Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts

• Kenta Tanaka,
• Yuta Tanaka,
• Mami Kishimoto,
• Yujiro Hoshino and
• Kiyoshi Honda

Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208

• otherwise noted, reagents were commercially available and were used without further purification. The UV absorption spectra were measured with a JASCO V-630 spectrometer. Cyclic voltammetry measurements were carried out with a computer-controlled potentiostat Model 660C (ALS Co., Ltd.). General procedure

• , computational data, absorption spectra, and cyclic voltammetry data. Acknowledgements We thank Prof. Mahito Atobe of Yokohama National University for cyclic voltammetry measurements.

Naphthalene diimides with improved solubility for visible light photoredox catalysis

• Barbara Reiß and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 2043–2051, doi:10.3762/bjoc.15.201

• the reference NDI 1 and the cNDI 2 (due to the better solubility) were determined in comparison by cyclic voltammetry in CH2Cl2 and in the presence of 0.1 M n-Bu4PF6 as conducting salt (see Supporting Information File 1). The cyclic voltagram of NDI 1 shows two reversible reductions and one

• conversions of diethyl 2-bromomalonate (13) with 1-octanal (12) and yields of product 14 by different photoredox catalysts (X). Supporting Information Supporting Information File 406: Synthetic protocols, copies of 1H and 13C NMR spectra, mass spectra, and cyclic voltammetry data. Acknowledgements Financial

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• were computed by density functional theory modelling (DFT) and characterized through UV–vis spectroscopy and cyclic voltammetry (CV) measurements. Finally, we report preliminary results obtained using these functional dyes as photosensitizers in dye-sensitized solar cells (DSSCs). Keywords: boron

• were investigated using UV–vis spectroscopy, and we show that they can absorb light up to 900 nm in solution and 1000 nm in solid state, after grafting on anatase-TiO2 mesoporous films. The cyclic voltammetry (CV) measurements indicate that the compounds have HOMO and LUMO energy levels suitable for an

• hindrance. 4. Electrochemical characterization Cyclic voltammetry of both BODIPY dyes was carried out in deoxygenated DCM solutions containing tetrabutylammonium hexafluorophosphate as salt (see Figure S24 and S25 in Supporting Information File 1), to investigate their oxidation and reduction processes as

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• properties of the three dyes were investigated by photoabsorption and fluorescence spectroscopy, Lippert–Mataga plots, cyclic voltammetry and density functional theory calculations. The photoabsorption maximum (λmax,abs) and the fluorescence maximum (λmax,fl) for the intramolecular charge-transfer

• . Therefore, the fact explains our findings that OUJ-2 shows large bathochromic shifts of the fluorescence maxima in polar solvents, as well as the Stokes shift values of OUJ-2 in polar solvents are much larger than those in nonpolar solvents. The cyclic voltammetry of OUY-2, OUK-2 and OUJ-2 demonstrated that

• , Lippert–Mataga plots, cyclic voltammetry and density functional theory (DFT) calculations, we reveal the photophysical and electrochemical properties of the (D–π–)2A fluorescent dyes OUY-2, OUK-2 and OUJ-2. Results and Discussion Synthesis The (D–π–)2A fluorescent dyes OUY-2 [2], OUK-2 [3][4] and OUJ-2

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• 3/DSS 4 (28,400 to 20,830 L mol−1 cm−1). No fluorescence was observed for each of the four heteroacenes DTT 1 to DSS 4 neither in DCM nor in THF. Electrochemical properties and electropolymerization The redox properties of the heterotriacenes 1–4 were investigated by means of cyclic voltammetry in

• Perkin Elmer UV/VIS/NIR Lambda 19 spectrometer. Cyclic voltammetry experiments were performed with a computer-controlled Autolab PGSTAT30 potentiostat in a three-electrode single compartment cell (3 mL). The platinum working electrode consisted of a platinum wire sealed in a soft glass tube with a

