Publications
65 results found
Eder S, Yoo D-J, Nogala W, et al., 2020, Switching between local and global aromaticity in a conjugated macrocycle for high-performance organic sodium-ion battery anodes, Angewandte Chemie International Edition, Vol: 59, Pages: 12958-12964, ISSN: 1433-7851
Aromatic organic compounds can be used as electrode materials in rechargeable batteries and are expected to advance the development of both anode and cathode materials for sodium-ion batteries (SIBs). However, most aromatic organic compounds assessed as anode materials in SIBs to date exhibit significant degradation issues under fast-charge/discharge conditions and unsatisfying long-term cycling performance. Now, a molecular design concept is presented for improving the stability of organic compounds for battery electrodes. The molecular design of the investigated compound, [2.2.2.2]paracyclophane-1,9,17,25-tetraene (PCT), can stabilize the neutral state by local aromaticity and the doubly reduced state by global aromaticity, resulting in an anode material with extraordinarily stable cycling performance and outstanding performance under fast-charge/discharge conditions, demonstrating an exciting new path for the development of electrode materials for SIBs and other types of batteries.
Meindl B, Pfennigbauer K, Stöger B, et al., 2020, Double ring-closing approach for the synthesis of 2,3,6,7-substituted anthracene derivatives., Journal of Organic Chemistry, Vol: 85, Pages: 8240-8244, ISSN: 0022-3263
A method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain, is presented. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable, protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions, followed by a deprotection and intramolecular double ring-closing condensation reaction.
Hodsden T, Thorley KJ, Panidi J, et al., 2020, Core fluorination enhances solubility and ambient stability of an IDT‐based n‐type semiconductor in transistor devices, Advanced Functional Materials, Vol: 30, Pages: 1-12, ISSN: 1616-301X
The synthesis of a novel fluorinated n‐type small molecule based on an indacenodithiophene core is reported. Fluorination is found to have a significant impact on the physical properties, including a surprisingly dramatic improvement in solubility, in addition to effectively stabilizing the lowest‐unoccupied molecular orbital energy (−4.24 eV). Single‐crystal analysis and density functional theory calculations indicate the improved solubility can be attributed to backbone torsion resulting from the positioning of the fluorine group in close proximity to the strongly electron‐withdrawing dicyanomethylene group. Organic thin‐film transistors made via blade coating display high electron mobility (up to 0.49 cm2 V−1 s−1) along with good retention of performance in ambient conditions.
Meindl B, Pfennigbauer K, Stöger B, et al., 2020, Double ring-closing approach for the synthesis of 2,3,6,7-substituted anthracene derivatives, Publisher: ChemRxiv
<jats:p>Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br></jats:p>
Glöcklhofer F, Rosspeintner A, Pasitsuparoad P, et al., 2019, Effect of symmetric and asymmetric substitution on the optoelectronic properties of 9,10-dicyanoanthracene, Molecular Systems Design & Engineering, Vol: 4, Pages: 951-961, ISSN: 2058-9689
<p>Six newly synthesised 9,10-dicyanoanthracene derivatives exhibit high two-photon absorption cross sections particularly upon symmetric substitution with strong electron donors.</p>
Rosspeintner A, Glöcklhofer F, Pasitsuparoad P, et al., 2019, Effect of Symmetric and Asymmetric Substitution on the Optoelectronic Properties of 9,10-Dicyanoanthracene
<jats:p>A set of substituted 9,10-dicyanoanthracenes (DCA) has been synthesized, their photophysical and electrochemical properties in liquid solution have been characterized and supplemented by high level ab initio quantum chemical calculations. Three different methoxy-group-containing substituents have been linked to the DCA core in a symmetric and asymmetric fashion to produce six different species with strong quadrupole and dipole moments, respectively. The major difference between the symmetrically and asymmetrically substituted species are the enhanced two-photon absorption intensities of the former. In most of the cases studied, the molecules show reasonably large optical transition probabilities. The fluorescence brightness of these substances makes them interesting objects for two-photon absorption applications. Additionally, all molecules can be both easily reduced and oxidized electrochemically and are therefore suitable for optoelectronic applications.</jats:p>
Reichsöllner E, Creamer A, Cong S, et al., 2019, Fast and selective post-polymerization modification of conjugated polymers using dimethyldioxirane, Frontiers in Chemistry, Vol: 7, ISSN: 2296-2646
Modification of functional groups attached to conjugated polymer backbones can drastically alter the material properties. Oxidation of electron-donating thioalkyl substituents to electron-withdrawing sulfoxides or sulfones is a particularly effective modification. However, so far, this reaction has not been studied for the modification of conjugated polymers used in organic electronics. Crucial questions regarding selectivity and reaction time waited to be addressed. Here, we show that the reaction is highly selective and complete within just a few minutes when using dimethyldioxirane (DMDO) for the oxidation of thioalkyl substituents attached to the well-investigated conjugated polymers poly(9-(1-octylnonyl)carbazole-alt-4,7-dithienylbenzothiadiazole) (PCDTBT) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT). The selectivity was confirmed by comparison with polymers obtained from pre-oxidized monomers and by control experiments using related polymers without thioalkyl substituents. Using DMDO, the oxidation yields acetone as the only side-product, which reduces the work-up to mere evaporation of solvents and excessive reagent. Our results show that this oxidation is an exciting method for the preparation of electron-deficient conjugated polymers. It may even allow the preparation of electron acceptors for solar cells directly from the electron donors.
