Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• = 2.24 nm could be attributed to the longer molecular axis of DA11 in dimer form, while that at d = 0.36 nm originated from π–π stacking of the DASA motif. Consistently, diffraction from the longer molecular axis of DA10 in dimer form was shorter (d = 2.19 nm) than that of DA11, revealing the subtle

• π–π stacking of the DASA motifs. However, no significant unidirectional alignment was observed in WAXD and SEM images of DA7 and DA6 macroscopic soft scaffolds (Figure S11a and S11c as well as S12a and S12c, Supporting Information File 1, respectively). Electron microscopy and WAXD revealed that a

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

• radical cation 81 and Mes–Acr because of the favorable π–π stacking. Ethyl vinyl ether, which is the most nucleophilic molecule in the reaction, combined with radical cation 81 to form the oxonium radical 82, which could proceed in two directions: 1) β-elimination, yielding radical 83 and 2) photoinduced

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• -butyl groups, which disrupted the π–π stacking between the fullerene cages. The slight difference in sublimation temperature between t-Bu-FIDO and t-Bu-FIDS might be due to the slightly higher electron density of the sulfur atom compared with the oxygen atom. Additionally, data on the degradation

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• ], photonics [2], and diagnostics [3]. Their popularity stems from their structural rigidity, potential conjugation with the remaining structure, and the capability to form additional π–π-stacking interactions. Dihalides, in particular, are highly preferred in such applications, enabling the formation of

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

• favorable π–π stacking in the solid state. The 5% weight loss values range from 232 °C to 353 °C. Compounds with larger π-surfaces exhibited greater thermal stability (353 °C for 3a, 304 °C for 4a, 312 °C for 6a) while others displayed 5% weight loss values under 250 °C (232 °C for 1a, 244 °C for 2a and 238

• packing of 2b is expected to be favorable for charge mobility within stacked arrangements [36][37]. Additionally, the intermolecular π–π stacking distance is reduced to 3.285 Å in the staggered form (Figure 6f and 6g), 0.27 Å shorter than its non-hydrogen bonding dicyano comparator 2a. The single-crystal

Spin and charge interactions between nanographene host and ferrocene

• Akira Suzuki,
• Yuya Miyake,
• Ryoga Shibata and
• Kazuyuki Takai

Beilstein J. Org. Chem. 2024, 20, 1011–1019, doi:10.3762/bjoc.20.89

• material design should be important in this viewpoint, especially in choosing appropriate guest molecules. Since π electrons extend to in-plane directions in nanographene, a guest molecule with an aromatic ring is promising for significant interaction with the nanographene host through π–π stacking

• mesoporous silica (MCM-41) [18]. So, ferrocene is expected to exhibit strong host–guest interactions with a nanographene host through π–π stacking. Regarding ferrocene as a guest molecule for nanocarbon hosts, carbon nanotubes (CNTs) have been used to accommodate guest ferrocene molecules, where the amount

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

• reported. The adsorption of PASE has been considered to mainly come from the pyrene fragment, which forms π–π stacking on these graphitic carbon materials [6][7][8]. The sensitivity of the oscillator-based sensor depends on the structure of the linker molecule. Therefore, understanding the adsorption

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

• the phenanthroline unit was also involved in a π–π-stacking interaction (blue plane–green plane in Figure 4), with the plane centroid–plane centroid distance being 3.6998(8) Å (plane shift 1.4919(17) Å, twist and fold angles 1.54° and 1.92°, respectively). Cation-induced transformations of the

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

• quenched when the tweezers are closed by the addition of a Zn2+ cation because of intramolecular π–π stacking interactions between the chromophores. The system can be reopened and its luminescence properties restored by introducing tris(2-aminoethyl)amine (TREN), which has a better affinity for Zn2+ and

• square planar conformation giving an almost parallel arrangement of the aryl arms. This creates a cavity able to complex small coordinating guests that interact with the copper as ligands and also with the arms through π–π stacking. This system is selective towards flat aromatic guests and towards

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

• devices [1][2][3][4][5][6][7][8]. In this regard, the planar character of most (non-substituted) π-CPCs represents a challenge, as it results in very low solubility in common organic solvents due to favorable intermolecular π–π stacking interactions. This inherently hampers the purification of the target

• conformation of the thiepine ring, thus weakening the π–π stacking intermolecular interactions. Finally, solid-state S-extrusion could be triggered in a controlled way upon thermal activation of 21, as observed in thermogravimetric analysis, with the loss of sulfur detected at 223 °C to yield the planar S

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• melting point of indigo is bifurcated intra- and intermolecular hydrogen bonding [11], and face-to-face π–π stacking of parallel aromatic rings (Figure 2) [12]. Single crystal X-ray diffraction analysis showed that the indigo molecule is almost planar and exists in the E-conformation. The central C=C bond

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• arising from hydrogen bonding and π–π stacking interactions. In contrast, when 75 is incorporated into a nanocomposite with polystyrene serving as the matrix, luminescent properties are observed [141]. Photoinduced intramolecular energy and electron transfer Exploiting the electron-accepting property of

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

• ) [30][31], metal-ion template (coordination bonds [22][32], ion-dipol [16], donor–acceptor (charge transfer, π–π stacking) [30][33], and oligoamide macrocycle-hydrogen acceptors (hydrogen bonding) [20][34]. In active-metal template methods (Figure 1) the metal ion acts both as template and catalyst for

