High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• -donor– π-bridge-acceptor (A–π-D–π-A) electron donor molecules. Based on the known benzodithiophene-terthiophene-rhodanine (BTR) material, the BXR series of materials, BMR (X = M, monothiophene), BBR (X = B, bithiophene), known BTR (X = T, terthiophene), BQR (X = Q, quaterthiophene), and BPR (X = P(penta

• to the SVA devices indicates that further optimization may be required. It is evident that modification of the chromophore length has a large impact on the device stability and performance. BQR as a molecular electron donor is the stand-out performer with the best initial results under all device

• devices optimization is still required. The performance of BQR as a molecular electron donor and the stability of BQR containing BHJ devices encouraged the examination of BQR in ternary BHJ devices. It has been reported that addition of a small percentage of a molecular electron donor to polymer:fullerene

Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties

• Pierre Boufflet,
• Sebastian Wood,
• Jessica Wade,
• Zhuping Fei,
• Ji-Seon Kim and
• Martin Heeney

Beilstein J. Org. Chem. 2016, 12, 2150–2163, doi:10.3762/bjoc.12.205

• -scale is of particular interest in the field of organic photovoltaics (OPV), where separation of the electron donor and acceptor domains on the order of the exciton diffusion length (5–10 nm) is required [1][6][7][8][9]. Many approaches have been reported to tether two or more light-absorbing polymers

The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

• Faith M. Akwi and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 1987–2004, doi:10.3762/bjoc.12.186

• with an increase in electron donor strength of the coupling compound. This method eliminates the use of alkaline and acidic solutions (Scheme 1). In another method developed by Rahimizadeh et al., ferric hydrogen sulfate was used as a catalyst to synthesize azo compounds from aromatic amines and 2

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

• configuration using P3HT as the electron donor. The best results obtained so far are reported in Table 3. For comparison, we also included results for a typical P3HT:PCBM solar cell. First, we note that best PCEs for Zn(WS3)2 are lower than in our previous publication, 2.36% instead of 4.10% [10]. The main

Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes

• Michael Nonnenmacher,
• Dominik M. Buck and
• Doris Kunz

Beilstein J. Org. Chem. 2016, 12, 1884–1896, doi:10.3762/bjoc.12.178

• character than that of typical unsaturated NHCs is expected. However, the IR stretching frequencies of their Rh(CO)2Cl complexes suggest an electron-donor character even stronger than that of saturated NHCs. We ascribe this to the extremely weak π-acceptor character of the dipyrido-annelated NHCs caused by

• ; electron donor character; N-heterocyclic carbene; rhodium; Introduction N-Heterocyclic carbenes form a ligand class that is typically characterized by a strong σ-donor and a weak or even negligible π-acceptor effect [1][2][3], although Meyer has shown pronounced π-acceptor ability in Cu complexes [4][5][6

• -conjugated 14 πe− system into which the “empty” pπ-orbital of the carbene is embedded and therefore, could also act as a π-electron donor. To obtain further experimental evidence for this unusually weak π-acceptor (or already weak π-donor character), we determined the 77Se NMR chemical shift of the

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• suitability of general structure 1 as an electron donor for the design of charge transfer fluorophores. Finally, crystallographic analysis of the boronic esters 29 and 30 highlighted a subtle flattening of the DHQ structure when compared to the saturated THQ; a structural characteristic that was found to

• cause fluorescence in 30, indicating that the DHQ may be a more effective electron donor than the THQ. We are currently utilising the optimised syntheses of these interesting compounds in a range of novel fluorophores, and their applications will be communicated in due course. Experimental Synthetic

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

• introducing conjugated moieties at the 4′-position [10][11][12]. In this context, the synthesis of tailored terpyridine derivatives with appropriate electron-donor/acceptor moieties may allow for a further improvement of their spectroscopic and electrochemical properties. Owing to its unique fluorescent and

Effect of the π-conjugation length on the properties and photovoltaic performance of A–π–D–π–A type oligothiophenes with a 4,8-bis(thienyl)benzo[1,2-b:4,5-b′]dithiophene core