N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes

• Fabienne Speck,
• David Rombach and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 52–59, doi:10.3762/bjoc.15.5

• estimated to values of Ered(S/S−·) = −3.0 V [25]. In our initial photoredox catalyst screening [26], we identified 1-(N,N-dimethylamino)pyrene (16) having an excited-state reduction potential E*ox(P+·/P*) of −2.4 V (determined by cyclic voltammetry and E00). Thus, we are able to photoreduce 1,1

• . All N-phenylphenothiazines 1–11 were additionally characterized by cyclic voltammetry (Figure 3 and Table 1) [28]. We found the first oxidation half wave of the unsubstituted N-phenylphenothiazine (1) as a fully reversible process as it was described in literature recently [18]. The second oxidation

• transfer, BET = back-electron transfer). Reduction potentials Ered(X+·/X) of N-phenylphenothiazines 1–11 (determined by cyclic voltammetry using ferrocene as standard). Screening of reaction conditions for the methanol addition to α-methylstyrene (13a).a Supporting Information Supporting Information File

Bioinspired cobalt cubanes with tunable redox potentials for photocatalytic water oxidation and CO₂ reduction

• Zhishan Luo,
• Yidong Hou,
• Jinshui Zhang,
• Sibo Wang and
• Xinchen Wang

Beilstein J. Org. Chem. 2018, 14, 2331–2339, doi:10.3762/bjoc.14.208

• the different electronic properties have a significant influence on the optical performances, thus underlining the tuning effect of suitably substituted pyridine-based ligands for controlling the catalysts functions. The subsequent cyclic voltammetry (CV) experiments supported the above results, i.e

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• so-called mixed-valence dimer (12) ●+. A mixed-valence dimer can be identified by splitting of the first TTF oxidation potential into two distinguishable waves. This change in redox behavior can be followed by electrochemical methods such as cyclic voltammetry. Another indication for a mixed-valence

• TTF is preferred as a station for the wheel over the triazole unit. However, after oxidation, the more hydrophilic dication TTF2+ is less favored and the ring moves to the triazole. Both switching states were fully characterized by UV–vis, 1H,1H-NOESY NMR spectroscopy, and cyclic voltammetry. The

• and the rotaxane was isolated in 34% yield. NMR spectroscopy, cyclic voltammetry, and spectroelectrochemistry showed that the wheel translates to the dihydroxynaphthalene station upon TTF oxidation. The use of TTF in redox-switchable rotaxanes is not limited to the implementation into axle components

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• A. At the final step the iodine traps benzyl radical A to form the final product 3aa. Electrochemical studies Cyclic voltammetry (CV) experiments on a working glassy-carbon electrode were carried out for deeper understanding of the plausible reaction mechanism. As CH2Cl2 is not suitable as a solvent

• for anti-Markovnikov type regioselectivity of C–O and C–I bond formation. Electrochemical mechanistic studies based on cyclic voltammetry (CV) data confirm proposed reaction mechanism. Possible ways of using the obtained iodo-oxyimidated products via substitution of iodine atom were demonstrated

Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

• Jonas Weidner,
• Stefan Barwe,
• Kirill Sliozberg,
• Stefan Piontek,
• Justus Masa,
• Ulf-Peter Apfel and
• Wolfgang Schuhmann

Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121

• an EIS was recorded to determine the uncompensated electrolyte resistance and the potential was corrected accordingly. The conditioning of the catalyst was performed by cyclic voltammetry with 20 cycles between 0.97 V vs RHE and 1.43 V vs RHE with a scan rate of 100 mV s−1. The LSVs were measured

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• treatment. Cyclic voltammetry was used to determine the glycerol oxidation activity of the catalysts, and electrochemistry coupled with attenuated total reflection IR (ATR–IR) spectroscopy was performed to determine the product distribution in the thin electrolyte layer between the working electrode and the