Rimmele M, Ableidinger K, Marsh AV, et al., 2019, Thioalkyl- and Sulfone-Substituted Poly(p-Phenylene Vinylene)s, Polymer Chemistry, Vol: 10, Pages: 738-750, ISSN: 1759-9954
Poly(p-phenylene vinylene)s (PPVs) have been studied for decades, but research on this interesting class of conjugated polymers is far from being completed. New applications like in bioimaging keep emerging and even simple structural variations are still waiting to be explored. Surprisingly, not even dithioalkyl-substituted PPVs (S-PPVs) have been reported in the peer-reviewed literature, although the corresponding dialkoxy-substituted PPVs (O-PPVs) like MEH-PPV or MDMO-PPV are most frequently used and although thioalkyl substituents can improve the material properties significantly. We herein report the development of a highly efficient, scalable two-step synthesis of Gilch monomers for S-PPVs starting from low-cost 1,4-diiodobenzene. A low-temperature polymerization protocol has been developed for these monomers, affording high-molecular weight S-PPVs in excellent yields. The thermal, electrochemical, and photophysical properties of S-PPVs are reported to highlight the potential of these polymers. Furthermore, treatment with dimethyldioxirane is demonstrated to result in rapid conversion into sulfone-substituted PPVs (SO2-PPVs), introducing a route to high-molecular weight SO2-PPVs with exceptional stability and solid-state photoluminescence quantum yields of up to 0.46.
Reichsöllner E, Creamer A, Cong S, et al., 2019, Fast and Selective Post-Polymerization Modification of Conjugated Polymers Using Dimethyldioxirane
<jats:p>Modification of functional groups attached to conjugated polymer backbones can drastically alter the material properties. Oxidation of electron-donating thioalkyl substituents to electron-withdrawing sulfoxides or sulfones is a particularly effective modification. However, so far, this reaction has not been studied for the modification of conjugated polymers used in organic electronics. Crucial questions regarding selectivity and reaction time waited to be addressed. Here, we show that the reaction is highly selective and complete within just a few minutes when using dimethyldioxirane (DMDO) for the oxidation of thioalkyl substituents attached to the well investigated conjugated polymers poly(9-(1-octylnonyl)carbazole-alt-4,7-dithienylbenzothiadiazole) (PCDTBT) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT). The selectivity was confirmed by comparison with polymers obtained from pre-oxidized monomers and by control experiments using related polymers without thioalkyl substituents. Using DMDO, the oxidation yields acetone as the only side-product, which reduces the work-up to mere evaporation of solvents and excessive reagent. Our results show that this oxidation is an exciting method for the preparation of electron-deficient conjugated polymers. It may even allow the preparation of electron acceptors for solar cells directly from the electron donors.</jats:p>
Reichsöllner E, Creamer A, Cong S, et al., 2019, Fast and selective post-polymerization modification of conjugated polymers using dimethyldioxirane.
Modification of functional groups attached to conjugated polymer backbones can drastically alter the material properties. Oxidation of electron-donating thioalkyl substituents to electron-withdrawing sulfoxides or sulfones is a particularly effective modification. However, so far, this reaction has not been studied for the modification of conjugated polymers used in organic electronics. Crucial questions regarding selectivity and reaction time waited to be addressed. Here, we show that the reaction is highly selective and complete within just a few minutes when using dimethyldioxirane (DMDO) for the oxidation of thioalkyl substituents attached to the well investigated conjugated polymers poly(9-(1-octylnonyl)carbazole-alt-4,7-dithienylbenzothiadiazole) (PCDTBT) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT). The selectivity was confirmed by comparison with polymers obtained from pre-oxidized monomers and by control experiments using related polymers without thioalkyl substituents. Using DMDO, the oxidation yields acetone as the only side-product, which reduces the work-up to mere evaporation of solvents and excessive reagent. Our results show that this oxidation is an exciting method for the preparation of electron-deficient conjugated polymers. It may even allow the preparation of electron acceptors for solar cells directly from the electron donors.
