Thiophene-forming one-pot synthesis of three thienyl-bridged oligophenothiazines and their electronic properties

• Dominik Urselmann,
• Konstantin Deilhof,
• Bernhard Mayer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2016, 12, 2055–2064, doi:10.3762/bjoc.12.194

• electronics [37][38][39][40]. In comparison to thiophene, phenothiazine, a tricyclic dibenzo-1,4-thiazine, possesses a significantly lower oxidation potential, similar to aniline. However, phenothiazine derivatives form stable deeply colored radical cations with perfect Nernstian reversibility [41][42][43][44

• involved. Electronic spectra and oxidation potentials The electronic properties of the three thienyl-bridged oligophenothiazines 3 were experimentally investigated by absorption and emission spectroscopy and by cyclic voltammetry (Table 1). Cyclic voltammetry discloses the oxidation potential as an

• electronic communication between both electrophore moieties. The first oxidation potential of 2,5-bis(diphenothiazinyl)thiophene 3b is cathodically shifted and appears at a peak potential of E1/2 = 620 mV, however, without displaying Nernstian behavior (Figure 2, center). Two further oxidation waves can be

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• addition of fluorine [13]. The second oxidation potential for all zinc(II) chelates, 0.77–0.79 V, showed little change except in two cases: Zn(L4)2 and Zn(L2)2 had second oxidation potentials of 0.84 V and 0.73 V, respectively. The differences between the first and second oxidation potential was 0.27 V for

• Zn(WS3)2, while it was 0.18 V and 0.19 V for Zn(L1)2 and Zn(L2)2, respectively. For both Zn(L3)2 and Zn(L4)2 the difference between oxidation potentials was 0.23 V, a slight decrease from Zn(WS3)2 at 0.27 V. All of the fluorinated zinc(II) complexes exhibit a rise of the first oxidation potential as

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• , the more anodic peak was tentatively assigned to the formation of the cation radical of the azulene moiety. The DPV experiments confirmed that stabilization of the tropylium cation in the case of 4b, the oxidation potential being shifted anodically at 0.70 V as compared to 0.56 V for 4a (Figure 7

3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic–organic hybrid perovskite solar cells

• Wei Li,
• Munechika Otsuka,
• Takehito Kato,
• Yang Wang,
• Takehiko Mori and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2016, 12, 1401–1409, doi:10.3762/bjoc.12.134

• oxidation peaks in the measurement range (Figure 1b). 3,6-Cbz-EDOT exhibited the onset oxidation potential (Eox,onset) at 0.38 V (vs Ag/Ag+), whereas the Eox,onset of 2,7-Cbz-EDOT was slightly higher (0.50 V). This difference can also be explained by the different connectivity pattern between the two

Syntheses of dibenzo[d,d']benzo[2,1-b:3,4-b']difuran derivatives and their application to organic field-effect transistors

• Minh Anh Truong and
• Koji Nakano

Beilstein J. Org. Chem. 2016, 12, 805–812, doi:10.3762/bjoc.12.79

• showed one oxidation wave with an onset potential of 0.56 eV (vs Fc/Fc+, HOMO = −5.36 eV). The lower oxidation potential and higher HOMO energy level of syn-DNBDF 6 should reflect its longer π-conjugation length than syn-DBBDF 5. Based on their HOMO energy levels and HOMO−LUMO energy gaps, syn-DBBDF 5

Study on the synthesis of the cyclopenta[f]indole core of raputindole A

• Nils Marsch,
• Mario Kock and
• Thomas Lindel

Beilstein J. Org. Chem. 2016, 12, 334–342, doi:10.3762/bjoc.12.36

• PMB group, because the oxidation potential of DMB ethers is lower and the cleavage was expected to be more facile [45]. Indole synthesis from DMB-protected 13 and subsequent Boc protection afforded 16 (58%). Alkynylation and desilylation of 16 to 19 and coupling of 19 with ketone 6 proceeded smoothly

Photoinduced 1,2,3,4-tetrahydropyridine ring conversions

• Baiba Turovska,
• Henning Lund,
• Viesturs Lūsis,
• Anna Lielpētere,
• Edvards Liepiņš,
• Sergejs Beljakovs,
• Inguna Goba and
• Jānis Stradiņš

Beilstein J. Org. Chem. 2015, 11, 2166–2170, doi:10.3762/bjoc.11.234

• difference between the first oxidation potential of the donor and the first reduction potential of the acceptor; In CH2Cl2 the reduction potential of O2 is −1.18 V and E0 of 1 is +1.14 V. The reaction becomes thermodynamically favourable if the organic molecule is excited to a singlet state. The oxidation

