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

• mechanically interlocking cyclic molecules are reported not to be removed with washing [11][22][23][24]. In addition, these Raman signals of 1b shift to higher frequencies at e- and i-SWNTs, similarly to our previous report [11], probably due to the structural change of Cu-nanobrackets 1b, or the energy

• binding energy between SWNTs and the host molecules is calculated by the GFN2-xTB method, because the number of atoms is too large to use DFT methods. The binding energy Ebind is calculated by the following equation: The Ehost, ESWNTs and Ecomplex are the electronic energies of the host molecules, SWNTs

• p-SWNTs. Red and black characters indicate metallic and semiconducting SWNTs, respectively. (a, b) Enriched (n,m)-SWNTs are shown in orange. (a) Binding energy between SWNTs of various (n,m)-structures with Cu-nanobrackets 1a and 1b; GFN2-xTB-optimized structures of (b) 1a@(9,4)-SWNT and (c) 1b

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

• transporters [9][10]. Organic photovoltaic (OPV) and perovskite solar cell (PSC) technologies have proven to be promising candidates for the sustainable use of solar energy, with power conversion efficiency (PCE) improving to 17% for OPVs and over 25% for PSCs in just a few years [11]. Functionalized fullerene

• derivatives with an emphasis on tuning solubility and energy levels. Meanwhile, less attention has been devoted to improving the thermal stability of fullerene derivatives. One well-known example is [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which is recognized for its excellent solubility in solution

• bond length may have caused the higher reactivity and lower degradation temperature of t-Bu-FIDS compared with t-Bu-FIDO. Electron-accepting ability is one of the most important properties for fullerene derivatives, and it is typically described in terms of the energy level of the lowest unoccupied

Synthesis and optical properties of bis- and tris-alkynyl-2-trifluoromethylquinolines

• Stefan Jopp,
• Franziska Spruner von Mertz,
• Peter Ehlers,
• Alexander Villinger and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1246–1255, doi:10.3762/bjoc.20.107

• different fine structures. However, TD-DFT calculations using the long-range correlated CAM-B3LYP/6-311G(d,p) level of theory reveal that the lowest energy band for all three derivatives 6a, 9a and 12a originate mainly from a HOMO→LUMO transition with some admixture of HOMO−1→LUMO+1 and HOMO−1→LUMO

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• catalyst in the sulfonylation/arylation of styrenes and as a triplet sensitizer in energy transfer catalysis. The singlet lifetime is sufficiently long to exploit the exceptional excited state reduction potential for the activation of 4-cyanopyridine. Photoinduced electron transfer generating the radical

• increased when the triplet efficiently reacts in a catalytic cycle such that turnover numbers exceeding 4400 are achievable with this organocatalyst. Keywords: energy transfer; laser spectroscopy; organocatalyst; photoredox; time-resolved spectroscopy; Introduction The emergence of photoredox chemistry in

• lifetimes, limiting their use in collision-based electron/energy transfer reactions unless high substrate concentrations are used [29][30]. In contrast, triplet states populated via intersystem crossing (ISC) have much longer lifetimes and can efficiently react at lower substrate concentrations [30

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• comparing the relative energy of the frontier molecular orbitals of arylamines with SeO2 could be a convenient measure to understand the differences in polymerization tendency. The relative energy of the frontier molecular orbitals of arylamines and SeO2 is shown in Figure 7. In an oxidative polymerization

• process, an electron is transferred from the HOMO of an arylamine donor to the LUMO of the SeO2 acceptor. The computed HOMO–LUMO energy difference (∆E) between arylamines and SeO2 decreased in the following order: o-anisidine − SeO2 > aniline − SeO2 > methyl anthranilate − SeO2. It revealed that the HOMO

• of methyl anthranilate was relatively buried, with a large energy gap (mismatch) between the donor and acceptor orbitals, which slowed down the oxidative polymerization process and allowed the alternative reaction pathway, electrophilic substitution of SeO2 on the aryl ring. This result was further

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• seven-membered ring and the remaining four 5-7 bicyclic compounds with the carbocation on the five-membered ring. The variations in energy within the groups of carbocations (i.e., 6-6 and two kinds of 5-7 bicyclic carbocations) can be ascribed to intramolecular repulsion interactions, as seen from non

• derived from germecrene A. Keywords: carbocation; germacrene A; hedycaryol; stability trend; terpenes; Introduction Terpenoids form a large and highly diverse group of natural products with a wide range of usage in the pharmaceutical, cosmetic, agricultural, food, and energy industry. Among their

• several significant processes, terpenoids play an indispensable role in cell-wall and membrane biosynthesis, sensing, plant defense, electron transport, or conversion of light into chemical energy [1][2]. Based on the number of hydrocarbon units, terpenes are classified into various families like