Rimmele M, Ableidinger K, Marsh A, et al., 2018, Thioalkyl- and Sulfone-Substituted Poly(p-Phenylene Vinylene)s, Publisher: Royal society of chemistry
Poly(p-phenylene vinylene)s (PPVs) have been studied for decades, but research on this interesting class of conjugated polymers is far from being completed. New applications like in bioimaging keep emerging and even simple structural variations are still waiting to be explored. Surprisingly, not even dithioalkyl-substituted PPVs (S-PPVs) have been reported in the peer-reviewed literature, although the corresponding dialkoxy-substituted PPVs (O-PPVs) like MEH-PPV or MDMO-PPV are most frequently used and although thioalkyl substituents can improve the material properties significantly. We herein report the development of a highly efficient, scalable two-step synthesis of Gilch monomers for S-PPVs starting from low-cost 1,4-diiodobenzene. A low-temperature polymerization protocol has been developed for these monomers, affording high-molecular weight S-PPVs in excellent yields. The thermal, electrochemical, and photophysical properties of S-PPVs are reported to highlight the potential of these polymers. Furthermore, treatment with dimethyldioxirane is demonstrated to result in rapid conversion into sulfone-substituted PPVs (SO<sub>2</sub>-PPVs), introducing a route to high-molecular weight SO<sub>2</sub>-PPVs with exceptional stability and solid-state photoluminescence quantum yields of up to 0.46.
Taublaender MJ, Glöcklhofer F, Marchetti-Deschmann M, et al., 2018, Innentitelbild: Grüne und rasche hydrothermale Kristallisation und Synthese vollständig konjugierter aromatischer Verbindungen (Angew. Chem. 38/2018), Angewandte Chemie, Vol: 130, Pages: 12358-12358, ISSN: 0044-8249
Entgegen der chemischen Intuition genügen Wasser und hohe Temperaturen, um komplett konjugierte aromatische Verbindungen rasch zu synthetisieren und zu kristallisieren. In ihrer Zuschrift auf S. 12450 berichten M. M. Unterlass et al. über die Hydrothermal‐Kristallisation von Indigo, Pentacentetron und Perinon sowie über die direkte Synthese von Perinon aus Naphthalin‐Bisanhydrid und o‐Phenylendiamin bei hohen Temperaturen in Wasser ohne Kosolventien oder Katalysatoren. Das Bild zeigt stilisierte Kristalle und Moleküle des roten Pigments trans‐Perinon in wässriger Umgebung.
Taublaender MJ, Glöcklhofer F, Marchetti-Deschmann M, et al., 2018, Grüne und rasche hydrothermale Kristallisation und Synthese vollständig konjugierter aromatischer Verbindungen [Green and rapid hydrothermal crystallization and synthesis of fully conjugated aromatic compounds], Angewandte Chemie, Vol: 130, Pages: 12450-12454, ISSN: 0044-8249
Highly condensed, fully conjugated aromatic compounds are interesting candidates for application in organic electronics. Their electronic properties improve with increasing crystallinity. Here it is shown that the crystallization of three archetypes of such molecules - pentacentetron, indigo and perinone - can be achieved hydrothermally. This finding is extremely astonishing in view of the structure of these compounds. Furthermore, it is shown that perinone can be produced from naphthalene bisanhydride and o ‐ phenylenediamine in exclusively high-temperature water and without the addition of cosolvents or catalysts. Furthermore, the transformation can be accelerated drastically through the use of microwave radiation.
