- Branched oligothiophene silanes with the efficient nonradiative energy transfer between the fragments
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The synthesis of new dendrimers and branched oligothiophene silanes containing bithiophene groups at the periphery and quaterthiophene fragments at the center of the molecule is described. Specific features of bithiophene silane bromination were shown, and the conditions for the efficient synthesis of methyltris(5-bromo-2,2′-bithiophen-5-yl)silane have been found for the first time. The optical properties of the synthesized compounds were studied. The efficiency of the electron excitation energy transfer between the fragments of branched bi-and quaterthiophene silanes was measured.
- Borshchev,Ponomarenko,Kleymyuk,Luponosov,Surin,Muzafarov
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- Synthesis and characterisation of 1,2-difluoro-1,2-bis(5-trimethyl-silyl-2-thienyl)ethenes. A new family of conjugated monomers for oxidative polymerisation
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The synthesis of a series of (E)-1,2-difluoro-1,2-bis(2-thienyl)ethenes (DFDTEs) by low temperature reaction of 2-lithiothiophenes with tetrafluoroethene (TFE) is described. A possible explanation of the mechanism leading to the formation of higher oligomers is also elucidated together with the use of TMS as protecting group to prevent it. All compounds are thoroughly characterised and their E - configuration proved by vibrational spectroscopy. The crystal structure at 120 K of a representative system evidences its essential planarity and suggests significant delocalisation of π-electrons. Fluorine atoms are involved both in short intra- and intermolecular interactions with sulfur atoms and hydrogen atoms, apparently stabilising the planar molecular arrangement.
- Albertin, Luca,Bertarelli, Chiara,Gallazzi, Maria C.,Meille, Stefano V.,Capelli, Silvia C.
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- Reducing Energy Disorder of Hole Transport Layer by Charge Transfer Complex for High Performance p–i–n Perovskite Solar Cells
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Solution-processed organic semiconductor charge-transport layers (OS-CTLs) with high mobility, low trap density, and energy level alignment have dominated the important progress in p–i–n planar perovskite solar cells (pero-SCs). Unfortunately, their inevi
- Xu, Guiying,Xue, Rongming,Stuard, Samuel J.,Ade, Harald,Zhang, Chenjie,Yao, Jianlin,Li, Yaowen,Li, Yongfang
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- Continuous flow synthesis of organic electronic materials-case studies in methodology translation and scale-up
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The continuous flow synthesis of functional thiophene derivatives was examined. Methodology for the lithiation of thiophene building blocks was developed using a commercial bench-top flow reactor. In addition, the advantages of flow processing were demonstrated in the synthesis of a high performance organic dye in gram scale.
- Seyler, Helga,Haid, Stefan,Kwon, Tae-Hyuk,Jones, David J.,Baeuerle, Peter,Holmes, Andrew B.,Wong, Wallace W. H.
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- Heptafluoropropylation of Various Substituted Thiophenes with Bis(heptafluorobutyryl) Peroxide. Preparation of 3-Heptafluoropropylthiophen
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The heptafluoropropylations of several substituted thiophenes with bis(heptafluorobutyryl) peroxide were studied.The orientations of the heptafluoropropylation were examined and compared with those of usual electrophilic substitution.The method for the preparation of 3-heptafluoropropylthiophene was also explored.
- Yoshida, Masato,Yoshida, Tatsuro,Kamigata, Nobumasa,Kobayashi, Michio
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- Tuning the aggregation behaviour of BN-coronene diimides with imide substituents and their performance in devices (OLEDs and OFETs)
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Compared to perylene diimides (PDIs), coronene diimides (CDIs), which can be viewed as a lateral core extension, show undesired effects for optoelectronic devices such as the decrease of the absorption and a hypsochromic shift. Here, we demonstrate that, if the core is extended with two BN units as opposed to two CC units, the opposite is true: large bathochromic shifts can be achieved, together with higher molar extinction coefficients and beneficial luminescence properties,e.g.small Stokes shifts and high quantum yields (Φlum> 94%). These effects can be explained by the influence of the BN-unit on the frontier molecular orbitals of theBNCDIs. Different substitution motifs at the imide position, cyclohexyl and 2,6-diisopropylphenyl, although they had no influence on the optical properties on a single molecule level, influenced the aggregation substantially so that the optical properties in the solid state and the performance in organic devices (OLEDs and OFETs) differed considerably. In combination with host matrices, devices with EQEs of up to 1.5% and white light emission (0.317; 0.346) were obtained. The developed synthetic route starting from a regioisomeric pure 1,7-substituted PDI leads toBNCDIs in good yields, which makes this class of compounds very promising.