• potential of excited molecules is shifted to negative values (ΔE = ~2 V) compared to their ground state [21][22][23]. For example the oxidation potential of 9,10-dihydro-10-methylacridine is +0.80 V [23], which is shifted to −3.10 V in the singlet excited state [23]. The recorded UV–vis spectrum of 1

A new approach to ferrocene derived alkenes via copper-catalyzed olefination

• Vasily M. Muzalevskiy,
• Aleksei V. Shastin,
• Alexandra D. Demidovich,
• Namiq G. Shikhaliev,
• Abel M. Magerramov,
• Victor N. Khrustalev,
• Rustem D. Rakhimov,
• Sergey Z. Vatsadze and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2015, 11, 2072–2078, doi:10.3762/bjoc.11.223

• intermediates in the synthesis of ferrocene analogs of tamoxifen and other medicinally relevant molecules. Electrochemical properties of halovinylferrocenes The ferrocene unit possesses several exciting electrochemical characteristics, such as fast electron-transfer rate, low oxidation potential, and stability

• . The values of the respective oxidation potential depend mainly on the amount of the vinyl groups attached to the ferrocene core. There is also the effect of the halogen atom, though to a lesser extent compared to the effect of the amount of vinyl groups. For example, all dichloro and dibromo compounds

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• oxidation potential of TTF and that of the thiophene backbone of the monomer, the TTF-modified bithiophene compounds 5b–d were used as monomers for electropolymerisation to 6b–d [49]. The appearance of an additional, well-defined oxidation wave in the CV, as the first oxidation wave was split in both anodic

• ]. Polymers with fused TTF units The electronic characterisation for monomer units 14a–c and 28a is shown in Table 1. Electropolymerisation of monomer compounds 14a, 14c and 28a [73] was attempted. Due to the high oxidation potential (see Table 1) of the thiophene unit in the fused system 14a (2.18 V vs Ag

• polaron charge carrier route; 3) the oxidation potential of the polymer backbone is likely to be in the same region as the potential for TTF2+ formation, although the contribution to the current from the normally irreversible oxidation of the PT backbone would be small due to the high TTF content in the

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly

• Masahiko Iyoda and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2015, 11, 1596–1613, doi:10.3762/bjoc.11.175

• CH2Cl2 based on the high HOMO levels of TTF units. Another important feature in the CV data of 28–32 is broadening or splitting of the first oxidation wave, indicating intra- and/or intermolecular interactions between TTF units [68]. Interestingly, the first oxidation potential of 28 and 29 splited at

• the slow scanning rate of 3 mV s−1 owing to the intermolecular mixed-valence interaction between the TTF•+ and TTF moieties under diffusion-controlled conditions. In the case of 31, the first oxidation potential (E1/2 = 0.14 V vs Fc/Fc+) is lower than that of 32 with alkyl groups (E1/2 = 0.20 V

• ). Since the first oxidation potential of 31 in a dilute solution broadened but did not split (E1/2ox1 in CH2Cl2: 0.23 (3e) V), the potential of 31 at 0.14 V (Table 4) reflected the strong intermolecular interaction between the TTF•+ and TTF moieties in 31•+. By comparison with the known UV–vis/NIR spectra

Tetrathiafulvalene-based azine ligands for anion and metal cation coordination

• Awatef Ayadi,
• Aziz El Alamy,
• Olivier Alévêque,
• Magali Allain,
• Nabil Zouari,
• Mohammed Bouachrine and
• Abdelkrim El-Ghayoury

Beilstein J. Org. Chem. 2015, 11, 1379–1391, doi:10.3762/bjoc.11.149

• the second cycle a negligible change of the oxidation potential of the ligand which is very likely because of the large distance between the TTF and the fluoride coordinating unit (Figure S8 in Supporting Information File 1). In order to get further supports to the observed optical sensing and to get

• ). This increase of the oxidation potential suggests that the rhenium fragment is acting as an electron acceptor by decreasing the electron density on the TTF unit. This behavior is in agreement with the electronic absorption experiments and confirms the strong electronic conjugation in ligand L2. The

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131

• expected to have a higher oxidation potential than DMF due to the nitro group the advantageous use of an undivided cell appears to be possible. Taking the optimal conditions of electrolysis Nr. 5 in Table 1 the influence of the parameters mentioned above was investigated (Table 2). The influence of the

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• thermodynamically stable. These properties are responsible for the strong electron-donor character of TTF and its derivatives. Furthermore, the precise oxidation potential of a TTF derivative can be changed by the addition of electron-donating or electron-withdrawing substituents [4]. Usually, each of the three

Regioselective synthesis of chiral dimethyl-bis(ethylenedithio)tetrathiafulvalene sulfones

