Search results
Search for "anode" in Full Text gives 80 result(s) in Beilstein Journal of Organic Chemistry.
Diastereoselective anodic hetero- and homo-coupling of menthol-, 8-methylmenthol- and 8-phenylmenthol-2-alkylmalonates
Beilstein J. Org. Chem. 2017, 13, 33–42, doi:10.3762/bjoc.13.5
- ], and in intermolecular coupling of radicals generated by anodic decarboxylation of carboxylic acids [15][16]. At the anode radicals can be generated by anodic decarboxylation of carboxylic acids in molar quantities, in a simple procedure, unaffected by cage effects and in large diversity. For that
- for constant temperature control, capacity: 3 mL (micro beaker-type cell). Platinum foils serving as anode and cathode materials (platinum foils: 1 × 1 cm). Convection was achieved by magnetic stirring. Current source: Heinzinger galvanostat – potentiostat HN 600–600 and TNs 300–1500. General
Effects of solvent additive on “s-shaped” curves in solution-processed small molecule solar cells
Beilstein J. Org. Chem. 2016, 12, 2543–2555, doi:10.3762/bjoc.12.249
- properties, which unfortunately results in s-shaped J–V curves and poor performance. We show that this is due to non-ideal phase separation, specifically a preferential migration of the electron acceptor to the bottom anode interface. This can, however, be mitigated through appropriate processing, using a
- shown by Tan and co-workers that in some cases, when PEDOT limits the voltage in solar cells, casting methanol on top of the layer will improve efficiency [63]. The methanol has been shown to effectively deepen the work function of the anode layer while not significantly disrupting the morphology
- . Specifically, this improves the extraction rate of holes at the anode interface. An enhanced hole extraction rate at the semiconductor/anode interface will reduce the accumulation of holes near the electrode, thereby preventing the screening of the internal field and suppressing recombination. The reduction of
Synthesis and characterization of benzodithiophene and benzotriazole-based polymers for photovoltaic applications
Beilstein J. Org. Chem. 2016, 12, 1629–1637, doi:10.3762/bjoc.12.160
- a blend of π-conjugated polymer (electron donor) and fullerene derivative (electron acceptor) sandwiched between two electrodes (anode and cathode) [1][2][3][4]. Noticeable achievements have been recorded in terms of the power conversion efficiency (PCE) of lab-scale single junction BHJ PSCs
Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells
Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142
- solvent of chloroform/1,8-diiodooctane (DIO) (98:2, v/v). The thickness of the active layer was controlled within the range of ca. 40–90 nm by varying the rotation speed during spin-coating. A 6 nm thick MoO3 layer as a hole extraction layer and a 100 nm thick Ag anode were vacuum-deposited on the active
3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells
Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134
- absorption and high carrier diffusion length as excellent features of the perovskite materials. The development of efficient hole-transporting materials (HTMs), which extract a hole from the perovskite layer and transport it to the anode, is also significant for the further improvement of the PSC
Synthesis and photophysical characteristics of polyfluorene polyrotaxanes
Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288
- the work function of ITO (anode) and Al (cathode) (d). Representative AFM images obtained over 3 × 3 µm2 areas of the non-rotaxane 3 (a), 3·TM-βCD (b) and 3·TM-γCD (c) polyrotaxanes. Synthetic route of 3·TM-βCD and 3·TM-γCD polyrotaxanes, and the non-rotaxane counterpart 3. Physicochemical
A new method for the synthesis of α-aminoalkylidenebisphosphonates and their asymmetric phosphonyl-phosphinyl and phosphonyl-phosphinoyl analogues
Beilstein J. Org. Chem. 2015, 11, 1418–1424, doi:10.3762/bjoc.11.153
- mmol) were added to a glass beaker (25 mL) equipped with a cylindrical Pt mesh anode (20 cm2) and a rotating flat cathode (platinised titanium, 1.2 cm2). In the case of 1-(N-acetylamino)methylphosphonate (5a), NaCl (70 mg, 1.2 mmol) was placed in the beaker in its entirety at the beginning of oxidation