- Geffroy, Bernard,Hissler, Muriel,Hoffmann, Jonas,Jaques, Emmanuel,Staubitz, Anne
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supporting information
p. 14720 - 14729
(2021/11/09)
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- BN-Substituted coronene diimide donor-acceptor-donor triads: photophysical, (spectro)-electrochemical studies and Lewis behavior
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Boron/nitrogen substituted polyaromatic hydrocarbons (PAHs) are unique materials, with similar molecular structures to their carbon/carbon analogs, but different electronic properties. We report how these may be tuned by substitution at the B and/or N ato
- Hoffmann, Jonas,Jacquemin, Denis,Hissler, Muriel,Staubitz, Anne
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supporting information
p. 13926 - 13934
(2021/10/20)
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- Catalytic B-C Coupling by Si/B Exchange: A Versatile Route to π-Conjugated Organoborane Molecules, Oligomers, and Polymers
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Conjugated organoboranes have emerged as attractive hybrid materials for optoelectronic applications. Herein, a highly efficient, environmentally benign catalytic B-C bond formation method is presented that uses organosilicon compounds, dibromoboranes, and the metal-free organocatalyst Me3SiNTf2. This Si/B exchange approach has been successfully applied to the synthesis of arylborane molecules 4a-c, oligomers 8a,b, and polymers 8a′,b′. Photophysical investigations, supported by TD-DFT calculations, reveal highly effective π-conjugation in thienyl- and furylborane species; the latter are also highly emissive.
- Lik, Artur,Fritze, Lars,Müller, Lars,Helten, Holger
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supporting information
p. 5692 - 5695
(2017/05/04)
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- Synthesis and characterization of symmetrical sulfur-fused polycyclic aromatic hydrocarbons with controlled shapes
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Here we report and establish a facile synthetic method for these unprecedented sulfur-fused polycyclic aromatic hydrocarbons (S-PAHs) with symmetrical structures (C2-rectangle and D6h-hexagonal shape). Characterization by laser desor
- Yin, Jianghui,Hu, Yumiao,Zhang, Dengqing,Li, Xianying,Jin, Wusong
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p. 5794 - 5799
(2017/09/05)
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- Nucleophilic attack of R-lithium at tetrahedral silicon in alkoxysilanes. An alternate mechanism
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The currently accepted mechanism for nucleophilic attack at silicon in tetraalkoxysilanes, e.g. Si(OEt)4 is suggested to involve formation of penta- and then hexacoordinated intermediates as supported by the apparent exclusive formation of R3SiOR′ and R4Si from nucleophilic attack by RLi and RMgX. Our recent discovery of a direct route from biogenic silica to tetraalkoxyspirosiloxanes prompted us to revisit this reaction as a potential route to diverse silicon-containing species with single SiC bonds as early studies demonstrate that spirosiloxanes form quite stable pentacoordinated alkoxysilane compounds. As anticipated, Si(2-methyl-2,4-pentanediolato)2 (SP) reacts with RLi (R = Ph, anthracene, phenylacetylene, etc.) at -78 °C to form pentacoordinated Si, e.g. LiPhSP equilibrates with the starting reagents even at 3:1 ratios of PhLi:SP with no evidence for formation of hexacoordinated species by mass spectral, NMR and quenching studies. Thus, quenching with MeI or Me3SiCl allows isolation of monosubstituted products from RLi:SP; RSi(OR′)3 including some ring-opened oligomers. Comparative studies of reactions of PhLi with Si(OEt)4 allows isolation of mono- and disubstituted products again even at 1:1 ratios of PhLi:Si(OEt)4. However, on standing at -78 °C for long periods of time or on warming to 0 °C, the primary product for both reactions is Ph4Si even with 0.5 equivalents of PhLi. At reaction temperatures ≥0 °C the primary product is again Ph4Si. These results suggest that hexacoordinated intermediates are not part of the substitution mechanism and may suggest that the higher-substituted compounds arise from disproportionation processes. We also briefly describe the conversion of anthracenylSP and 9,9-dimethylfluoreneSP to silsesquioxanes.
- Furgal, Joseph C.,Laine, Richard M.
