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Search for "calculations" in Full Text gives 911 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

  • Andrei Paraschiv,
  • Valentina Maruzzo,
  • Filippo Pettazzi,
  • Stefano Magliocco,
  • Paolo Inaudi,
  • Daria Brambilla,
  • Gloria Berlier,
  • Giancarlo Cravotto and
  • Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

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  • circumvent any possible solvent influence on yield calculations and both Si-MonoAm and Si-DiAm showed a high degree of derivatisation; 9.9 and 21 wt %, respectively, which correspond to 738 and 1090 μmol/g. The first derivative peak temperatures that indicate the point of the greatest rate of change in the
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Published 15 Jul 2025

Wittig reaction of cyclobisbiphenylenecarbonyl

  • Taito Moribe,
  • Junichiro Hirano,
  • Hideaki Takano,
  • Hiroshi Shinokubo and
  • Norihito Fukui

Beilstein J. Org. Chem. 2025, 21, 1454–1461, doi:10.3762/bjoc.21.107

Graphical Abstract
  • nucleophilic substitution of the thus generated alkoxide to form an oxygen-containing five-membered ring. At least, density functional theory (DFT) calculations support that the nucleophilic attack of methylenetriphenylphosphorane to the exo-methylene unit is slightly favorable over reaction with the carbonyl
  • signals due to the exo-methylene groups overlapped with the solvent signal in CD2Cl2. The thus obtained activation barriers of 3 and 5 were 11 and 12 kcal mol–1 at 263 and 253 K, respectively (Figure S27 in Supporting Information File 1). Previous DFT calculations at the B3LYP/6-31G(d) level of theory
  • suggested that the bathtub conformation of CBBC 1 is slightly unfavorable than the figure-eight conformation by 2.4 kcal mol−1 [21]. On the other hand, the current DFT calculations suggest that the bathtub conformation of bis-olefin 5 is rather favorable by 0.3 kcal mol−1, which is in accordance with the
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Published 14 Jul 2025

Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds

  • Lidia Zaharieva,
  • Vera Deneva,
  • Fadhil S. Kamounah,
  • Nikolay Vassilev,
  • Ivan Angelov,
  • Michael Pittelkow and
  • Liudmil Antonov

Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105

Graphical Abstract
  • OH functionality in compound 2 gives possibility to influence the tautomerism in this compound dynamically by protonation/deprotonation. The tautomeric and switching properties of compounds 1 and 2 have been revealed by using quantum-chemical calculations, UV–vis and NMR spectroscopy and UV
  • makes possible to analyze the tautomerism in 1 as a function of (E+KE) and KK. The NMR spectra of 1 in acetonitrile-d3 are in agreement with the above analysis of tautomeric equilibration based on theoretical calculations and UV spectra. At room temperature the proton signals are very broad and
  • K does not change it much (Table 1, the italicized values). The calculated energy barrier of process from 1KE to 1KK in acetonitrile (37 kcal/mol in Table 1) is relatively high and this process should be slow in the NMR time scale. The conclusion from these calculations is that the major conformer
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Published 10 Jul 2025

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

  • Kelsey Plasse,
  • Valerie Wright,
  • Guoshu Xie,
  • R. Bernadett Vlocskó,
  • Alexander Lazarev and
  • Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

Graphical Abstract
  • volume data (ΔV) was calculated for each reaction. Gaussian 09 was used to carry out the calculations at the b3lyp/6-311++g(d,p) level of theory. The molecular volume of each reactant and product (including all by-products that are part of the reaction scheme) was calculated and the overall volume
  • using density functional theory (DFT) with the Becke three-parameter exchange and Lee–Yang–Parr correlation (B3LYP) functional [49], along with the 6–311++G(d,p) basis set for gas-phase calculations of all compounds. After completing the molecular geometry optimizations, vibrational frequency
  • calculations were conducted to ensure that none of the optimized structures exhibited imaginary frequencies confirming that all structures corresponded to real local minima on the potential energy surface. For the volume calculations, the Gaussian keyword “volume” was used, which defines the molar volume as
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Published 02 Jul 2025

Oxetanes: formation, reactivity and total syntheses of natural products

  • Peter Gabko,
  • Martin Kalník and
  • Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

Graphical Abstract
  • loadings were necessary for ortho-substituted phenyls. Control experiments and DFT calculations revealed that the oxetane ring is formed before the tetrahydrofuran in the domino process. In 2023, Shigehisa and co-workers published a new cycloisomerisation strategy for the construction of oxetane rings from
  • still runs smoothly, if the aryl is substituted for cyclohexyl. The proposed mechanism, supported by control experiments, deuterium exchange studies and energy calculations, consists of the following steps: conjugate addition of the carbene to the allenoate, regioselective addition of the resulting
  • halogens, nitriles, alkenes and heteroaryls. On the other hand, this methodology suffers from relatively low diastereoselectivity as the dr lies between 1:1 and 2:1. DFT calculations suggested the reaction proceeds through nitrogen elimination, oxonium ylide 119 formation, homolytic cleavage and radical
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Published 27 Jun 2025