- )methylphosphonate (5a) or in three portions for derivative 5b (as described above for Procedure A), and SiO2-Pip (150 mg, 0.15 mmol) or MeONa (0.6 mL methanolic solution, 0.3 mmol), were added to a glass beaker (25 mL) equipped with a cylindrical Pt mesh anode (20 cm2) and a rotating flat cathode (platinised
Cathodic hydrodimerization of nitroolefins
Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131
- 1 the dimer 2 is obtained in 88% material yield and 90% current yield. Presumably the protons are generated at the anode by oxidation of residual water and/or the solvent DMF. A major source of residual water could be the very hygroscopic tosylate as one of the reviewers suggested. The conditions of
- appears at the cathode, which disappears at the anode. This indicates the formation of coloured nitroalkyl anions and their decolourization by protonation. The nitroalkenes were obtained by condensation of aldehydes with nitroalkanes (Scheme 3, Table 3) [21][22]. For work-up unreacted aldehyde was removed
Trifluoromethyl-substituted tetrathiafulvalenes
Beilstein J. Org. Chem. 2015, 11, 647–658, doi:10.3762/bjoc.11.73
- extremely soluble, a consequence of the presence of the CF3 groups and there was no crystal growth on the anode. However, with 1c as electroactive donor molecule and (n-Bu4N)(FeCl4) as electrolyte, layering of the CH2Cl2 solutions after electrolysis with pentane afforded crystals of a 1:1 phase formulated
TTFs nonsymmetrically fused with alkylthiophenic moieties
Beilstein J. Org. Chem. 2015, 11, 628–637, doi:10.3762/bjoc.11.71
- immediately before its use. The system was sealed under nitrogen and after ca. 3 days, using a current density of 1 μA·cm−2, dark brown plate-shaped crystals were collected in the anode and washed with dichloromethane. Redox properties Cyclic voltammetry data were obtained using a BAS C3 Cell Stand. The
Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption
Beilstein J. Org. Chem. 2015, 11, 473–480, doi:10.3762/bjoc.11.53
- using the most productive anode materials. Under the conditions described, the electrochemical process usually resulted in moderate yields of 1 <2.0 wt % per electrolysis run but the selectivity towards vanillin (1) formation is outstanding (Figure 1). The only other volatile byproduct formed in much
- observed. Besides the applied anode materials, the current density has a tremendous influence on the achievable yield. Rather low current densities <2.0 mA∙cm−2 usually result in the highest yields of vanillin (1) independent of the electrode materials. Especially, Co-based materials are very sensitive to
- improve the accessibility of possible reaction sites located rather inside the lignin particle to the anode surface and high temperatures >100 °C are usually chosen for efficient degradation processes. Due to limited solubility of the commonly used Kraft lignin in aqueous systems, it was necessary to set
Electrochemical oxidation of cholesterol
Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45
- -compartment glass cell equipped with platinum mesh electrodes (cathode and anode) was filled with a cholesteryl acetate (1a) solution in acetonitrile containing ammonium tetrafluoroborate as a supporting electrolyte. The constant potential technique mainly afforded 7-hydroxylated products (7a and 8a; 19–38
- oxygen is possible. A stereoselective electrochemical method of the chlorination of steroidal Δ5-olefins was described by Takayama et al. [38]. The oxidation of cholesterol was carried out in an undivided cell under constant current conditions in CH2Cl2/MeCN/H2O (2:2:1), the cathode and anode being
- chlorination of some Δ5-steroids (Scheme 5) was reported by Milisavljević and Vukićević [40]. The electrolyses were carried out in dichloromethane under galvanostatic conditions with a graphite anode in an undivided cell. The supporting electrolyte tetraethylamonium chloride was a source of chloride ions
Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions
Beilstein J. Org. Chem. 2015, 11, 280–287, doi:10.3762/bjoc.11.32
- (galvanostatic) electrolysis [4]. When a constant current is passed through an electrolysis cell, the potential at the anode increases until it reaches that of the substrate in solution with the lowest oxidation potential. It then remains constant at that potential until the effective concentration of the
- substrate at the anode decreases to the point that the rate of substrate oxidation is small relative to the rate of electron transfer. At that point, the potential at the anode begins to increase and the selectivity of the reaction for the initial substrate is lost. When a low current density is used for