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p. 705 - 725
(2016/07/14)
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- SILYLATION OF AROMATIC HETEROCYCLES BY DISILANES USING POTASSIUM ALKOXIDE CATALYSTS
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The present invention describes chemical systems and methods for silylating heteroaromatic organic substrates, said system consisting essentially of a mixture of (a) at least one organodisilane and (b) at least alkoxide base, preferably a potassium alkoxide base, and said methods comprising contacting a quantity of the organic substrate with a mixture consisting essentially of (a) at least one organodisilane and (b) at least one alkoxide base, preferably a potassium alkoxide, under conditions sufficient to silylate the heteroaromatic substrate.
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Paragraph 0130
(2016/07/05)
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- Solution structure and chelation properties of 2-thienyllithium reagents
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The solution and chelation properties of 2-thienyllithium reagents with potential amine and ether chelating groups in the 3-position and related model systems have been investigated using low temperature 6Li, 7Li, 13C, and 31P NMR spectroscopy, 15N-labeling, and the effect of solvent additives. In THF-ether mixtures at low temperature 3-(N,N-dimethylaminomethyl)-2-thienyllithium (4) is ca. 99% dimer (which is chelated) and 1% monomer (unchelated), whereas 3-(methoxymethyl)-2-thienyllithium (5) is 10% dimer. Compound 5 crystallizes as a THF-solvated dimer, but there is no indication that the ether side chain is chelated in solution. Both 4 and 5 form PMDTA-complexed monomers almost stoichiometrically, similar to the model compound 2, in sharp contrast to phenyl analogues, which show very different behavior. The barriers to dimer interconversion are ca. 2 kcal/mol lower and chelation is significantly weaker in the 2-thienyllithium reagents than in their phenyl analogues.
- Jantzi, Kevin L.,Puckett, Craig L.,Guzei, Ilia A.,Reich, Hans J.
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p. 7520 - 7529
(2007/10/03)
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- Novel synthesis of arylboronic acids by electroreduction of aromatic halides in the presence of trialkyl borates
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A novel preparation of aryl and heteroarylboronic acids by an electrochemical coupling reaction is described. It is based on the reductive coupling between aromatic or heteroaromatic halides and a trialkyl borate. The reactions are carried out in DMF or THF with the use of sacrificial aluminium or magnesium anodes in a single-compartment cell. Arylboronic acids are obtained with moderate to good selectivities and isolated yields.
- Laza, Carine,Dunach, Elisabet,Serein-Spirau, Francoise,Moreau, Joel J. E.,Vellutini, Luc
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p. 373 - 375
(2007/10/03)
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- Studies in sulfur heterocycles. Part 13. An expedient synthesis of 7-hydroxybenzo[b]thiophene and its 2- and 3-substituted derivatives
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Two expedient routes to 7-hydroxybenzo[b]thiophene and its 2- and 3-substituted derivatives from readily available starting materials are described which constitute a vast improvement over the known methods of synthesis.
- Samanta, Subhendu Sekhar,Ghosh, Sukhen Chandra,De, Asish
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p. 2683 - 2685
(2007/10/03)
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- Structure of Thiophene-Based Regioregular Polymers and Block Copolymers and Its Influence on Luminescence Spectra
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Two approaches toward control of the luminescence wavelength of polythiophenes have been explored: (i) block copolymers in which oligothiophene blocks alternate with oligosilanylene blocks and (ii) regioregular polythiophenes in which oligothiophene sequences are delimited by n-octyl substituents placed in a "head-to-head" fashion on adjacent rings.Both methods aim at restricting the ?-conjugation to the oligothiophene sequences.The block copolymer approach is very effective, whereas the (solution) luminescence spectra of the regioregular polymers are strongly red-shifted with respect to absorption and confined to a narrow range of wavelengths.This is due to the quinoid character of the excited singlet state, in which there is a strong electronic driving force toward coplanarity of adjacent thiophene rings, which offsets the steric hindrance of the octyl substituents and increases the size of the conjugating ?-system.This explanation is supported by calculations and by spectral data of substituted bithiophenes.
- Hutten, Paul F. van,Gill, Richard E.,Herrema, Jan K.,Hadziioannou, Georges
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p. 3218 - 3224
(2007/10/02)
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- NOVEL HALOGENATION OF THIOPHENES WITH BENZENESELENINYL CHLORIDE AND ALUMINUM HALIDE
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In the presence of aluminum halide, benzeneseleninyl chloride is an efficient regioselective halogenating reagent for heterocyclic compounds such as thiophene, 2-methylthiophene, 3-methylthiophene, 2,5-dimethylthiophene, and furan.In the case of pyrrole, no halogenated product was obtained.A plausible reaction mechanism involving a positive halogen intermediate is proposed.
