (Scheme 21). Alkyl acetals, such as cyclohexyl carboxaldehyde acetal reacted sluggishly with low yield and selectivity (<10% yield, 43–50% ee), possibly due to their inability to participate in π–π interactions. In general, the π-stacking

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

• physical organic chemistry with data-driven analysis techniques, in particular MLR, to gain a greater understanding of the enantioselectivity-determining steps for a C–N coupling catalysed by CPA derivatives (Figure 15A) [143]. Based on their findings that π–π interactions between the catalyst’s triazole

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

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• electron density, which facilitates a π–π interactions with the aryl iodide system and ultimately results in the production of an electron donor–acceptor (EDA) complex 21. Photoexcitation of this EDA complex furnishes an aryl iodide radical anion and a radical cation complex 22. Then, the elimination of

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• suggest π–π interactions in the latter complex. Their difference in Ebind shown in Figure 6a can be interpreted by that in these interactions. In addition, their difference in conformational flexibility supports the wider favorable diameter range of 1b than 1a. Conclusion A cyclic host molecule (Cu

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• perylenebisimide (PBI) components connected laterally through H-bonding and self-assembled orthogonally through π–π interactions [13]. Mixtures of PBI and OPV successfully exhibited ambipolar charge transport depending on processing conditions as a result of the co-assembled morphology. Our group utilized a

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• ), π–π interactions between the alkyne groups can be observed. Moreover, the alkyne phenyl group interacts mainly with molecules between different layers in the vertical direction, while the phenyl group interacts vertically and horizontally with different molecules. The two-fold Suzuki reaction was

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• °, fold angle 4.38°). The molecular packing of compound 3b was characterized by the presence of numerous π–π interactions (Figure 4). Intermolecular interactions in the benzo[b]thiophene fragment (red planes in Figure 4) were characterized by the following parameters: plane centroid–plane centroid

• packing of compound 3b, showing π–π interactions in the crystalline state. The main centroid–centroid distances are indicated in Å. Absorption spectra of compound 2a in acetonitrile before (1) and after (2) the addition of Fe2+ (c2a 5.0 × 10−5 mol·L−1, cFe2+ 1.0 × 10−4 mol·L−1). Inset: fluorescence

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

• affect the recognition unit, pH-switchable molecular tweezers with acridinium functional units have been recently reported by de Rouville et al. [29]. The acridinium moiety is a planar electron-poor aromatic system that can form π–π interactions with electron-rich molecules [30]. The particularity of

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

• 2, the observed interlayer distances indicate the importance of the π–π interactions in complex formation. In contrast, complex 3 has fewer π–π interactions between [10]CPP and [5]CPP2+ than complexes 1 and 2 have. However, several CH–π interactions are observed, as indicated by an orange dotted

• in the range of 0.35–0.39 nm (Figure 7b), illustrating the importance of π–π interactions. The Hirshfeld surface of the [5]CPP guest in the complex has a cylindrical structure and is confined to the interior of [10]CPP (Figure 7c) [45][46]. In the de mapping (Figure 7d), which shows the distance

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• the phthalimidyl anion within the chiral pocket of the phosphate catalyst to form complex 55, before enantioselective addition to the iminium ion affords product 56. NHPI esters can also engage in π–π interactions with electron-rich species to generate charge-transfer complexes that can absorb light

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

• Computational methods). This significant amount of energy, which could be overestimated, comes from the π–π interactions between the C60 surface and the CNT wall and is modelled in a first approximation using Grimme’s corrections to the dispersion energy [16]. This interaction energy is comparable to those in

• 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

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• compound 29 is perpendicular with respect to the herringbone pattern and the related structures (see Figure 10, bottom). Compound 25 packs with an intramolecular distance of 3.41 Å between the planes of the π-systems. Neither compound 26 nor 29 shows π–π interactions in the crystal packing. The large

• bulkiness of the TIPS groups along with the tert-butyl groups in compound 26 prevent these interactions, while for compound 29, the lack of π–π interactions can be ascribed to the methylene bridges as the hydrogens along with the tert-butyl groups prevent good overlap of the π-systems. Table 3 lists the

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• (Figure 2) were designed to be obtained from precursors containing two 1,4-dioxobenzene fragments required to facilitate π–π interactions with the pyridine unit in the axle (compound 6 in Scheme 1) and confer stability to the supramolecular complex necessary for the formation of [2]rotaxanes. For the

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• from strong π–π interactions [7][21][22][23][24]. In this work, we investigated a perylene and a pyrene-based columnar liquid crystal in hole-only and electron-only devices to compare their charge carriying properties. The molecular organization and photophysical performances are coherent with the

• solution, the 6.90 ns lifetime in the film is attributed to monomeric emission. The shortest lifetime of 0.90 ns can be related to the emission of aggregated species driven by π–π interactions [36], contributing to almost 20% of the total emission of 1. The longer lifetime of 2 in film (3.84 ns) can be

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• supramolecular organization of the N-acylhydrazones was also studied through their Hirshfeld surfaces, in which π–π interactions play an important role. When the normalized distance between a molecule and the closest neighbors are plotted (Figures S2A and S2C, and S3A and S3C in Supporting Information File 1