An organocatalytic route to 2-heteroarylmethylene decorated N-arylpyrroles

• Alexandre Jean,
• Jérôme Blanchet,
• Jacques Rouden,
• Jacques Maddaluno and
• Michaël De Paolis

Beilstein J. Org. Chem. 2013, 9, 1480–1486, doi:10.3762/bjoc.9.168

• preparation of N-arylpyrroles is an active field of investigation [5]. Depending on their substituents, N-arylpyrroles could also be electron donor/acceptor molecules with a dual fluorescence ability suggesting attractive optoelectronic applications [6][7]. If the N-arylation of pyrroles is possible by

• ideal for the preparation of electron donor/acceptor N-arylpyrroles as demonstrated in this study. In addition, we documented an efficient C–H oxidation of the bis(heteroaryl)methylene position promoted by CAN. Experimental General: 1H and 13C NMR spectra were recorded in deuterated chloroform on Bruker

True and masked three-coordinate T-shaped platinum(II) intermediates

• Manuel A. Ortuño,
• Salvador Conejero and
• Agustí Lledós

Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153

• blocked somehow to prevent undesirable contacts, and in most cases, bulky ligands are required to protect the empty coordination site. Strong electron-donor ligands also help stabilizing the formally 14-electron compounds. It is worthy of note that almost all of them are cationic. The first true T-shaped

Efficient Cu-catalyzed base-free C–S coupling under conventional and microwave heating. A simple access to S-heterocycles and sulfides

• Silvia M. Soria-Castro and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2013, 9, 467–475, doi:10.3762/bjoc.9.50

• . Electron-donor and electron-acceptor substituents are tolerated, and polysubstitution can also be successfully accomplished. Experimental Representative experimental procedures for the Cu-catalyzed base-free C–S coupling Method A: The reactions were carried out in a 10 mL two-necked Schlenk tube, equipped

Synthesis of SF₅-containing benzisoxazoles, quinolines, and quinazolines by the Davis reaction of nitro-(pentafluorosulfanyl)benzenes

• Petr Beier and
• Tereza Pastýříková

Beilstein J. Org. Chem. 2013, 9, 411–416, doi:10.3762/bjoc.9.43

• arylacetonitriles to provide the SF5-containing benzisoxazoles. Good yields were obtained with arylacetonitriles containing the electron-neutral or electron-donor group, while those with the electron-acceptor group were found to be unreactive. Reductions of the benzisoxazoles gave ortho-aminobenzophenones in high

• with electron-donor groups were found to be unreactive [7]. Addition of 1.5 equiv of 6a and 3 to a solution of 10 equiv NaOH in ethanol produced a deep red–brown reaction mixture with the formation of a brown precipitate after a few minutes of stirring. After a further 15–30 minutes the precipitate

• amount of base and 6 were varied. Next, an investigation of the scope of the reaction was carried out. The presence of electron-donor groups on the benzene ring of 6 gave good yields of benzisoxazoles 7; however, the reaction with (4-chlorophenyl)acetonitrile (6b) provided only traces of 7b (no

Highly selective synthesis of (E)-alkenyl-(pentafluorosulfanyl)benzenes through Horner–Wadsworth–Emmons reaction

• George Iakobson and
• Petr Beier

Beilstein J. Org. Chem. 2012, 8, 1185–1190, doi:10.3762/bjoc.8.131

• unavailable, and the reaction in ortho-positions would give too strained a product. The formation of the cyclized side product is not restricted to compounds with an electron-donor substituent on the aromatic ring. Similarly to 8d, the cyclic product was detected by GCMS in diazotization of compound 8c

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• type (o- or p-(X)–C6H4–N=N–Ar): The π→π* and n→π* bands are very close or collapsing in the UV–vis region. In this case, the azocompounds have electron-donor substituents (X) in the ortho or para positions (orange colour). Pseudo-stilbene type [(X)–C6H4–N=N–C6H4–(Y)]: The absorption band corresponding

• fluorescence emitted by the pyridinium salt free cyclophane. The azobenzene trans-10 is conveniently replaced with electron donor units, so that when it is associated, as azo-10∙11, the fluorescence is completely inhibited by charge-transfer interactions. The photoexcitation carried out by irradiation with