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

• crystallinity and optical absorption but a shorter π–π stacking distance. OSC devices based on Qx23 and Qx25 achieved the highest PCE (10.67 and 12.19%, respectively) compared to Qx22 and Qx24 (6.94 and 8.01%, respectively) [35]. Xiao and fellows studied the impact of side chains on molecular packing and

• section "Quinoxalines as polymer acceptors" also fabricated OFETs using QxCN-based polymer acceptors and demonstrated unipolar n-type characteristics with moderate OFET mobilities. The well-ordered structures with tight π–π stacking in Qx2 and Qx3 contributed to electron mobilities greater than 1.0 × 10−4

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• the amine nitrogen of the guest molecule. In addition to hydrogen bonding, other interactions such as π–π stacking and electrostatic interactions also play a role in the complexation process. These interactions can be modulated by changing the pH, solvent, and temperature of the solution. The binding

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• revealed that 4BGIPN molecules experience face to face intermolecular π–π stacking interactions between the benzoguanidine moieties similar to 4CzIPN (reported by Etherington et al., [12]). The average interplanar distance for close neighbor benzoguanidine moieties in 4BGIPN is 3.322(3) Å, which is

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• -Friedel–Crafts reaction between indole 4 and α-iminophosphonate 35. The reaction functionalized the C3 position of the heterocyclic ring with an α-aminophosphonate group. Chiral phosphoric acid P12 was the stereoselectivity inducer in the products 36 as explained by π–π stacking and H-bonding interactions

• resonance-assisted accumulation of negative charge on C6 enabled the carbon to add to the electrophile selectively from the Re face of the imine plane because of substrate–catalyst H-bonding interactions (see transition state 51). Beside multiple noncovalent interactions, π–π stacking between the

• substitutents. Excellent dia- and enantioselective synthesis of the products were caused by a chiral environment induced in the transition state through a dual H-bonding interaction between both the substrates and catalyst. In addition, π–π stacking between the aromatic moieties in both reagents brought more

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• modelling combined with spectrophotometric experiments revealed that in neutral and acidic buffered water solutions conjugates predominantly exist in intramolecularly stacked conformations because of the π–π stacking interaction between pyrene and phenanthridine moieties. The investigated systems exhibited

• + and Phen-Py-2+, where π–π stacking contacts are further promoted by the favorable cation–π interactions. Phenanthridine–pyrene conjugate Phen-Py-1 showed excimer fluorescence that was red shifted compared to the emission of a single phenanthridine or pyrene chromophore. This excimer fluorescence was

Asymmetric synthesis of a stereopentade fragment toward latrunculins

• Benjamin Joyeux,
• Antoine Gamet,
• Nicolas Casaretto and
• Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 428–433, doi:10.3762/bjoc.19.32

• %). This compound results from the transposition of the para-nitrobenzoyl (PNBz) group onto the 13-OH, which could be favoured by the steric hindrance of C-15 and a possible π–π stacking with the OPMB group. These PNBz esters were readily hydrolyzed to furnished diol 24 in 97% yield. The oxydation of the

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• other related molecules. Based on the collected data, the porphyrin complex 160 was found to show J-type aggregation in both polar and nonpolar solvents. In polar solvents, aggregation was induced by van der Waals interactions between H-cardanol moieties, while π–π stacking interactions between

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• electrocatalytic efficiency (TON up to 2000) was achieved using the TEMPO derivative non-covalently immobilized on the surface of a carbon cloth anode due to the π–π stacking interaction between the pyrene fragment of the catalyst and the electrode surface [103] (Scheme 15). However, this method is not compatible

• electrochemical oxidation of primary alcohols and aldehydes to carboxylic acids. Electrocatalytic oxidation of benzylic alcohols by a TEMPO derivative immobilized on a graphite anode by π–π stacking interactions. Electrochemical oxidation of carbamates of cyclic amines to lactams and oxidative cyanation of amines

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• metal-based emitters in organic light-emitting diode (OLED) devices [18]. Nevertheless, many TADF emitters suffer from quenching of the emission due to the aggregation-caused quenching effect [19][20]. The strong π–π-stacking interactions in the solid or aggregated state may lead to emission quenching

• . Therefore, an appropriate molecular design to suppress π–π stacking should help to obtain a strong emission in solution as well as in the solid state. Solid-state organic emitters with reversible fluorescence switching are emerging for the sensing of pollutant acid vapor [21][22][23]. However, quickly

• the native THF solution. Another factor that may have been responsible for this were the π–π-stacking interactions in the aggregated or solid phase of BPy-pTC as compared to twisted BPy-p3C [36]. To determine the effect of aggregation on the spin-flipping process (indicated by kRISC) from the low

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

• aromatic walls that offer van-der-Waals and π–π stacking interactions in order to compensate for the absence of a strong electrostatic interaction. These non-covalent/ionic interactions play an important role in encapsulating aromatic organic molecules, especially in aqueous medium. Along this rationale

• molecules through π–π stacking with the hydrophobic aromatic wall of the host. Finally, the boat was investigated as a catalyst for the Knoevenagel condensation reaction (Figure 2) of a series of aromatic aldehydes with 1,3-dimethylbarbituric acid and Meldrum’s acid in aqueous media. One of the primary

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• /ΦEtOH) was smaller than 1.0. These results indicated that aggregation was induced by π–π stacking interaction of the planar structures of compounds 3a and 3b in aqueous solution and that their excited states decayed by non-radiative pathways, resulting in ACQ. In contrast, the fluorescence intensities