• Flavia Pop and
• Narcis Avarvari

Beilstein J. Org. Chem. 2015, 11, 1105–1111, doi:10.3762/bjoc.11.124

• to transform into BEDT-TTF. Moreover, since the inner sulfur atoms present large orbital coefficients in the HOMO, the introduction of the electron-withdrawing oxygen atom induces a massive increase of the oxidation potential from the neutral to the radical cation states. We have then hypothesized

• that the oxidation of the outer sulfur atoms into sulfoxide or sulfone should only moderately influence the oxidation potential and thus provide more stable radical cation species. In order to access chiral precursors with controlled stereochemistry we decided to investigate the sulfoxidation of the DM

Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F₄TCNQ

• Raúl García,
• M. Ángeles Herranz,
• Edmund Leary,
• M. Teresa González,
• Gabino Rubio Bollinger,
• Marius Bürkle,
• Linda A. Zotti,
• Yoshihiro Asai,
• Fabian Pauly,
• Juan Carlos Cuevas,
• Nicolás Agraït and
• Nazario Martín

Beilstein J. Org. Chem. 2015, 11, 1068–1078, doi:10.3762/bjoc.11.120

• argon atmosphere and at a scan rate of 0.1 Vs−1. The electrochemical cell consisted of a glassy carbon working electrode, Ag/AgNO3 reference electrode and a Pt wire counter electrode. It is worth mentioning that ferrocene was not employed as the inner reference since its oxidation potential overlaps

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• clip 4 is an efficient receptor for F4-TCNQ guest electron acceptor. This difference in binding interaction between host molecular clips 3 and 4 towards the F4-TCNQ guest could be explained by their electrochemical properties. By comparing the first oxidation potential of clips 3 and 4 with the first

• guest. On the other hand, the oxidation potential of molecular clip 4 is increased due to the introduction of the naphthoquinone spacer. Consequently, the corresponding 1:1 stoichiometry should reasonably correspond to the binding of F4-TCNQ inside the cavity of clip 4 (Figure 11). This binding of F4

Tuning of tetrathiafulvalene properties: versatile synthesis of N-arylated monopyrrolotetrathiafulvalenes via Ullmann-type coupling reactions

• Vladimir A. Azov,
• Diana Janott,
• Dirk Schlüter and
• Matthias Zeller

Beilstein J. Org. Chem. 2015, 11, 860–868, doi:10.3762/bjoc.11.96

• processes in molecular and supramolecular systems [3][4]. Availability of selective synthetic methods [5][6] gave access to differently substituted tetrathiafulvalene (TTF) moieties which allowed tuning of oxidation potential, donating ability, as well as other physical and chemical properties. The

• the second to the dication. Non-substituted derivative 4c shows a lower first oxidation potential than its alkylS-substituted counterpart 4a,b, as expected due to the electron-withdrawing effect of the two thioalkyl groups [28][29]. The strong electron-withdrawing effect of the 4-nitrophenyl group in

• 4d manifests itself in an increased oxidation potential with a shift of ca. 0.08 V for both oxidation waves. Aromatic electron-donating groups as in 4e and 4f do barely influence the potential of the two oxidation waves. Instead, they induce an additional oxidation wave at higher potentials of 1.06 V

Trifluoromethyl-substituted tetrathiafulvalenes

• Olivier Jeannin,
• Frédéric Barrière and
• Marc Fourmigué

Beilstein J. Org. Chem. 2015, 11, 647–658, doi:10.3762/bjoc.11.73

• . Electrochemical data confirm the good correlations between the first oxidation potential of the TTF derivatives and the σmeta Hammet parameter, thus in the order CO2Me < CF3 < CN, indicating that, in any case, the mesomeric effect of the substituents is limited. Besides, crystal structure determinations show that

• tetrathiafulvalenes functionalized by electron-withdrawing groups (EWG) are less documented, essentially because the presence of such substituents as halogen, acyl, ester, amide or nitrile on the TTF redox core dramatically increases its oxidation potential and destabilizes the radical cation form. This strong anodic

• moieties and formation of fluorine bilayers [32][33], attributed to the amphiphilic character of those TTF derivatives upon CF3-functionalization. A strong anodic shift of the first oxidation potential was also noted for 1c and 2cc, when compared with the unsubstituted EDT-TTF molecule. This work has been

Photocatalytic nucleophilic addition of alcohols to styrenes in Markovnikov and anti-Markovnikov orientation

• Martin Weiser,
• Sergej Hermann,
• Alexander Penner and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2015, 11, 568–575, doi:10.3762/bjoc.11.62