• Ni Yin,
• Lilei Wang,
• Yi Lin,
• Jinduo Yi,
• Lingpeng Yan,
• Junyan Dou,
• Hai-Bo Yang,
• Xin Zhao and
• Chang-Qi Ma

Beilstein J. Org. Chem. 2016, 12, 1788–1797, doi:10.3762/bjoc.12.169

• levels increased (from −5.68 to −5.34 eV) with the increase of the length of the π-conjugated bridge. Organic solar cells using the synthesized compounds as the electron donor and PC61BM as the electron acceptor were fabricated and tested. Results showed that compounds with longer oligothiophene π

• for constructing high-performance A–π–D–π–A-type organic semiconductors for organic solar cells, where A represents the terminal electron acceptor unit, D represents the core electron donor unit, and π represents the conjugated π-bridge [13][14], and a maximum PCE of 9.95% was reported for a

• . Organic solar cells based these conjugated small molecules as the electron donor were fabricated and tested. In addition, long-term stability of these solar cells was also studied, and a general structure–property–performance relationship of these type of molecules is evaluated, which could serve as a

Synthesis and characterization of benzodithiophene and benzotriazole-based polymers for photovoltaic applications

• Desta Gedefaw,
• Marta Tessarolo,
• Margherita Bolognesi,
• Mario Prosa,
• Renee Kroon,
• Wenliu Zhuang,
• Patrik Henriksson,
• Kim Bini,
• Ergang Wang,
• Michele Muccini,
• Mirko Seri and
• Mats R. Andersson

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

• alkylthiophene side chains on the properties of the resulting pristine and blended films are collected and discussed. Solution-processed BHJ PSCs using PTzBDT-1 or PTzBDT-2 as electron-donor materials and PC61BM as electron-acceptor counterpart were fabricated, optimized, and fully characterized. PCEs of 3.3

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

• Hideaki Komiyama,
• Chihaya Adachi and
• Takuma Yasuda

Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142

• LUMO energy levels were calculated to be –3.72 and –3.75 eV for TTA-DPP4 and TTA-DPP2, respectively. Because of their deep-lying HOMO levels and sufficient LUMO offsets (>0.5 eV), both TTA-DPP4 and TTA-DPP2 can serve as electron-donor materials in combination with [6,6]-phenyl-C71-butyric acid methyl

• ester (PC71BM) as an acceptor materials, which has a LUMO level of –4.3 eV. Photovoltaic properties The photovoltaic properties of TTA-DPP4 and TTA-DPP2 were also evaluated. BHJ-OSCs were fabricated using TTA-DPP4 and TTA-DPP2 as electron-donor materials and PC71BM as an electron-acceptor material, with

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• intramolecular C–H bond insertions to form monocyclic and fused bicyclic rings [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59]. The stronger the electron donor, the greater the observed insertion at the C–H bond on the carbon with that donor. For example

Separation and identification of indene–C₇₀ bisadduct isomers

• Bolong Zhang,
• Jegadesan Subbiah,
• David J. Jones and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2016, 12, 903–911, doi:10.3762/bjoc.12.88

• a number of advantages, such as lightweight flexible devices and low-cost fabrication using roll-to-roll printing [1]. Bulk-heterojunction organic solar cells (BHJ OSC) are a specific type of OSCs which contain a blend of organic electron donor and acceptor materials as the photoactive component

• increasing crystallinity of IC70BA can improve the charge carrier mobility of the bulk material but the miscibility with the P3HT electron donor material can also change. A key feature of efficient BHJ solar cell devices is the nanoscale phase separation of the electron donor and acceptor materials into

• electron donor and an electron acceptor) with the film nanostructure being extremely important for the device performance. Molecular structure of IC60BA and IC70BA. a) Schlegel diagram of C70; b) illustrations of three regioisomers of IC70BA and their geometrical isomers. Chromatograms of IC70BA mixture

Self and directed assembly: people and molecules

• Tony D. James

Beilstein J. Org. Chem. 2016, 12, 391–405, doi:10.3762/bjoc.12.42

• collaborate and in particular we worked together to improve the chiral discriminating systems. In order to improve the chiral systems we designed sensors using a d-PET rather than the normal a-PET fluorescence sensing mechanism. With d-PET systems the fluorophore is the electron donor and the protonated amine