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• the molecule’s entire π-system including the 1,3-diphenyl substituents. This extensive delocalization of orbital density significantly raises the HOMO energy level and lowers the LUMO energy level compared to parent isobenzofuran (1). Conversely, both the HOMO and LUMO orbitals for compound 3 with 1,3

• -dimesityl substituents show reduced orbital density on the mesityl substituents compared to the phenyl substituents of 2. Likewise, 3 possesses a lower energy HOMO orbital and a higher energy LUMO orbital compared to 2. The π-systems for compounds 23, 24 and 25 with 2’,4’,6’-triethylphenyl, 2’,4’,6

Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines

• Vladislav V. Nikol’skiy,
• Mikhail E. Minyaev,
• Maxim A. Bastrakov and
• Alexey M. Starosotnikov

Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94

• fields of chemistry and materials science. These compounds are widespread in medicinal chemistry [1][2][3], production of high-energy-density compounds [4][5][6][7], and many others. In particular, isoxazolo[4,5-b]pyridines are of considerable interest due to their remarkable variety of biological

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

• Akanksha Ashok Sangolkar,
• Rama Krishna Kadiyam and
• Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

• Akanksha Ashok Sangolkar Rama Krishna Kadiyam Ravinder Pawar Laboratory of Advanced Computation and Theory for Materials and Chemistry, Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana-506004, India 10.3762/bjoc.20.93 Abstract Harnessing solar energy

• by employing chemical photoswitches in molecular solar thermal (MOST) energy storage systems is a topic of appealing research interest. However, incorporating all the features desired for an ideal MOST system in a single photoswitching couple is challenging. Inspired by experimental synthesis, herein

• we report our attempt to enhance both the thermochemical and photophysical properties in a single-bridged bicyclic diene (BBD)-based photoswitch by elongating the unsaturated bridge with different heteroatomic units. To elucidate the best elongation unit, the energy storage capacity and the TBR

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

• molecular ordering in solid-state organic semiconductors, thereby dictating charge transport pathways as well as carrier mobilities of both electrons and holes [4][5][6]. Furthermore, strong hydrogen bonding interactions effectively modulate energy levels of semiconducting materials, affecting the bandgap

• % weight loss value is increased by about 100 °C, particularly in the case of 1b as compared to the corresponding DCPQ 1a. This enhancement can be attributed to the synergistic effect of π–π and H-bonding interactions on solid-state cohesive energy. However, 3b and 7b exhibited a decrease in 5% weight loss

• from 388 to 423 nm, indicative of π–π* transitions. On the contrary, DPQDs exhibited more structured, blue-shifted bands with λmax from 357–400 nm. At the same time, DCPQs exhibit intramolecular charge transfer (ICT) bands at lower energy due to the dicyanopyrazinopyrazine moiety as a strong acceptor

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

• the electronic energy bands of graphene. Since the Fermi level is located at the Dirac point for neutral nanographene, edge states are half-filled like singly occupied molecular orbitals (SOMO) of radical states. Namely, nanographene sheets become magnetic and chemically active due to the edge states

• effect, ACFs were ground in a mortar before the measurement. Results and Discussion XPS spectra acquired in a wide binding energy region for ACFs and FeCp2-ACFs-150 are shown in Figure 1. Peaks of C1s and O1s were observed in ACFs, while C1s, O1s, and Fe2p peaks appeared in the spectrum for FeCp2-ACFs

• -150. Figure 2 shows the Fe2p spectrum for FeCp2-ACFs-150 in a narrow binding energy region. The binding energies of the Fe2p peaks are similar to the reported value for FeCp2 [16]. So, the Fe2p peaks observed in FeCp2-ACFs-150 indicate the successful introduction of the FeCp2 molecule into ACFs as

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• -Str. 29a, 18059 Rostock, Germany Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Liaoning, China 10.3762/bjoc.20.87 Abstract Carbonylation processes have become widely recognized as a versatile, convenient, and low-cost method for

Monitoring carbohydrate 3D structure quality with the Privateer database

• Jordan S. Dialpuri,
• Haroldas Bagdonas,
• Lucy C. Schofield,
• Phuong Thao Pham,
• Lou Holland and
• Jon Agirre

Beilstein J. Org. Chem. 2024, 20, 931–939, doi:10.3762/bjoc.20.83

• glycoprotein as pointed out by Crispin and collaborators [8], and more recently the realisation that high-energy ring conformations, a rare event in six-membered pyranosides, were present in ca. 15% of the N-glycan components of glycoproteins in the PDB [3]. Many of these findings originated the development of

• valid, the ring must be in the 4C1 chair conformation. This can be measured through the Cremer–Pople parameters θ and ψ [27]. Theta angles of 0° < θ < 360° indicate that the sugar may be in a higher-energy confirmation; therefore, caution should be placed on any conclusions drawn from the molecular

• conformational landscape of pyranose sugars. A well-modelled ᴅ-sugar would be expected to be in the lowest-energy conformation and have a theta angle close to 0° and would be indicated by a blue point; deviations from the ideal conformation are highlighted with a red cross. Right: Real space correlation