• oxidation potential of 2.07 V. In combination with the oxidation potential of 1.81 V (vs SCE) [22] for substrate 1 the driving force ΔG of initial oxidation was estimated by Rehm–Weller to be around 250 meV. In general, irradiations were carried out in quartz glass cuvettes at a constant temperature of 30

• of phenol, weakened the nucleophilicity for this type of reaction. Styrene (6) has an oxidation potential of 1.94 V (vs SCE) [22] and, hence, could also be oxidized by the chosen photocatalyst PDI. The corresponding photocatalytic nucleophilic additions to 6 (Table 1) yielded less of each product

• , which was in agreement with the higher oxidation potential (compared to 1). Here again, the addition of phenol showed no significant amounts of product formation. We representatively demonstrated the dependency of the performance of photocatalysis with substrate 1 on different PDI concentrations (Figure

Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

• Erdal Ertas,
• İlknur Demirtas and
• Turan Ozturk

Beilstein J. Org. Chem. 2015, 11, 403–415, doi:10.3762/bjoc.11.46

• coupling methods [45][46]. Depending on the presence of electron-withdrawing groups on the TTF, they exhibit various oxidation potential ranges [15][26]. Recently, TTF and analogues have received widespread attention involving the development of new materials by using various anions to form different

• were performed under a nitrogen atmosphere at room temperature using Pt as working and counter electrodes and Ag/AgCl reference electrode. The oxidation potentials of the coupled products were compared with ET 3. The measurements indicated that as the first oxidation potential of ET was higher than the

• first oxidation potential of 29a, 29c and 29d, the oxidation potential of 29b was equal to that of ET 3 and the second oxidation potentials of 29a–d were found to be lower than for ET. On the other hand, the first and second oxidation potentials of the donors 33a–c were slightly higher than the

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• cholesterol oxidation products are rather low, often less than 30%. This may be caused by the high oxidation potential of cholesterol and the necessity to operate at a relatively high positive potential. Moreover, due to the hydrophobic properties of cholesterol it is necessary to use non-polar solvents, e.g

Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions

• Bichlien H. Nguyen,
• Robert J. Perkins,
• Jake A. Smith and
• Kevin D. Moeller

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

• oxidants [5]. In such experiments, the potential at the anode increases to a point where it matches the oxidation potential of the reduced chemical oxidant (Scheme 1). The reduced chemical oxidant is then oxidized in order to generate the active chemical oxidant. The chemical oxidant then performs the

• photovoltaic cell exposed to the light until the current passing through the reaction was the same as that used with the traditional setup. The two cases in Scheme 2 were selected because the oxidation potential of the substrates differed by more than 0.5 V. However, that difference in potential had little

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• phenoxy radical formed can be further oxidized to the phenoxenium ion, which reacts with nucleophiles. However, since the phenolic OH group is not sterically shielded here, competitive oligo- and polymerization reactions may also occur. Therefore, despite the low oxidation potential of 6g, the side

Highly selective electrochemical fluorination of dithioacetal derivatives bearing electron-withdrawing substituents at the position α to the sulfur atom using poly(HF) salts

• Bin Yin,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2015, 11, 85–91, doi:10.3762/bjoc.11.12

• higher oxidation potential of 2h compared to that of the starting substrate 1h. In support of this, we have already shown that introduction of one fluorine atom to the α-position of α-(phenylthio)acetonitrile increased the oxidation potential by 0.36 V [22]. A plausible mechanism for the anodic

Redox active dendronized polystyrenes equipped with peripheral triarylamines

• Toshiki Nokami,
• Naoki Musya,
• Tatsuya Morofuji,
• Keiji Takeda,
• Masahiro Takumi,
• Akihiro Shimizu and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2014, 10, 3097–3103, doi:10.3762/bjoc.10.326

•  2. Di(p-bromophenyl)carbinol (1) was treated with SOCl2 to obtain di(p-bromophenyl)methyl chloride (2) in quantitative yield. A Friedel–Crafts-type alkylation [29] of diphenylsilane 3 with 2 in the presence of boron trifluoride etherate as a Lewis acid gave 4 in 86% yield. The oxidation potential of

• than the oxidation potential of dendrimer 4, indicating that the triarylamine moiety is oxidized before the benzylsilane moiety. Using the “graft to” approach to synthesize peripherally functionalized dendronized polystyrene (Figure 1b) employing 5 as a precursor of the dendritic carbocation was

• . A saturated calomel electrode (SCE) (RE-2B, ALS Co. Ltd.) was used as the reference electrode. The oxidation potential (Eox) of dendrimer 4 was measured using linear sweep voltammetry employing a gassy carbon (GC) rotating disk electrode (diameter = 3.0 mm, ALS Co. Ltd.) and a Pt wire counter