The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

• Renjie Wang,
• Shouzhi Pu,
• Gang Liu and
• Shiqiang Cui

Beilstein J. Org. Chem. 2012, 8, 1018–1026, doi:10.3762/bjoc.8.114

• fatigue resistance and thermal stability [2][36]. In general, the photochromic reactivity of diarylethenes mainly depends on heteroaryl groups and different electron-donor/acceptor substituents. The formyl group can be modified to form various chemical groups and it can also be connected with different

Hybrid super electron donors – preparation and reactivity

• Jean Garnier,
• Douglas W. Thomson,
• Shengze Zhou,
• Phillip I. Jolly,
• Leonard E. A. Berlouis and
• John A. Murphy

Beilstein J. Org. Chem. 2012, 8, 994–1002, doi:10.3762/bjoc.8.112

• motif, 6, which marks a weaker donor. To extend the capabilities of such reagents, we now set out to design the first neutral, organic ground-state donor that could, at room temperature, reduce aryl iodides to aryl radicals (thereby acting as a single-electron donor) as opposed to aryl anions. Hybrid

• bromide (16) [34] with N-methylimidazole (17) afforded disalt 19. Deprotonation with NaH (15 equiv) in DMF then afforded the electron donor 11 in situ; this was reacted with iodine to afford the oxidised diiodide salt, and this was subjected to anion exchange to afford the bis(hexafluorophosphate) salt 21

• ], and so its capability as an electron donor was tested. To test reactivity, donor 11 was prepared in situ and treated with the substrates 28 and 30 at room temperature (Scheme 2). Simple substrate 28 [35] was added to 11, prepared by adding disalt 19 (1.5 equiv) to excess sodium hydride (15 equiv). As

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

• Stefanie Potratz,
• Amaresh Mishra and
• Peter Bäuerle

Beilstein J. Org. Chem. 2012, 8, 683–692, doi:10.3762/bjoc.8.76

• electronic communication between the chromophores [21][22][23][31]. It has also been shown that a 1,2,3-triazole can act as a strong σ-electron donor [26] or as a weak π-electron acceptor [15]. In this study, we aimed at the combination of electron-rich (oligo)thiophenes as donors and electron-deficient

On the control of secondary carbanion structure utilising ligand effects during directed metallation

• Andrew E. H. Wheatley,
• Jonathan Clayden,
• Ian H. Hillier,
• Alison Campbell Smith,
• Mark A. Vincent,
• Laurence J. Taylor and
• Joanna Haywood

Beilstein J. Org. Chem. 2012, 8, 50–60, doi:10.3762/bjoc.8.5

• ) (for 3-H) [23] or THF (for 4-H) [24] to yield 3/4-Lil·nL (n = 1, L = PMDTA; n = 3, L = THF). Notably, whereas the deptonation of 4-H in the presence of THF yielded the lateral lithiate as a tris(THF) solvate, the tridentate electron donor PMDTA was required to replicate this chemistry with 3-H

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• -IM-(π-A)2 (16), A-π-IM-(π-D)2 (17), A-π-IM-(π-A)2 (18), and D-π-IM-(π-D)2 (19). 4,5-Bis(4-nitrophenyl)imidazole was utilized as a suitable acceptor moiety and was further modified with a thiophene π-linker as an auxiliary electron donor (20). These basic push–pull imidazoles were mainly investigated

• of the π-linker, particularly in chromophores 53–57, caused β enhancement up to 320 × 10−30 esu (Table 8). This clearly demonstrates the beneficial role of the thiophene as a polarizable unit and auxiliary electron donor. A combination of fused phenanthroline-imidazole acceptor moiety, N,N

• interest for materials chemists due to their unique and tunable properties. In general, the imidazole-derived chromophores may possess two Y-shaped arrangements: One electron donor at C2 and two electron acceptors at C4/C5 or vice versa. Hence, according to the C4/C5 substitution, the entire imidazole

Equilibrium constants and protonation site for N-methylbenzenesulfonamides

• José A. Moreira,
• Ana M. Rosa da Costa,
• Luis García-Río and
• Márcia Pessêgo

Beilstein J. Org. Chem. 2011, 7, 1732–1738, doi:10.3762/bjoc.7.203

• -NO2 (3d), in aqueous sulfuric acid were studied at 25 °C by UV–vis spectroscopy. As expected, the values for the acidity constants are highly dependent on the electron-donor character of the substituent (the pKBH+ values are −3.5 ± 0.2, −4.2 ± 0.2, −5.2 ± 0.3 and −6.0 ± 0.3 for 3a, 3b, 3c and 3d