• . Conclusion The effects of the alkali cations Na+ and K+ on the electrochemical oxidation of glycerol were investigated over Pd nanoparticles supported on carbon nanotubes. The CNTs used as support for the Pd NPs were either oxygen- or nitrogen-functionalized. Cyclic voltammetry showed that the achieved

• , 44780 Bochum, Germany 10.3762/bjoc.14.120 Abstract The effects of the alkali cations Na+ and K+ were investigated in the alkaline electrochemical oxidation of glycerol over Pd nanoparticles (NPs) deposited on functionalized carbon nanotubes (CNTs). The electrocatalytic activity was assessed by cyclic

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• 1 towards aromatic guests (anthracene, pyrene) in solution was observed and the formation of a cryptand–pyrene complex was revealed by cyclic voltammetry only after the adsorption of the cryptand on a graphite surface (electrode). In a more recent paper [33], authors who reobtained our cryptand 1

An unusual thionyl chloride-promoted C−C bond formation to obtain 4,4'-bipyrazolones

• Gernot A. Eller,
• Gytė Vilkauskaitė,
• Algirdas Šačkus,
• Vytas Martynaitis,
• Ashenafi Damtew Mamuye,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2018, 14, 1287–1292, doi:10.3762/bjoc.14.110

• afforded the corresponding 2,2',4,4'-tetrahydro-3H,3'H-4,4'-bipyrazole-3,3'-dione, whereas it was shown by EPR spectroscopy and by cyclic voltammetry that the reaction obviously proceeds via a radical mechanism [32]. To the best of our knowledge, the only such dimeric species with ester functions at

Investigations of alkynylbenziodoxole derivatives for radical alkynylations in photoredox catalysis

• Yue Pan,
• Kunfang Jia,
• Yali Chen and
• Yiyun Chen

Beilstein J. Org. Chem. 2018, 14, 1215–1221, doi:10.3762/bjoc.14.103

• -donating 3,4-dimethoxy groups. Cyclic voltammetry measurements were also carried out for BI-alkynes 3a–f, in which the reduction potential (Ep re) indicated the electron-accepting capacity of the BI-alkynes. As expected, the reduction potential of 3a was increased with electron-deficient 3,4-difluoro

• substituents on the benziodoxole, and was decreased for 3f with electron-donating 3,4-dimethoxy groups. It is interesting to note that the effect of single substitution on benziodoxoles in 3b, 3d and 3e was insignificant and sporadical in both 13C NMR spectroscopy and cyclic voltammetry experiments. We next

• % yield of 5a was obtained with 3,4-dimethoxy-substituted BI’-alkyne 3f. Being consistent with the 13C NMR spectroscopy and cyclic voltammetry experiments, the effect of single substitution on the benziodoxole was insignificant and no improvement was observed. We also tested the secondary alkyl

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• expressed by the pKR+ value, which is the affinity of the carbocation toward hydroxide ions. The pKR+ value for cation 61 was determined to be 4.7 spectrophotometrically. The reduction potential of the cation 61 was determined as −0.46 and −1.07 V by cyclic voltammetry in acetonitrile. The oxidizing ability

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• absorption spectroscopy, viscosity measurement, cyclic voltammetry and molecular modeling (Figure 9) [93]. Docking results confirmed that these complexes have the ability to interact with the minor groove of the ct-DNA. In addition, the authors confirmed that in presence of ascorbic acid, these complexes

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• electrosynthesis. Keywords: cyclic voltammetry; ferrocene; paramagnetic NMR spectroscopy; redox mediator; spectroelectrochemistry; Introduction Since its discovery, ferrocene (FcH) has been established as versatile redox-active building block [1][2][3]. Ferrocene can be reversibly oxidized to the 17 valence

• monitor reaction progress and stability are important issues. These fundamental aspects will be addressed in this study. Herein, a detailed study of the properties of 1–4 and their ferrocenium ions 1+–4+ in solution is reported including electrochemical methods (cyclic voltammetry and square wave