- Kamigata, Nobumasa,Suzuki, Takashi,Yoshida, Masato
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- Synthesis of Trimethylsilyloxy and Hydroxy Compounds from Carbanions and Bis(trimethylsilyl)peroxide.
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The reactions of bis(trimethylsilyl)peroxide with alkyl, vinyl, alkynyl, aromatic and heteroaromatic anions are described.Depending on the reaction conditions, the trimethylsilyloxy derivatives can be obtained alone or together with the corresponding trimethylsilyl derivatives, which is sometimes the major product.Enolates, generated using magnesium diisopropylamide give the corresponding hydroxycarbonyl compounds in good yields.An attempt to rationalise the above results is given, emphasising the wide use of bis(trimethylsilyl)peroxide in organic synthesis as an electrophilic hydroxylation reagent.
- Camici, Lucia,Dembech, Pasquale,Ricci, Alfredo,Seconi, Giancarlo,Taddei, Maurizio
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p. 4197 - 4206
(2007/10/02)
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- Activation of C-H Bonds of Heterocyclic and Alicyclic Compounds Using Calcium Atom
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Calcium atoms have been inserted into C-H bonds of heterocyclic (furans and thiophene) and alicyclic compounds (cyclohexanes and cyclopentane) to give the corresponding organocalcium hydrides.The organocalcium hydrides thus produced reacted with trimethylchlorosilane to give trimethylsilyl-substituted heterocyclic and alicyclic compounds, and a reduced product (trimethylsilane).
- Mochida, Kunio,Kojima, Kenji,Yoshida, Yasuhiro
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p. 2255 - 2256
(2007/10/02)
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- Electrophilic Hydroxylation with Bis(trimethylsilyl)peroxide. A Synthon for the Hydroxyl Cation
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The regiospecific introduction of an hydroxy group in aromatic and aliphatic compounds can be performed in good yields by electrophilic hydroxylation of their organometallic derivatives with bis(trimethylsilyl)peroxide.
- Taddei, Maurizio,Ricci, Alfredo
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p. 633 - 635
(2007/10/02)
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- PYROLYSIS OF SILICON-CONTAINING CYCLIC POLYSULPHIDES
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Thermal decomposition of silicon-containing monocyclic polysulphides (1-methyl-3-trimethylsilyl-2,5-dithiacyclopentane (I), 1,4-bis(trimethylsilyl)-2,3,6,7-tetrathiacyclooctane (II) and 1-trimethylsilyl-2,3,4,5,6-pentathiacycloheptane (III)) has been stud
- Chernyshev, E. A.,Kuz'min, O. V.,Lebedev, A. V.,Zaikin, V. G.,Mikaya, A. I.
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p. 231 - 238
(2007/10/02)
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- THE RATES OF BASE CLEAVAGE OF SUBSTITUTED 2-THIENYLTRIMETHYLSILANES. AB INITIO CALCULATIONS OF THE ACIDITIES OF MONOSUBSTITUTED THIOPHENS
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Rates of cleavage in NaOMe-MeOH at 50 deg C have been determined for the mono-substituted 2-trimethylsilylthiophens X*C4H2S*SiMe3-2 with X = H, 3-NO2, 3-Br, 4-Br-, and 5-NO2, -CN, -COPh, -Me, -OMe and -NMe2, and for one disubstituted compound, 4,5-Br2*C4HS*SiMe3-2.For several compounds the rate and product isotope effects have also been determined.The energies involved in the process X*C4H3S X*C4H2S- for deprotonation at the 2-position have been calculated by an ab initio method (STO-3G), and the results used in analysis of the substituent effects in the cleavage of the XC4H2S*SiMe3-2 compounds.The results are consistent with the view the aryl anions separate in the rate-determining step of the cleavage.The isotope effects are all close to unity, whereas by comparison with results for XC6H4CH2SiMe3 and related species of similar reactivity, values in the region of 10 would be expected for the 3- and 5-NO2 compounds if the product isotope effect for a carbanion R depended only in the pKa of RH.The difference between the thienyl- and benzyl-type anions is attributed to the absence of conjugative delocalization of the charge in the former. Approximate pKa values are derived for the 2-positions of the X*C4H3S compounds.
- Seconi, Giancarlo,Eaborn, Colin,Stamper, John G.
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p. 153 - 168
(2007/10/02)
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