- the reaction. In this way, a series of substrates can be selectively oxidized using the same reaction conditions even if the substrates have significantly different oxidation potentials. For most of the following cases discussed, reticulated vitreous carbon (RVC) is used as a highly porous anode
Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes
Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18
- iodide were placed in the anode chamber. The reaction was performed at constant current electrolysis (10 mA) at 0 °C. It is considerable that the presence of 2,6-lutidine is crucial for a successful reaction. In the absence of 2,6-lutidine only traces of the product can be observed and oxidation of the
- acetonitrile. Then, the cell was equipped with a platinum plate anode and cathode and electrolysed under a constant current (10 mA, 6.67 mA/cm2) at 20 °C until completion was detected by TLC and GC–MS analysis. Then, 15 mL water were added, the mixture was extracted with diethyl ether (three times 15 mL
- fiber anode and carbon fiber cathode. Each chamber was charged with 10 mL TBABF4 solution (0.3 M in acetonitrile) and 2,6-lutidine (2.0 equiv). The anodic chamber was charged with the 1,4-diene (1.0 equiv) and sodium iodide (1.1 equiv). Constant current electrolysis (10 mA) was carried out at 0 °C until
3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates
Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16
- substrates (sterol donors, sugar alcohol) and the resulting glycoconjugate, the possibility that side processes will occur increases as the anode potential is more positive and the glycoconjugate concentration grows. A series of blank experiments proved that the electrochemical activation of i-steroidal
- electrolysis the potential of the anode was monitored and the process was stopped when the potential reached the value of +2.3 V vs Ag/0.1 M AgNO3 to avoid the occurrence of undesired oxidation processes. The reactions were also monitored by TLC and stopped when no further increase in the concentration of the
- used as an anode. All measurements were performed at 25 °C. The sugar (1,2:3,4-di-O-isopropylidene-α-D-galactopyranose; 7) [9] and steroidal substrates, 3α,5α-cyclocholestan-6β-ol (i-cholesterol; 6a) [10], 6β-methoxy-3α,5α-cyclocholestane (6b) [11], and 6β-ethoxy-3α,5α-cyclocholestane (6c) [12], were
Highly selective electrochemical fluorination of dithioacetal derivatives bearing electron-withdrawing substituents at the position α to the sulfur atom using poly(HF) salts
Beilstein J. Org. Chem. 2015, 11, 85–91, doi:10.3762/bjoc.11.12
- -withdrawing effect of a substituent greatly affects the electron-transfer step from the substrate to the anode. At first, anodic fluorination of ethyl α,α-bis(phenylthio)acetate (1b) [30][31] was carried out at platinum plate electrodes in an undivided cell using various solvents in the presence of Et3N·3HF
The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions
Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323
- introduction of the nucleophile to the C–X bond that contains the electroauxiliary (Scheme 4). Similarly, α-silyl-carbamates undergo low potential anodic oxidation reactions with complete regiocontrol and in special cases diastereoselectivity [34][35]. Interestingly, a porous graphite felt anode and a
- anode and a platinum wire coil is used as the cathode; the flow cell is placed into a dry ice bath to maintain the −78 °C temperature required. Cation flow systems can be used to prepare individual molecules and combined with the concept of combinatorial chemistry to generate libraries of compounds. A
- are anode and cathode) (viz. Figure 2). This technique of microflow mixing can also be applied to the synthesis of polymers [29]. A single channel miniaturised microfluidic electrolysis cell that is modular with other microfluidic techniques has now been developed to perform anodic methoxylation
Recent advances in the electrochemical construction of heterocycles
Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303
- , resulting in N-tosylated pyrrolidine products (Scheme 2, X = NHTs) [35][36]. The reactions can be carried out under galvanostatic conditions (C.C.E. = constant current electrolysis) at room temperature in an undivided cell using a vitreous carbon anode. The presence of a proton scavenger is necessary in