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

  • Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

Graphical Abstract
  • reported by Feng and co-workers (Scheme 24) [110]. Precursor 181 was annealed on an Au(111) surface at 300 °C, resulting in PAH 182 with two embedded azulene subunits. Spin-polarized density functional theory calculations predicted that PAH 182 would exhibit an open-shell singlet ground state, as it
  • revealed that none of the azulene subunits exhibits the characteristic azulene-like aromaticity. Additionally, both 186 and 187 show moderate open-shell biradical character, according to theoretical calculations. A similar strategy, leading to different types of skeletal rearrangements, was reported by Ma
  • substituents of precursor 188 after annealing. In contrast, all the other observed PAHs 189–194 result from oxidative ring-closure and skeletal ring-rearrangement reactions. Theoretical calculations revealed that nanographene 188 possesses an antiferromagnetic open-shell singlet ground state, whereas the other
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Published 26 Jun 2025

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

  • Jiangfei Chen,
  • Yi-Lin Qu,
  • Ming Yuan,
  • Xiang-Mei Wu,
  • Heng-Pei Jiang,
  • Ying Fu and
  • Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

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Published 24 Jun 2025

Selective monoformylation of naphthalene-fused propellanes for methylene-alternating copolymers

  • Kenichi Kato,
  • Tatsuki Hiroi,
  • Seina Okada,
  • Shunsuke Ohtani and
  • Tomoki Ogoshi

Beilstein J. Org. Chem. 2025, 21, 1183–1191, doi:10.3762/bjoc.21.95

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  • ], [4.3.3]_Br and [4.3.3]_2Br. To gain insight into the different reactivity between [3.3.3] and [4.3.3], theoretical calculations were performed at the ωB97X-D/6-31G(d,p) level of theory (Figures S901–S903 in Supporting Information File 1). Although distribution of the highest occupied molecular orbitals
  • copolymers.a Supporting Information Supporting information includes general information, synthetic procedures and compound data, NMR and MS spectra, HPLC charts, and results of PXRD, DSC, TGA, gas adsorption, and theoretical calculations. Supporting Information File 2: Experimental. Acknowledgements The
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Published 18 Jun 2025

Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups

  • Julius Seumer,
  • Nicolai Ree and
  • Jan H. Jensen

Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94

Graphical Abstract
  • . This study introduces a novel quantum mechanics-based computational workflow tailored for the regioselective prediction of C–H activation in the presence of DGs. Utilizing (semi-empirical) quantum calculations hierarchically, the workflow efficiently predicts outcomes by considering concerted
  • be predicted by calculation and comparison of the relative energies of the proceeding palladacycle intermediate, as postulated in the Bell–Evans–Polanyi (BEP) principle [10][11]. Focussing on the intermediates allows for easier automation of the calculations since a minimum instead of a saddle point
  • chemistry’s structural variability. Cao et al. [14] developed an automated workflow that predicts the regioselectivity of C–H activations using extensive DFT calculations on a HPC cluster using up to 600 nodes, each containing 16 Intel Xeon E5-2670 cores. They considered two possible reaction mechanisms, an
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Published 16 Jun 2025

A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones

  • Ashutosh Nath,
  • John Mark Awad and
  • Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92

Graphical Abstract
  • chromatography with 30:70 EtOAc/hexanes. Product structures were confirmed by 1H and 13C NMR analysis and X-ray crystal structure analysis of 8a. Density functional theory (DFT) calculations DFT computations were conducted utilizing Gaussian 16W with the B3LYP functional and the 6-31G(d,p) basis set [21][22
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Published 13 Jun 2025

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

  • Krishna Pandey,
  • Lucas X. Orton,
  • Grayson Venus,
  • Waseem A. Hussain,
  • Toby Woods,
  • Lichang Wang and
  • Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

Graphical Abstract
  • difference in binding constants as well as the isolation of two distinct molecular conformations of phenylalanine HIM 1 (Figure 1), DFT calculations were performed. The details of DFT calculations are shown in Table 1. For DFT calculations, we assigned two HIM macrocycles per LiBArF20 as found in the co
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Published 30 May 2025

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

  • Betty A. Kustiana,
  • Galuh Widiyarti and
  • Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

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Published 28 May 2025

Pd-Catalyzed asymmetric allylic amination with isatin using a P,olefin-type chiral ligand with C–N bond axial chirality

  • Natsume Akimoto,
  • Kaho Takaya,
  • Yoshio Kasashima,
  • Kohei Watanabe,
  • Yasushi Yoshida and
  • Takashi Mino

