Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• 15 mV. Raman spectroscopy Raman spectra were obtained using a Bruker® RAMII Fourier transform Raman spectrometer, purged with dry nitrogen. Excitation radiation at 1064 nm was generated by a Nd-YAG laser working at 500 mW. Backscattering collection of the Raman radiation was performed. Typically

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• structure of 16 was confirmed by serial X-ray crystallography using an X-ray free-electron laser (XFEL) [deposition number CCDC 2352718) [54][55]. We then performed a Strecker-type reaction on the aldehyde 16 to construct an α-aminonitrile 17. To our delight, the key intermediate, 2,3-diaminobenzofuran 11

• by small crystal analysis using an X-ray free-electron laser (XFEL) [54][55]. aSee Supporting Information File 1 for details. Supporting Information Supporting Information File 100: The experimental procedures and characterization data, including copies of NMR spectra and X-ray crystallographic

• analyses. Acknowledgements We thank Michihiro Sugahara, Hisashi Naito, and Shun Narai for supporting XFEL data collection. The synchrotron radiation experiments were performed at XFEL-SPring-8 Angstrom Compact Free Electron Laser (SACLA) with the approval of the Japan Synchrotron Radiation Research

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• force microscopy (AFM), electron microscopy (EM) techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM), and confocal laser scanning microscopy (CLSM) are the most common techniques for imaging self-assembled

• structures. Some of the key features and capabilities of these techniques are summarised in Table 1. CLSM is a fluorescence microscopy technique capable of acquiring high-resolution optical images at selected depths of the sample. This is achieved by exciting compounds with laser light and, by using a

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• assemblies, 2+-BF4− was further treated with NaPF6, LiB(C6F5)4, and NaPCCp for the ion-pair metathesis to afford ion pairs 2+-X− (X− = PF6−, B(C6F5)4−, and PCCp−) in 44–68% yields. The obtained ion pairs were characterized using 1H, 13C, and 19F nuclear magnetic resonance (NMR) and matrix-assisted laser

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• recorded on a JASCO FT/IR-4100 spectrometer in the range from 4000 to 600 cm−1. MALDI–TOF mass spectra were measured on a Shimadzu/Kratos AXIMACFR mass spectrometer equipped with a nitrogen laser (λ = 337 nm) and pulsed ion extraction, which was operated at an accelerating potential of 20 kV. THF solutions

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

• moieties absorbing ≈465 nm light (Figure 1b) should be excited at the resonance Raman spectroscopy using a 488 nm laser. This is supported by the observation that the excitation at 633 and 785 nm where 1b did not show any absorption (Figure 1b) did not give any Raman signals [20]. Extraction of SWNTs with

• diameter 0.8– 1.2 nm) were used. For centrifugal operation, Avanti J-E of Beckman Coulter and Hitachi Himac CS 150 GC II were used. Mass spectra were recorded on Bruker Autoflex III using the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) method with anthracene as the matrix for all

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

• thorough photochemical characterization is essential for efficient light-driven applications. In this article, the mode of action of a polyazahelicene catalyst (Aza-H) was investigated using laser flash photolysis (LFP). The study revealed that the chromophore can function as a singlet-state photoredox

• 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

• mechanism of the recently reported sulfonylation/arylation [45][46] reaction using laser flash photolysis (LFP). LFP is a powerful spectroscopic tool in photocatalysis that allows us not only to distinguish between energy and electron transfer but also to detect transient triplet states and radicals

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• perpendicularly. Unfortunately, the matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry of 3 afforded no molecular ion peak expected for adducts derived from Dip2Si and C60 while a base peak at m/z 720 due to C60 was observed probably because of the low stability of radical

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

• Evolution instruments (Horiba) with an excitation laser operated at 532 nm in the wavenumber range from 1000 to 2000 cm−1. FTIR spectra were obtained using an FT/IR-6600 (JASCO) in ATR method with a diamond prism. Magnetic susceptibility measurements were carried out by a superconducting quantum

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

• mode high-resolution matrix-assisted laser desorption ionization mass spectra showed the formation of the monoadducts at m/z 875.10431 (5a) and 861.08866 (5b), which were assigned to each molecular ion ([M]+ calcd for C70H12OLi (5a): 875.10427 and C69H10OLi (5b): 861.08862, respectively). The UV–vis

• , external standard), and carbon of the solvent for 13C (53.84 ppm, CD2Cl2). High-resolution matrix-assisted laser desorption ionization (HR-MALDI) mass spectra were obtained on a Bruker solariX 12T mass spectrometer with dithranol as a matrix. UV–vis absorption spectra were measured on a JASCO V-670 and a