• , respectively). The solvation parameter m* is always higher than 0.5 and points to a decrease in the importance of solvation on the cation stabilization as the electron-donor character of the substituent increases. Hammett plots of the equilibrium constants showed a better correlation with the σ+ substituent

• occurs on the sulfonyl oxygen atom, as such a structure may present resonance with the electron-donor substituents (Scheme 2). The fact that pKBH+ correlates better with σ+ (R = 0.9913) than with σ (R = 0.9681) also indicates protonation on the oxygen atom (Figure 4). Nevertheless, the curvature of the σ

Sexithiophenes as efficient luminescence quenchers of quantum dots

• Christopher R. Mason,
• Yang Li,
• Paul O’Brien,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2011, 7, 1722–1731, doi:10.3762/bjoc.7.202

• perfluoroalkyl groups for n-type semiconductors [12][13]. Previously, we reported the synthesis and properties of alkyl end-capped oligothiophenes 2 (Figure 1), which incorporate the ethylene dithiothiophene (EDTT) unit, including their performance as the electron donor material in a bilayer photovoltaic device

Intramolecular hydroamination of alkynic sulfonamides catalyzed by a gold–triethynylphosphine complex: Construction of azepine frameworks by 7-exo-dig cyclization

• Hideto Ito,
• Tomoya Harada,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2011, 7, 951–959, doi:10.3762/bjoc.7.106

• triethynylphosphine L1 in electron-donor ability [58], was slightly more effective than PPh3, but was far less effective than L1 (Table 1, entry 12). Bulky and strongly electron-donating ligands such as X-Phos and IPr were as effective as the electron-deficient ligand P(OPh)3 (Table 1, entries 13 and 14). Accordingly

Recent advances in the development of alkyne metathesis catalysts

• Xian Wu and
• Matthias Tamm

Beilstein J. Org. Chem. 2011, 7, 82–93, doi:10.3762/bjoc.7.12

• towards early transition metals or metals in a higher oxidation state [53][54][55]. In recent years, our group has significantly expanded the use of these 2σ,4π-electron donor ligands in organometallic chemistry and homogeneous catalysis [56][57][58][59][60][61][62][63][64][65][66][67]. Their synthesis

Backbone tuning in indenylidene–ruthenium complexes bearing an unsaturated N-heterocyclic carbene

• César A. Urbina-Blanco,
• Xavier Bantreil,
• Hervé Clavier,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2010, 6, 1120–1126, doi:10.3762/bjoc.6.128

• complexes [26][27][28][29][30][31][32]. This method was initially developed by Tolman [33], using the average infrared frequency of CO in [Ni(CO)3L] complexes. This electronic parameter has become known as the Tolman electronic parameter (TEP) and has been used to quantify the electron donor ability of

Self-assembly and semiconductivity of an oligothiophene supergelator

• Pampa Pratihar,
• Suhrit Ghosh,
• Vladimir Stepanenko,
• Sameer Patwardhan,
• Ferdinand C. Grozema,
• Laurens D. A. Siebbeles and
• Frank Würthner

Beilstein J. Org. Chem. 2010, 6, 1070–1078, doi:10.3762/bjoc.6.122

• concentration of 5 x 10−5 M. Studies on blends of T1 with PCBM The fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is a well-known n-type semiconductor and its blends with various electron-donor materials have been extensively used in solar cell devices [24]. The morphology of the blend

Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

• Ritesh Nandy and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112

• Ritesh Nandy Sethuraman Sankararaman Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India 10.3762/bjoc.6.112 Abstract Several 2-(phenylethynyl)triphenylene derivatives bearing electron donor and acceptor substituents on the phenyl rings have been synthesized. The

• show that the triphenylene chromophore can act either as an electron donor or as an electron acceptor in the ICT process, depending upon the nature of substituent on the phenyl ring. Derivatives 1e and 1g are potential candidates for use as solvent polarity probes. However, their performance is only

Differences between β-Ala and Gly-Gly in the design of amino acids-based hydrogels