- oxidation of catechol in the presence of 4-hydroxycoumarin was reported by Tabaković et al. (Scheme 25, left) [69]. Using an undivided cell, an aqueous sodium acetate electrolyte and a graphite anode, the product was obtained in 95% yield. In a similar fashion, benzofurans of type 68 and 69 were synthesized
Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells
Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283
- molecules [24][30][52], these devices do show a comparable photoinduced spectral response. A comparatively low fill factor of 26–27% was observed as a result of poor energy level alignment at the anode side leading to low efficiency. Other parameters governing performance such as short-circuit current
Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids
Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260
- order to close the electron cycle. Electrons supplied at the cathode must emerge from an oxidation reaction occurring at the anode (Scheme 6). The electrochemical system should be optimized to prevent unfavorable interference between both reactions, since such conflicts cause electric current to be lost
- clear further in this review. An overview of different possible setups for obtaining carboxylic acids is given in Scheme 6. Electrocarboxylation reactions can either be conducted with a sacrificial anode, like magnesium or aluminum, or with an inert anode, like platinum or carbon. Most research has been
- , the gradual consumption of the anode material is a major drawback for industrial applications. Not only is it rather expensive to consume such large amounts of metal; it also strongly hinders the implementation of a continuous process. Additionally, in order to obtain the free acids, an acid
The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units
Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222
- , IP and EA compared to any of the constituents, which is necessary for electronic applications. The diagram with HOMO/LUMO levels and the work function of the indium tin oxide (ITO) coated glass substrates with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (anode) and Ca or Al
- compounds in addition to the work function of the indium tin oxide (ITO) coated glass substrates with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (anode) and Ca or Al (cathode) are available. Supporting Information File 554: Characterization data of the compounds: FTIR, 1H NMR
Domino reactions of 2H-azirines with acylketenes from furan-2,3-diones: Competition between the formation of ortho-fused and bridged heterocyclic systems
Beilstein J. Org. Chem. 2014, 10, 784–793, doi:10.3762/bjoc.10.74
- spectrometers. IR spectra were recorded on a Bruker TENSOR 27 spectrometer for tablets in KBr. Single-crystal X-ray data for 3a were collected at 100 K on a Bruker Proteum R diffractometer (FR-591 rotating anode generator, Pt-135 CCD detector) equipped with Cobra (Oxford Cryosystems) open-flow cryostat. Data
Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor
Beilstein J. Org. Chem. 2013, 9, 1698–1704, doi:10.3762/bjoc.9.194
- AXS, Berlin, Germany) with an air-cooled molybdenum anode for X-ray generation. The excitation settings were 50 kV and 750 mA and quartz glass disks were used as sample carriers. The analysis was performed by signal integration over 500 seconds. For the determination, the signal of gallium (Kα1
Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes
Beilstein J. Org. Chem. 2013, 9, 800–808, doi:10.3762/bjoc.9.91
- methods [1][2][3][4][5][6]. A radical ion formed at a cathode/anode finds itself in an environment where electrons/holes are abundant. Likewise, reducing/oxidizing chemicals must be used at a sufficiently high concentration to be active, and again the radical ions are formed in an environment where a
Photoionisation of the tropyl radical
Beilstein J. Org. Chem. 2013, 9, 681–688, doi:10.3762/bjoc.9.77
- threshold photoelectrons by detecting them in coincidence with ions. The spectrometer is a combination of a Wiley–McLaren time-of-flight (TOF) mass spectrometer [48] and a velocity map imaging setup [49]. The latter is equipped with a position sensitive detector with a delay line anode (Roentdek DLD40
Other Beilstein-Institut Open Science Activities