• carried out on a BioLogic SP-50 voltammetric analyzer using a platinum working electrode, a platinum wire as counter electrode, and a 0.01 M Ag/AgNO3 CH3CN electrode as reference electrode. The measurements were carried out at a scan rate of 100 mV s−1 for cyclic voltammetry experiments and 100 mV s−1 for

Electrochemically modified Corey–Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene

• Fabiana Pandolfi,
• Isabella Chiarotto and
• Marta Feroci

Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76

• , temperature, working potential and amount of consumed charge [24]. Our group intensively investigated the electrochemical behavior of 1,1-dibromoalkenes by means of cyclic voltammetry and electrolyses [25] and we reported the selective synthesis of vinyl bromides through the cathodic reduction of 1,1

Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives

• Feng-Ming Xie,
• Qingdong Ou,
• Qiang Zhang,
• Jiang-Kun Zhang,
• Guo-Liang Dai,
• Xin Zhao and
• Huai-Xin Wei

Beilstein J. Org. Chem. 2018, 14, 869–874, doi:10.3762/bjoc.14.73

• CEPDO and CBPDO are expected to be applied to PhOLED as a blue phosphorescent host material. Electrochemical properties The electrochemical properties of CEPDO and CBPDO were studied by cyclic voltammetry (CV) measurements in deoxygenated DCM solution with 0.1 M tetrabutylammonium hexafluorophosphate as

• the supporting electrolyte. The cyclic voltammograms are shown in Figure 3. Cyclic voltammetry was measured with a glassy carbon working electrode, a platinum wire counter electrode, a saturated Ag/AgCl reference electrode, ferrocenium-ferrocene (Fc+/Fc) as the internal standard and tetrabutylammonium

Anodic oxidation of bisamides from diaminoalkanes by constant current electrolysis

• Tatiana Golub and
• James Y. Becker

Beilstein J. Org. Chem. 2018, 14, 861–868, doi:10.3762/bjoc.14.72

• studied by cyclic voltammetry and all of their redox potentials were found to be irreversible in acetonitrile. Their first oxidation potentials (in the range of 2.1–2.35 V vs Ag/AgCl) are summarized in Table 1. The first and second columns indicate that the longer the spacer the higher the oxidation

• -nitrobenzene derivative) was dried, weighed and verified by NMR spectra. The isolated yields of the bisamides were around 72–86%. General methods Instruments used in this study for 1H NMR and 13C NMR measurements, mass and IR spectra, high-resolution mass analyses, and cyclic voltammetry were described in [23

D–A–D-type orange-light emitting thermally activated delayed fluorescence (TADF) materials based on a fluorenone unit: simulation, photoluminescence and electroluminescence studies

• Lin Gan,
• Xianglong Li,
• Xinyi Cai,
• Kunkun Liu,
• Wei Li and
• Shi-Jian Su

Beilstein J. Org. Chem. 2018, 14, 672–681, doi:10.3762/bjoc.14.55

• fabrication of OLEDs. In order to characterize their electrochemical properties, cyclic voltammetry (CV) measurements were conducted to measure their oxidation potentials (Eox) and reduction potentials (Ered). Ionization potential (IP) and electron affinity (EA), which approximate to their HOMO and LUMO

• platinum wire counter electrode at a scanning rate of 100 mV s−1 against a Ag/Ag+ (0.1 M of AgNO3 in acetonitrile) reference electrode were utilized for cyclic voltammetry measurements. UV–vis absorption spectra were measured using a HP 8453 spectrophotometer and PL and LTPL spectra were measured with a

Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands

• Rebecca Pittkowski and
• Thomas Strassner

Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54

• atmosphere, into liquid nitrogen. Spectroscopic grade 2-methyltetrahydrofuran (2-MeTHF) was purchased from ABCR and used as received. Cyclic voltammetry Electrochemical measurements were performed with a BioLogic SP-150 potentiostat in degassed, dry N,N-dimethylformamide using a Pt counter electrode, a