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

• ]. Various biosensors have already been developed, many of which require immobilization of antibody proteins on graphene surface. Therefore, protein capture by linkers is used in a relatively large number of sensors. In the elastic wave measurement system, elastic waves are generated by laser irradiation and

• reflected light of the probe light. For such laser-based biosensors, graphene's conductivity can provide a unique advantage. In fact, the conductivity of multilayered graphene is highly anisotropic. Therefore, the use of multilayer graphene avoids the burning of biomaterials by lasers irradiated from the

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• overlay of streptavidin-Alexa Fluor 647 (Molecular Probes) at 1 µg/mL. The microarray slides were scanned with GenePix 4300A scanner instrument (50% laser power at PMT 350), and the image analysis (quantitation) was performed with GenePix® Pro 7 software. The results can be found in Supporting Information

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 flash photolysis by a ruby laser (λ = 694 nm) in combination with photostationary methods [41]. The data on the absorption maxima, decay times, and extinction coefficients for Z-11a and Z-12 obtained in these measurements significantly differed from those reported by Pummerer and Marondel [40]. In

• nm laser, compound 17a exhibited pronounced negative photochromism. The thermal backward reaction occurred within 120 min in the dark in acetonitrile. The photoisomerization quantum yields for compounds 17a (φZ→E = 0.13, φE→Z = 0.46), 17b (φZ→E = 0.01, φE→Z = 0.02), and 17c (φZ→E = 0.06, φE→Z = 0.20

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

• the plausible energy transfer from the local charge-separated (CS) state of the push–pull chromophore (namely N,N-diethylanilino (DEA)•+–TCBD•−) to the singlet excited state of C60 (1C60*). In transient absorption spectral measurements conducted via the femtosecond laser-flash photolysis of compound

• measuring the charge-separation and charge-recombination lifetimes of these molecules by laser-flash photolysis (excitation wavelength = 420 nm) and the resulting electron-transfer rates were plotted. In the measurements in toluene, the lifetimes of the CS states and charge-recombination events differed

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• film thickness was analyzed by laser confocal microscopy (Figure 5a, Table 1). The average thickness was ≈393 nm, whereas the edge of the film was much thicker (≈999 nm). In earlier studies, the CNTs in the dispersions were observed to flow and accumulate along the droplet's edge due to the coffee ring

• flowing air (200 mL/min) at a ramping rate of 1 °C/min. The Raman and absorption spectra were obtained from DWCNT thin film on a silicon substrate. The DWCNT thin film was prepared using vacuum filtration. Raman measurements were conducted using a HORIBA T64000 532 nm laser, while far-infrared (FIR

• -770 spectrometer. The film's thicknesses were measured using a laser confocal microscope (OLYMPUS, OLS-4500). (a) Size distribution of DWCNTs in dispersion by DCS measurements. (b) Optical microscopy image of the DWCNT dispersion. Scale bar is 100 µm. (a) Phase diagram of the DWCNT dispersion. The

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• photoluminescence behavior of thin films, steady-state and time-resolved PL spectra were acquired using an Oxford Instruments Optistat DN2 cryostat, which was cooled with liquid nitrogen. The PL decay curves were obtained using a PicoQuant LDH-D-C-375 laser as the excitation source, operating at a wavelength of 374

• , we utilized an EKSPLA NL300 laser, with a wavelength of 355 nm, as the excitation source to create charge carriers within the organic layer. By applying various positive and negative external voltages (U) to the samples using the Keithley precision 6517B electrometer, we were able to investigate hole

• of the vacuum-deposited films of compounds 6–9 on glass substrates covered by FTO electrodes. The current transients (a) for electrons recorded at the different voltages for the vacuum-deposited films of compound 7 in a diode-like structure ITO/film/Al. Excitation wavelength 355 nm, laser pulse

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• , such as alkyl halides. In this study, the thermal reaction of the La@C2v-C82 anion with benzyl bromide derivatives 1 at 110 °C afforded single-bonded adducts 2–5 with high regioselectivity. The products were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

• -electron reduction of Gd@C2v-C82 for the addition reaction to occur at room temperature [22]. Supporting Information File 1, Figure S1 depicts the three HPLC separation steps including recycling for the isolation. The matrix-assisted laser desorption/ionization time-of-flight (MALDI–TOF) mass spectra of 2a

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• efficiencies pointed out that DMB-TT-TPA (8) is among the best D–π–A modal fluorophores suitable for an OLED application. Moreover, the photophysical properties of DMB-TT-TPA (8) were investigated through time-resolved fluorescence studies (390 nm laser source in THF). The fluorescence lifetime (τ) of DMB-TT