• Andreea Pasc,
• Firmin Obounou Akong,
• Sedat Cosgun and
• Christine Gérardin

Beilstein J. Org. Chem. 2010, 6, 973–977, doi:10.3762/bjoc.6.109

• including, NMR, FT-IR, scanning electron microscopy, SAXS/WAXS. Results and Discussion Molecular design A hydrogelator generally contains three functional domains: a hydrogen or electron donor and acceptor domain as the main organiser, a hydrophilic domain to adjust the solubility in water or in organic

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• visible exhibiting blue or dark green colours, small band gaps and high charge carrier mobilities. They are suitable as electron donor in bulk heterojunction solar cells with PC60BM or PC70BM as electron acceptors to give maximum power conversion efficiencies of about 5%. In field-effect transistors they

Structure and reactivity in neutral organic electron donors derived from 4-dimethylaminopyridine

• Jean Garnier,
• Alan R. Kennedy,
• Leonard E. A. Berlouis,
• Andrew T. Turner and
• John A. Murphy

Beilstein J. Org. Chem. 2010, 6, No. 73, doi:10.3762/bjoc.6.73

• at the 4 and 4′ positions led to only slight changes in the redox potentials. Keywords: dication; 4-DMAP; electron donor; electron transfer; radical cation; redox; reduction; Introduction Neutral organic compounds 1 and 4–10 (Figure 1) have attracted considerable attention as ground-state electron

• the conversion of an aryl radical to an aryl anion [39]. Whatever about the standard potentials, in practice, the formation of aryl anions is only observed when the electron donor has E1/2 = −1 V or is more negative [40]. In line with this, both the imidazole-derived donor 7 (E1/2 = −1.20 V vs SCE in

• the same potential (within 10 mV), so the increased flexibility does not benefit the two-electron donor 15 relative to 8. Taking the idea of flexible rotation between the two halves of the molecule to its limit, we prepared compound 20′ [27] (Figure 5) and determined its cyclic voltammetric behaviour

A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions

• Marc Debeaux,
• Kai Brandhorst,
• Peter G. Jones,
• Henning Hopf,
• Jörg Grunenberg,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2009, 5, No. 31, doi:10.3762/bjoc.5.31

• derivatives have been shown to be efficient emitters for OLED applications [2]. In these devices, the benzanthrone moiety acts as an electron accepting group, whereas the diarylamine group functions as an electron donor. The reaction of 1 with various organometallic reagents was studied by Allen in the 1970s

Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties

• Harald Schmaderer,
• Mouchumi Bhuyan and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26

• the presence of sacrificial electron donor substrates, such as aliphatic amines, flavins can photoreduce nitro arenes to anilines under blue light irradiation (Scheme 4). 4-Nitrophenyl phosphate was used as a substrate for photoreduction in water and in acetonitrile. The results summarized in Table 2

Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry

• Jiří Kulhánek,
• Filip Bureš and
• Miroslav Ludwig

Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11

• ], organic light-emitting diodes (OLED) [9] or functional polymers [10][11][12][13]. A typical push-pull chromophore consists of a polar A-π-D system with a planar π-system end-capped by a strong electron donor (D) and a strong electron acceptor (A). The π-conjugated system ensuring charge-transfer (CT

New diarylmethanofullerene derivatives and their properties for organic thin- film solar cells

• Daisuke Sukeguchi,
• Surya Prakash Singh,
• Mamidi Ramesh Reddy,
• Hideyuki Yoshiyama,
• Rakesh A. Afre,
• Yasuhiko Hayashi,
• Hiroki Inukai,
• Tetsuo Soga,
• Shuichi Nakamura,
• Norio Shibata and
• Takeshi Toru

Beilstein J. Org. Chem. 2009, 5, No. 7, doi:10.3762/bjoc.5.7

• -hexylthiophene) (P3HT) as the electron-donor and diarylmethanofullerene derivatives as the electron-acceptor material were examined. The {(methoxycarbonyl)phenyl[bis(octyloxy)phenyl]methano}fullerene showed power conversion efficiency as high as PCBM, but had higher solubility in a variety of organic solvents

• [19]. These first reduction potential data showed that the diarylmethanofullerene derivatives can be a better electron acceptor than PCBM [27]. Photovoltaic Devices A series of solar cells was fabricated with P3HT as the electron-donor and diarylmethanofullerene derivatives as the electron-acceptor