Electrochemical Corey–Winter reaction. Reduction of thiocarbonates in aqueous methanol media and application to the synthesis of a naturally occurring α-pyrone

• Ernesto Emmanuel López-López,
• José Alvano Pérez-Bautista,
• Fernando Sartillo-Piscil and
• Bernardo A. Frontana-Uribe

Beilstein J. Org. Chem. 2018, 14, 547–552, doi:10.3762/bjoc.14.41

• derivatives [32][33], showing a convenient electrochemical window with graphitic electrodes (−1.75 to 1.25 V vs Ag/AgCl) and giving good environmental compatibility. Cyclic voltammetry of thiocarbonates 4 and 6 using a vitreous carbon electrode, showed two irreversible reduction peaks located at −1.18 and

• first reduction peak observed in cyclic voltammetry (−1.45V vs Ag/AgCl) in a divided (sintered glass) H-type cell fitted with a reticulated vitreous carbon cathode and a stainless steel anode (see Supporting Information File 1 for details). When 2.2 F/mol were consumed (ca. 1.5 h), TLC control of the

• -alkene isomer. The use of graphite electrodes instead of the reticulated vitreous carbon eroded the chemical yield to 80% (Table 1, entry 2). Cyclic voltammetry analysis of 4 showed a second reduction peak at −1.6 V (Figure 1), a value that agrees with that for reduction of the α,β-unsaturated ester

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• characterised by SEM and cyclic voltammetry. A Pd/C to Nafion ratio was established at 60:40 for each electrocatalytic layer irrespectively of the Pd loading in the electrocatalytic layer. Figure 2 depicts the SEM micrographics using back scattering electrons for both Pd0.02/C/T and Pd0.20/C/T electrodes

• in 0.5 M H2SO4 using cyclic voltammetry (CV) at a scan rate of 50 mV s−1 (potential interval of 0.1 and 1.2 V vs Ag/AgCl). The CV diagram shown in Figure 3 represents a typical pattern for the electrochemical behaviour of Pd bar electrode where a broad anodic peak is associated to the oxidation of

• were obtained using a Hitachi S-3000N microscope with backscattered electron signal. Electrochemical surface characterisation of the distinct Pdx/C/T electrodes was explored by cyclic voltammetry (CV). CV measurements were performed using a PGSTAT30 Autolab system. A 0.5 cm × 1.0 cm Pdx/C/T electrode

The selective electrochemical fluorination of S-alkyl benzothioate and its derivatives

• Shunsuke Kuribayashi,
• Tomoyuki Kurioka,
• Shinsuke Inagi,
• Ho-Jung Lu,
• Biing-Jiun Uang and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2018, 14, 389–396, doi:10.3762/bjoc.14.27

• -butyl p-chlorobenzothioate (1b), and S-butyl p-fluorobenzothioate (1c) were determinded by cyclic voltammetry (CV). The compounds did not exhibit clear oxidation peaks, however, discharge started at around +2.3 V to +2.4 V vs SCE as exemplified in Figure 1 (CV curves of 1a). Thus, it was found that

• CDCl3. The chemical shifts for 1H, 13C and 19F NMR spectra are given in δ (ppm) from internal TMS, CDCl3 and monofluorobenzene, respectively. Cyclic voltammetry was performed using an ALS Instrument model 600A. Preparative electrolysis experiments were carried out with Metronnix Corp. (Tokyo) constant

• current power supply model 5944 by monitoring electricity with a Hokutodenko Coulomb/Ampere-hour meter HF-201. Cyclic voltammetry measurements Cyclic voltammetry was carried out in 0.1 M Bu4NBF4/MeCN using a glass cell. A platinum disk electrode ( = 0.8 mm) was used as a working electrode. A platinum