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• substituents. It is therefore unsurprising that the number of methods seeking to access these has increased in recent times. In 2022 Brown and co-workers reported a strain release [2π + 2σ] cycloaddition induced by triplet energy transfer for the synthesis of 1,2,4-BCHs and 1,2,5-BCHs [38]. Some earlier

• was also employed for the synthesis of 1,2,4-BCHs [35]. Heterocycle-substituted BCHs were accessed by [2π + 2σ] photocycloaddition by Glorius and co-workers [79] and Houk, Glorius and co-workers [80]. This reactivity was enabled by triplet energy transfer catalysis activating the heterocyclic

• by Lewis acid-catalysed cyclisation of bicyclobutanes with aldehydes [84] and polysubstituted 2-oxa-BCHs bearing more complex substitution patterns were synthesised by triplet energy transfer catalysis from benzoylformate esters and bicyclobutanes [85]. Reports of polysubstituted scaffolds larger

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• project WP20-1151. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract no. DE-AC05-00OR22725.

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• differences among alkenes. As demonstrated in the case of methylcyclopentene (Figure 1), the nucleophilicity of the exo-double bond is higher compared to the internal double bond. The higher energy of exo-alkenes compared to internal alkenes is well known and attributed to a less-effective hyperconjugation of

• C–H bonds into the alkene π-bond [30]. Before reviewing polar hydrochlorination reactions in detail, it is worth mentioning several statements which were made in the Sergeev review [12]: a) The activation energy for an anti-Markovnikov addition is at least by 30 kJ mol−1 higher than for normal

• concerning the polar hydrochlorinations the activation energy for an anti-Markovnikov addition is at least by 30 kJ mol−1 higher than for normal addition. Therefore, the formation of the anti-Markovnikov product via purely cationic intermediates is never observed. The only report for the formation of the

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• living organisms produce and use such metabolites as biocatalysts in nature. Therefore, it is thought that the production of HSMs has some physiological significance. For example, other microbial species reportedly activate energy metabolism and strengthen the cell membrane or walls in high-temperature

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• commercially available Kessil lamp of the same wavelength and intensity we observed a similar yield (Table 5, entry 5). Reducing the strength of the irradiation from 44 to 22 W had no impact, similarly using a more energetic wavelength afforded the same yield (Table 5, entries 6 and 7). When lower energy light

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• required for these redox reactions to progress is taken into consideration, a lowest unoccupied molecular orbital (LUMO) energy ≤ −4.0 eV (relative to vacuum) is required for air stable electron transport materials [2] and this is a common target for researchers developing these types of materials. In

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• of N,N,N',N'-tetraethylethynediamine and 1-morpholino-1-cyclopentene with empty C60 has been reported [17][23], while electron-rich styrene derivatives 1 and 2 can react with empty C60 only through a photoinduced SET pathway [19][22]. From these results, the energy gap between the HOMO of the alkene

• reactant 4, which has a larger energy gap between its HOMO and LUMO of Li+@C60 (1.92 eV). All reactions were conducted in the dark to avoid photoinduced SET reactions (Scheme 2). First, the reactivity was assessed by monitoring the reaction progress using a previously developed electrolyte-added HPLC

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

• effect remains if the local structure of the linker consisting of an alkyl group and a pyrene group is maintained. Therefore, it is likely that the kinetic behavior of a protein immobilized with a single PASE linker exhibits an activation barrier-type energy surface between the bi-stable conformations on

• graphene. We discuss the expected protein sensors when this type of energy surface appears and provide a guideline for improving the sensitivity, especially as an oscillator-type biosensor. Keywords: biosensor; DFT; PASE; protein; surface adsorption; Introduction Consideration of the atomic-scale motion

• stable configuration (conformation 1) in a straight form on graphene. There is at least one metastable bent configuration (conformation 2) on the potential energy surface. Besides, the reaction barrier of the conformational change of the PASE was determined. In this paper, we further examine a reaction

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

• ) addition because of a photoinduced energy transfer between porphyrins and the copper center. The fluorescence can be recovered by the addition of a bidentate pyrophosphate guest ligand, which disturbs the geometry of the system (octahedral complex) and thus lowers the energy transfer. Jang and co-workers

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

• ). The other two isomers, 2 and 3 (Figure 5b,c), with two CPPs tilted at 15.6° and 45.5°, are 2.5 and 4.2 kJ mol−1 less stable than complex 1, respectively. The stability among the isomers is low, and the activation energy for isomerization should be very low. Therefore, all isomers are expected to be

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• , lowering its LUMO energy, by withdrawing electron-density through a variety of covalent interactions. Green and sustainable approaches Solvent-free processes Alternative processes, that limit environmental pollution and toxic byproducts, came to the forefront of research for the introduction of novel