GlAIcomics: a deep neural network classifier for spectroscopy-augmented mass spectrometric glycans data

• Thomas Barillot,
• Baptiste Schindler,
• Baptiste Moge,
• Elisa Fadda,
• Franck Lépine and
• Isabelle Compagnon

Beilstein J. Org. Chem. 2023, 19, 1825–1831, doi:10.3762/bjoc.19.134

• .19.134 Abstract Carbohydrate sequencing is a formidable task identified as a strategic goal in modern biochemistry. It relies on identifying a large number of isomers and their connectivity with high accuracy. Recently, gas phase vibrational laser spectroscopy combined with mass spectrometry tools have

• spectrometry (MS). In short, our technology is based on a mass spectrometric analysis – which is particularly powerful for the analysis of complex biological samples but does not readily elucidate isomers which have the same molecular mass – augmented with a infrared laser-based spectroscopic dimension (MS–IR

• wavelength-dependent laser-induced fragmentation yield. When the frequency of the laser is resonant with a vibrational mode of the molecule, the molecule absorbs the radiation and accumulates internal energy until fragmentation [13]. In previous works we have demonstrated that the monosaccharides or

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

• materials. Experimental Raman spectra were obtained in an Anton Paar spectrometer, Cora 5001 model, under an excitation laser line at 785 nm and 450 mW power source. The exposure time was around 160 ms and 1 accumulation. The sample powder was placed in a glass slide under the objective lens and performed

• photon counting [39] with a FluoTime 200 (PicoQuant). Excitation was provided using a 401 nm pulsed diode laser with repetition rates varying from 5.0 to 20 MHz. Fluorescence was collected perpendicular to excitation and passed through a polarizer set at the magic angle. The detection system consisted of

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• [11], laser dyes [12], and DR/NIR electroluminescent devices [13][14][15][16][17][18]. However, DR/NIR chromophores typically suffer from low photoluminescent quantum yields (PLQY) because of their intrinsic small band-gap energy causing larger vibronic coupling between the ground and excited states

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

• intrinsic decay rate of *PC1. Since no quenching by 1d or B2pin2 could be observed, the formation of PC1•− can be attributed exclusively to the thermodynamically favored reductive quenching of *PC1 by DBU. Nanosecond laser flash photolysis techniques were employed to directly monitor the back electron

• obtained by transient absorption spectroscopy with femtosecond pulsed laser excitation and were 2–3 orders of magnitude greater (e.g., keT (*PC1•−) = 6.8 × 1010 s−1) than the diffusion rate in DMSO (kdiff = 4.0 × 108 s−1 of 0.12 M 1d) confirming a preassociation of PC1•− and the substrate prior to PET

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• transient species of the dyads formed upon photoexcitation, the ns-TA spectra of NI-PTZ-F in HEX were studied (Figure 8a). Upon pulsed laser excitation, a positive absorption band centered at ca. 430 nm was observed, which is inconsistent with the characteristic triplet state absorption of the NI unit (460

• components to be used for Global analysis was estimated by performing a preliminary singular values decomposition (SVD) analysis. All data were chirp-corrected before global fitting. Nanosecond transient absorption spectroscopy The nanosecond transient absorption spectra were measured on a LP920 laser flash

• photolysis spectrometer (Edinburgh Instruments, Ltd., U.K.). The data (kinetic decay traces and the transient difference absorption spectra) were analyzed with the L900 software. All samples were deaerated with N2 for ca. 15 min before measurement and excited with a nanosecond pulsed laser (OPO nanosecond

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• of rotaxanes in crystalline molecular solids has been studied [38][39]. Rotaxane crystals bearing ferrocene motifs experienced elongation and contraction along the axes in a rapid and reversible manner by simply turning on and off a laser light irradiation, thus providing enough free space in order

• , respectively, and a methyl group at the para-position of the ended-aromatic ring of the azobenzene motif (R1), experienced an upward bending using a 360 nm diode pump solid state laser irradiation source. By irradiating crystals of 1a at 445 nm using a power of 4 mW, a reversible curling motion was observed

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• Orbitrap XL equipped with nitrogen UV laser (337 nm, 60 Hz, 8–20 μJ) in positive ion mode. For the CID experiment using the linear trap quadrupole (LTQ) helium was used as the collision gas and 2,5-dihydroxybenzoic acid (DHB) or (2-methylprop-2-en-1-yliden)malononitrile (DCTB) as the MALDI matrix