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

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

• photochemical instability, as evidenced by their low N–O bond dissociation energy (BDE ≈ 42 kcal/mol) [28], the reliance on toxic tin hydrides as reductants and the undesired radical recombination with reactive 2-pyridylthiyl radicals that leads to (alkylthio)pyridine byproducts [26]. More recently, N

• electronically excited substrate (*S) through an energy transfer (EnT) mechanism (path c). In addition to these mechanistic blueprints, the formation of charge-transfer complexes involving NHPI esters, as well as examples of photoinduced transition metal-catalyzed activation will be discussed. Depending on the

• photosensitizer in an energy-transfer (EnT) mechanism. This proposal was supported by fluorescence quenching measurements, as well as the direct excitation of 44 by UV irradiation, resulting in the formation of 45 in a 45% yield. According to this hypothesis, NHPI ester 44 would adopt a favorable conformation (46

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

•  1), the energetically preferred tautomer is the 14H-form 7a. The least stable 7H-isomer 7b conforms to a minimum on the corresponding potential energy surface. However, the stable wave function of 7b corresponds to an electronic state with a broken symmetry [20], indicating the presence of two

• = −1.39 V to a radical anion and then undergoes irreversible reduction at Е1/2RED2 = −1.91 V and irreversible oxidation at Е1/2OX = 0.48 V. These CV parameters are close to those recorded for triphenodioxazines [23]. The energy of the HOMO and LUMO orbitals assessed on the basis of the CV and electronic

• ). The DFT calculations [32] were performed using the Gaussian 16 program package [33] with the B3LYP functional [34] and the 6-311++G(d,p) basis set. The structures corresponding to minima on the potential energy surface and states with broken symmetry [20] were found through complete optimization of

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• /H2O (50:50; v/v) containing 0.1% formic acid. The parameters such as declustering and entrance potentials remained constant for MS and MS/MS were set up at 150 V and 10 V, respectively. Collision energy for MS and MS2 scan surveys was 10 V and 45 V, respectively, with a collision energy spread of 12 V

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

• been proposed in different fields such as medicinal chemistry [2][3][4][5][6], materials science [7][8], energy production, storage, and delivery [9][10][11][12][13], and electronics and optoelectronics [14][15][16]. Despite fullerenes having immense promise in all of these areas, their practical

•  1), unveiled the following reaction mechanism: initially, an oxidative coupling of the two alkyne moieties of our model 1a leads to the formation of INT 1, as previously reported [33]. This step, with a Gibbs energy barrier of 25.7 kcal·mol−1, is the rate-determining step for this process. Next, INT

• energy barrier (ΔΔG = 0.9 kcal·mol−1). The formation of intermediate α-INT 3 and β-INT 3 was found endergonic by 9.3 and 7.6 kcal·mol−1, respectively. Subsequently, both site isomers of INT 3 can undergo reductive elimination with barriers of 6.9 and 9.4 kcal·mol−1 to deliver the corresponding

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• accessible and have significant importance in the pharmaceutical industry, positioning them as appealing candidates for C(sp3) coupling due to their availability as a common chemical feedstock. However, due to the high bond dissociation energy of the C–O bond and the poor leaving ability of the hydroxy group

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

• the electron density on the N atom in the ground state due to the electronic effects of substituents facilitates charge transfer during excitation, which leads to a decrease in the energy of the transition and a bathochromic shift of the absorption band, and vice versa. Photochemistry of indigo

• behavior was explained by the large energy gap between the ground states of the E- and Z-forms of indigo as well as low activation energy of inversion for derivatives 13. In the same year, Nielsen, Hecht and co-workers achieved a remarkable stabilization of the Z-isomer of N,N'-disubstituted indigo 24 by

• zwitterionic resonance structures (Figure 3) increases in the excited state of indigo. This partial redistribution of charges, in turn, increases the electrostatic repulsion between the carbonyl groups in the Z-form (Figure 12) resulting in the larger energy gap between HOMO and LUMO and reduced stability for

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• energy, with a difference of Gibbs free energy with oxocarbenium 7 (39.2 kcal/mol) and 7’ (35.8 kcal/mol) incompatible with the reaction conditions. We therefore ruled out this possibility and suggest that aldehyde 3 is the main intermediate in this transformation (Scheme 3). Interestingly, the 1

• dihydronaphthalene 4. One-pot conversion of substrate 1 into 1-aryltetraline structure 6, and the proposed mechanism for its formation. Free-energy profile of the hypothesized [1,5]-sigmatropic hydrogen shift between 7 and 7’, (IEFPCM(CH2Cl2)-M06/6-311++G(2d,2p)//M06/6-31G(d,p) level of theory). Scope of substrates

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

• -order kinetics, indicating a bimolecular process. Furthermore, their findings elucidated a compelling linear free-energy relationship between the rate constants and electronic characteristics of the para-substituents of the DCV electrophiles, implying a dipolar, zwitterionic mechanism. The researchers

• also performed theoretical calculations, unveiling that the ring-opening step presented a higher energy barrier compared with the ring-formation step, particularly when the DCV compounds lacked aryl substituents. Subsequently, they successfully isolated the corresponding cyclobutene intermediate 13

• estimated energy barrier of ≈37 kcal mol−1 is reduced to ≈15 kcal mol−1 upon the electronic excitation of 59 and 60 to the T1 state. It is reasonable to consider that the phototriggered racemization is inhibited in the presence of O2 because O2 acts as a triplet-state scavenger. Osuka et al. synthesized two

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

• Laura Abella Gerard Novell-Leruth Josep M. Ricart Josep M. Poblet Antonio Rodriguez-Fortea Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, C/Marcel·lí Domingo 1, 43007 Tarragona, Spain Hydrogen and Power-to-X Department, Iberian Center for Research in Energy Storage

• (CIIAE), FUNDECYT-PCTEx, Polytechnic School of Caceres Building, Office CIIAE-C7, Av. Universidad s/n, 10003 Cáceres, Spain 10.3762/bjoc.20.10 Abstract Fullerene dimerization inside a peapod is analyzed at DFT level by characterizing the stationary points and deriving the energy profile of the initial

• electron microscopy (TEM) is a technique that has been used for a long time to provide images of molecules, but also to monitor the reactions triggered by the energy transfer of the electron beam to the atoms that build the molecules. In particular, the advances in TEM as well as in methods to anchor