• for acidic guests such as tartaric acid and sugar acids [62][63][64][65] (Figure 11). The best chiral discriminating d-PET system was constructed using a phenothiazine fluorophore 17 and 18 [66]. The phenothiazine fluorophore was chosen because it is a very strong electron donor. These sensors

Rhodium, iridium and nickel complexes with a 1,3,5-triphenylbenzene tris-MIC ligand. Study of the electronic properties and catalytic activities

• Carmen Mejuto,
• Beatriz Royo,
• Gregorio Guisado-Barrios and
• Eduardo Peris

Beilstein J. Org. Chem. 2015, 11, 2584–2590, doi:10.3762/bjoc.11.278

• which the reported TEP was 2045 cm−1, therefore suggesting that the tris-MIC ligand B is a stronger electron donor than ligand A. However, this comparison must be taken with care, because the tris-carbene ligands A and B, not only differ in the nature of their carbenes (MIC vs NHC), but also in their

• -Ir(I) complex. Both techniques indicate that the ligand is a stronger electron donor than its related tris-NHC analogue. It is even more important to mention that the tris-MIC ligand is a stronger electron donor than its more closely related mono-MIC ligand – a situation that is also true for the

Biocatalysis for the application of CO₂ as a chemical feedstock

• Apostolos Alissandratos and
• Christopher J. Easton

Beilstein J. Org. Chem. 2015, 11, 2370–2387, doi:10.3762/bjoc.11.259

• -potential electron donor ferredoxin [26], with a requirement for strict anaerobicity, thus limiting the distribution of the reductive TCA cycle. As detailed in Scheme 2, the reductive TCA cycle contains three CO2 fixation steps [24]. Succinyl-CoA (5) is carboxylated by ferredoxin-dependent 2-oxoglutarate

• utilise H2 as an electron donor for the reduction of CO2 [118]. Furthermore, there is a growing list of examples of non-acetogenic metallo-FDHs, naturally catalysing formate oxidation, found to also be capable of catalysing CO2 reduction in vitro. FDH from Pseudomonas oxalaticus was the first isolated

• the visible spectrum (>1.35 eV) and coupled to FDH activity through a mediator to drive CO2 reduction. Two W-dependent FDHs, isolated from the syntrophic bacterium Syntrophobacter fumaroxidans, showed high catalytic activity for CO2 reduction, using reduced methyl viologen as the electron donor. Later

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

• corresponding ground state species. The reaction between photochemically generated radical cations and radical anions by electron transfer from photoexcited electron donor to electron acceptors is often reversible [37] thus reproducing the reactant pair without the formation of a chemical bond. As the dioxygen

Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case

• Karina Mroczyńska,
• Małgorzata Kaczorowska,
• Erkki Kolehmainen,
• Ireneusz Grubecki,
• Marek Pietrzak and
• Borys Ośmiałowski

Beilstein J. Org. Chem. 2015, 11, 2105–2116, doi:10.3762/bjoc.11.227

• complexes The VT 1H NMR experiments were conducted to have a deeper insight into the nature of the rotameric equilibrium within the complexes. The following salts were chosen (at various [1]:[benzoate] ratios [1] = 18.9 mmol dm−3): a) unsubstituted 5 (R = H), b) carrying electron donor 2 (R = NMe2) and c

Profluorescent substrates for the screening of olefin metathesis catalysts

• Raphael Reuter and
• Thomas R. Ward

Beilstein J. Org. Chem. 2015, 11, 1886–1892, doi:10.3762/bjoc.11.203

• (umbelliferone) (9) upon ring-closing metathesis. The synthesis of coumarin derivatives using this approach was described in previous publications [20][21]. By introducing an electron donor in the 7-position, a fluorescent product is obtained upon ring-closing metathesis [22]. Synthesis of the profluorescent

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

• ) electron donor and polythiophene (PT) conjugated systems are highly popular classes of organic compounds which have shown fascinating conducting and electronic properties. The advantages of PT-based materials are their synthetic versatility, excellent film-forming properties and potential to increase the