Beilstein J. Org. Chem. 2025, 21, 1018–1023, doi:10.3762/bjoc.21.83

Graphical Abstract
  • allylic amination of acetate 12 with isatin (11a).a Supporting Information Data of thermal racemization of 7, DFT calculations for investigating racemization mechanism of 7, general methods and materials, experimental procedures and characterization data, 1H, 13C and 31P NMR spectra for 9 and 10, 1H, 13C
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Published 23 May 2025

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

  • Chun-Yu Mi,
  • Jia-Yuan Zhai and
  • Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

Graphical Abstract
  • bridge cycle [36][37]. The excellent diastereoselectivity in this radical cyclization was further rationalized by DFT calculations, which suggests an energy discrepancy of the hydrogen atom transfer process from different faces of the resulting α-hydroxyl radical. Final reduction of the ketone and amide
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Published 22 May 2025

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

  • Daniel Straub,
  • Markus Gross,
  • Mona E. Arnold,
  • Julia Zolg and
  • Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Graphical Abstract
  • to break the symmetry. Here, the molecule consists of a pentalchloro phenyl and two tribromophenyl units (PCl-TBr2M) [55], or with two p-bromotetrafluorophenyl rings (PCl-TFBr2M) (see Figure 2d–f) [52]. DFT calculations for these mixed per- and trihalophenylmethyl radicals and their orbitals show a
  • = 697 nm with 2% (in cyclohexane) [10]. DFT calculations display that the Cz unit acts as an electron-donor moiety, facilitating a CT excited state with a clear C2 symmetry (see Figure 5b). Similarly, a biscarbazolylanthracenylmethyl radical has been reported; however, the ϕ has been too low to be
  • (because of spin selection rules forbidding the direct transition from the quartet to the doublet state). While for TTM and PTM substituted with weak donors such energetically low-lying quartet (Q1) states have been observed in TD-DFT calculations [20][62] and EPR spectroscopy [63], there are no such
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Published 21 May 2025

Recent advances in controllable/divergent synthesis

  • Jilei Cao,
  • Leiyang Bai and
  • Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

Graphical Abstract
  • thiols act as stoichiometric reductants. Mechanistic insights, elucidated through control experiments and DFT calculations, revealed that photoexcitation of diazo imide 41 triggers nitrogen extrusion (ΔG‡ = +10.0 kcal·mol−1), generating the triplet carbene intermediate Int-45. In DCM, this species
  • substrates 61. At 10 °C, the catalytic system consisting of NiBr₂(diglyme), oxazoline ligand, (EtO)₃SiH, and K₃PO₄(H₂O) achieved β-selective hydroalkylation. When the temperature was raised to 100 °C, the reaction selectively produced α-branched products. DFT calculations showed that at low temperatures, the
  • mechanistic experiments and DFT calculations, the authors proposed a possible mechanism for the reaction: first, DPZ is excited by light to form the excited state DPZ*, which then oxidizes bromide ions through single-electron transfer to generate corresponding radical anions. These radical anions undergo
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Published 07 May 2025

Dicarboxylate recognition based on ultracycle hosts through cooperative hydrogen bonding and anion–π interactions

  • Wen-Hui Mi,
  • Teng-Yu Huang,
  • Xu-Dong Wang,
  • Yu-Fei Ao,
  • Qi-Qiang Wang and
  • De-Xian Wang

Beilstein J. Org. Chem. 2025, 21, 884–889, doi:10.3762/bjoc.21.72

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  • . Synthesis of ultracycles. Supporting Information Supporting Information File 4: Experimental details and characterization data (including 1H NMR, 13C NMR, IR, and HRMS of precursor compounds and ultracycles, X-ray data for B4aH, theoretical calculations, and NMR titration data). Funding Financial support
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Published 06 May 2025

Data accessibility in the chemical sciences: an analysis of recent practice in organic chemistry journals

  • Sally Bloodworth,
  • Cerys Willoughby and
  • Simon J. Coles

Beilstein J. Org. Chem. 2025, 21, 864–876, doi:10.3762/bjoc.21.70

Graphical Abstract
  • data, but only 47 shared any primary data at all (Figure 3a). Of these, most (39) shared ‘MODEL’ data derived from in silico modelling – i.e., Cartesian coordinates associated with modelled structures in thermochemical calculations or binding studies (Figure 3b). 72% of these coordinates were given in
  • whether authors can select from alternative licenses or create a tailored license for their data. Reuse_3, ‘are code scripts necessary to reproduce findings available?’. For data that had been generated through software processing, algorithms or other calculations performed on primary data, only one paper
  • shared any code. Statistical outcomes shared in one Excel file reported only values, with no calculations. Discussion We frame our discussion (below) according to the four research questions posed in our introduction to this work and provide specific recommendations for strategies towards improved
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Published 02 May 2025

Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation

  • Zhihua Liu,
  • Ya-Zhi Chen,
  • Ji Wang,
  • Qingling Nie,
  • Wei Zhao and
  • Biao Wu

Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68

Graphical Abstract
  • solution into chloroform and controllable release into acidic solution [32]. Very recently, it was found that the receptor L alone can further extract solid Li2SO4 into DMSO solution [33], where sulfate binding is sufficiently strong to drive the solid–liquid extraction. DFT calculations suggest that an
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Published 29 Apr 2025

Substituent effects in N-acetylated phenylazopyrazole photoswitches

  • Radek Tovtik,
  • Dennis Marzin,
  • Pia Weigel,
  • Stefano Crespi and
  • Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

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  • often show higher quantum yields and increased thermal half-life of the metastable state. For the half-life, the choice of the heterocycle is crucial, as revealed through density functional theory (DFT) calculations, which showed that a 5-membered ring promotes the stability of the Z isomer [30]. Within
  • predicted using quantum chemistry to describe the Z→E isomerization in azobenzenes, namely: rotation, inversion, inversion-assisted rotation, and concerted inversion depending on the structure of the azobenzene [40][41][42][43][44]. For PAPs, Calbo et al. showed by DFT calculations that the inversion
  • activation enthalpy ΔH‡ and ΔS‡. In particular, NAc-PAP-CN showed a negative ΔS‡ = −30.0 ± 2.0 J/(mol·K), while NAc-PAP-OMe showed a relatively similar value (−39.0 ± 4.0 J/(mol·K)), hinting towards the same mechanism of relaxation operating for both compounds. Comparing these values to the calculations for
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Published 25 Apr 2025

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

  • Nguyen Tran Nguyen,
  • Vo Viet Dai,
  • Luc Van Meervelt,
  • Do Thi Thao and
  • Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

Graphical Abstract
  • , while density functional theory (DFT) calculations provided insights into their electronic properties, including reactivity and stability. This comprehensive approach, integrating synthesis, biological evaluation, and computational methods, highlights the potential of 4-(1-methylamino)ethylidene-1,5
  • ), electronegativity (χ), hardness (η), and softness (S). The calculations were based on established formulas, as described in literature [49]. Natural products and synthetic medicinal compounds containing a 2-pyrrolidinone subunit. The molecular structure of 5a, showing the atom-labelling scheme and displacement
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Published 24 Apr 2025

Synthesis and photoinduced switching properties of C7-heteroatom containing push–pull norbornadiene derivatives

  • Daniel Krappmann and
  • Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

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  • various positions of the NBD scaffold were envisioned, although such modifications have primarily been investigated theoretically thus far [25][26][27][28]. Recently, high-throughput calculations were conducted to screen a wide array of hetero-substituted NBD species. These studies predominantly
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Published 22 Apr 2025

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

  • Carola Tortora,
  • Christian A. Fischer,
  • Sascha Kohlbauer,
  • Alexandru Zamfir,
  • Gerd M. Ballmann,
  • Jürgen Pahl,
  • Sjoerd Harder and
  • Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

Graphical Abstract
  • hydrocyanation of hydrazones, catalyzed by a calcium–BINOL phosphate complex, has been studied for the first time both experimentally and computationally with DFT methods. A full catalytic cycle for the enantioselective synthesis of α-hydrazinonitriles is proposed based on insights gained from DFT calculations
  • –BINOL phosphate complex as catalyst. Herein, we report the development of the first Ca–BINOL phosphate-catalyzed asymmetric hydrocyanation of hydrazones and the results from DFT calculations to elucidate the mechanism of this transformation. Results and Discussion We first set out to study the
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Published 14 Apr 2025

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

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  • . Supporting Information File 1). The calculations were performed with two conformers of FimH, the open and the closed gate conformation, PDB 1KLF [45] and PDB 1UWF [46], respectively. These protein structures differ in the relative orientation of the so-called tyrosine gate, which is formed by Tyr48 and
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Published 08 Apr 2025

Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

  • Yuuki Ishii,
  • Minoru Yamaji,
  • Fumito Tani,
  • Kenta Goto,
  • Yoshihiro Kubozono and
  • Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

Graphical Abstract
  • recognized for fluorinated oligoacene systems [30][34][36]. The theoretical calculations suggest that, in the ground state, the polarization of the phenacene molecules inverted upon the introduction of fluorine atoms. As seen from electrostatic potential (ESP) mapping (Figure 5b), the phenacene cores are
  • , and their electronic spectral features were investigated. They displayed UV–vis and fluorescence spectra which were seemingly the same as those of the parent phenacene molecules in the solution phase although theoretical calculations predicted the MO energy levels of F8-phenacenes markedly lowered by
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Published 24 Mar 2025
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