• dithienyl-thieno-TTF unit and the localised nature of the LUMO led to donor–acceptor interactions in the solid phase, making it impossible for efficient overlap between LUMOs, which would normally be required for an efficient n-type semiconductor. BHJSCs were fabricated from 48 as the electron donor and

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• based on the conjugation of an acylated sylibin derivative (19) with L-ascorbic acid (20), tyrosol (21) and trolox alcohol (22) (Scheme 4) [44]. These compounds proved to have excellent electron donor, antiradical, antioxidant as well as cytoprotective abilities. Moreover, in a different research area

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• where the electron can reduce an electron acceptor with a suitable redox potential to a radical anion (A–•) and/or the hole can oxidize an electron donor to the radical cation (D+•, Figure 1). Recombination, whereby the electron drops back down to the VB, occurs in competition with this in the bulk of

• a reaction partner because on photoactivation it supplies electrons and holes while also donating protons from surface hydroxy groups. An interesting adjunct to these results was our finding that aryloxy-, arylthio- and anilino-acetic acids, carrying electron donor substituents (2-, 3- or 4-MeO, t

• transformations an excess of a sacrificial electron donor (reductive quencher) is needed to scavenge the VB holes and prevent e−/h+ recombination. Alcohols and amines have been successfully deployed in this role. Reductions of nitroaromatics took place effectively in photoactivated aqueous TiO2 slurries, with

Synthesis of racemic and chiral BEDT-TTF derivatives possessing hydroxy groups and their achiral and chiral charge transfer complexes

• Sara J. Krivickas,
• Chiho Hashimoto,
• Junya Yoshida,
• Akira Ueda,
• Kazuyuki Takahashi,
• John D. Wallis and
• Hatsumi Mori

Beilstein J. Org. Chem. 2015, 11, 1561–1569, doi:10.3762/bjoc.11.172

• chiral salt α’-[(S,S)-2]ClO4 without H2O, but has a similar donor arrangement. According to the molecular design by introduction of hydroxy groups and a ClO4− anion, many intermediate-strength intermolecular hydrogen bonds (2.6–3.0 Å) were observed in these crystals between electron donor molecules

• ][17], ethylenedioxy [18], and pyrazino [19]), due to the difficulty of chiral-crystal growth. In order to improve the crystallinity, the inclusion of hydroxy groups in the BEDT-TTF molecule has been postulated to produce hydrogen bonding interactions between electron-donor molecules, electron-acceptor

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• tetrafluoroborates showing that both electron-donor and electron-acceptor substituted phenyldiazonium tetrafluoroborates undergo efficient borylation with an equimolar amount of B2pin2 (Scheme 1); however, ortho-substituted phenyldiazonium salts were found to be either not efficient substrates (3f) or completely

• , iodination with I2 shows a higher sensitivity to electronic properties of substituents on the aromatic ring. Electron-acceptor substituted aryldiazonium compounds are excellent substrates while those with electron-donor groups react much less efficiently. The substitution of pyridine with collidine (2,4,6

• electron-donor or acceptor groups while ortho-substituted substrates are less reactive. A mechanism involving aryl radicals is suggested. The Suzuki–Miyaura reaction of SF5-phenylboronates with aryl iodides provided the cross-coupling biaryl products. In analogy to the borylation reaction, iodination of

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

• for various applications. They have been, for example, used as electron donor molecules to prepare electrically (super)conducting crystalline materials [4][5][6][7], as solar energy systems [8][9] or even as donor moieties in nonlinear optical (NLO) materials [10][11]. In the last decades one 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

• Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark 10.3762/bjoc.11.125 Abstract The electron-donor and unique redox properties of the tetrathiafulvalene (TTF, 1) moiety have led to diverse applications in many areas of chemistry. Monopyrrolotetrathiafulvalenes (MPTTFs, 4) and

• molecular machines [1][2][3][4][5], molecular and organic electronics [5][6][7], chemosensors [1][8][9][10][11], coordination chemistry [12][13][14], catalysis [15] and beyond [16][17][18][19][20][21]. This owes much to the strong electron-donor character of the TTF moiety and its derivatives, which have

• 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