Taublaender MJ, Glöcklhofer F, MarchettiDeschmann M, et al., 2018, Green and Rapid Hydrothermal Crystallization and Synthesis of Fully Conjugated Aromatic Compounds, Angewandte Chemie International Edition, Vol: 57, Pages: 12270-12274, ISSN: 1433-7851
<jats:title>Abstract</jats:title><jats:p>Highly fused, fully conjugated aromatic compounds are interesting candidates for organic electronics. With higher crystallinity their electronic properties improve. It is shown here that the crystallization of three archetypes of such molecules—pentacenetetrone, indigo, and perinone—can be achieved hydrothermally. Given their molecular structure, this is a truly startling finding. In addition, it is demonstrated that perinone can also be synthesized in solely high‐temperature water from the starting compounds naphthalene bisanhydride and <jats:italic>o</jats:italic>‐phenylene diamine without the need for co‐solvents or catalysts. The transformation can be drastically accelerated by the application of microwave irradiation. This is the first report on the hydrothermal generation of two fused heterocycles.</jats:p>
Taublaender MJ, Glöcklhofer F, Marchetti-Deschmann M, et al., 2018, Inside Cover: Green and Rapid Hydrothermal Crystallization and Synthesis of Fully Conjugated Aromatic Compounds (Angew. Chem. Int. Ed. 38/2018), Angewandte Chemie International Edition, Vol: 57, Pages: 12180-12180, ISSN: 1433-7851
Glöcklhofer F, Stöger B, Fröhlich J, 2018, Synthesis of 1,2,5,6- and 1,4,5,8-anthracenetetrone: Building blocks for π-conjugated small molecules and polymers, Synthetic Communications, Vol: 48, Pages: 2358-2365, ISSN: 0039-7911
Reliable reactions for the synthesis of two interesting anthracenetetrones have been identified and optimized. Both syntheses start from dihydroxy-9,10-anthraquinones and were selected for maximized efficiency and minimized work load. Work-up of all reactions can be achieved without column chromatography, which facilitates further scale-up. So far, both target compounds are considerably underexplored despite their promising molecular structure for use in devices and in organic synthesis, especially as building blocks for π-conjugated compounds. The crystal structure of 1,4,5,8-anthracentetrone is reported.
Glöcklhofer F, Stöger B, Fröhlich J, 2018, Synthesis of 1,2,5,6- and 1,4,5,8-anthracenetetrone: building blocks for π-conjugated small molecules and polymers, Publisher: ChemRxiv
Reliablereactions for the synthesis of two interestinganthracenetetrones have been identified and optimized. Both synthesesstart from dihydroxy-9,10-anthraquinones and were selected formaximized efficiency and minimized work load. Work-up of allreactions can be achieved without column chromatography, whichfacilitates further scale-up. So far, both target compounds areconsiderably underexplored despite their promising molecularstructure for use in devices and in organicsynthesis, especially as building blocks for π-conjugated compounds.The crystal structure of 1,4,5,8-anthracentetrone is reported.
Kautny P, Glöcklhofer F, Kader T, et al., 2017, Charge-transfer states in triazole linked donor–acceptor materials: strong effects of chemical modification and solvation, Physical Chemistry Chemical Physics, Vol: 19, Pages: 18055-18067, ISSN: 1463-9076
<p>A new series of push–pull chromophores are synthesized, spectroscopically characterized, and their excited state energies and wavefunctions are elucidated by high-level computational methods.</p>
Gloecklhofer F, Morawietz AJ, Stoeger B, et al., 2017, Extending the scope of a new cyanation: design and synthesis of an anthracene derivative with an exceptionally low LUMO level and improved solubility, ACS Omega, Vol: 2, Pages: 1594-1600, ISSN: 2470-1343
The preparation of cyanated acenes from quinones has been improved for the conversion of electron-poor starting materials. The new procedure was used to prepare rationally designed 2,7-dinitro-9,10-dicyanoanthracene. Crystallographic, morphological, and electrochemical investigations have revealed most promising properties for applications in organic electronics.
Glöcklhofer F, Petritz A, Karner E, et al., 2017, Dicyano- and tetracyanopentacene: foundation of an intriguing new class of easy-to-synthesize organic semiconductors, Journal of Materials Chemistry C, Vol: 5, Pages: 2603-2610, ISSN: 2050-7526
<p>Extraordinarily low LUMO levels, dense molecular packing, an intriguing packing motif, reversible bleaching and OTFT operability under ambient conditions are revealed in a detailed investigation of multi-cyanated pentacenes.</p>
Glöcklhofer F, Kautny P, Fritz P, et al., 2017, Back cover: using dicyanoanthracene triflates as superior precursors: modifying properties by sterically hindered aryl substituents (ChemPhotoChem 2/2017), ChemPhotoChem, Vol: 1, Pages: 76-76, ISSN: 2367-0932
The Back Cover picture shows an exploding light bulb, both as a symbol for the knowledge explosion taking place in photochemistry and also representing the end of an old technology, soon to be replaced by large area lighting using new materials such as 9,10‐dicyanoanthracenes. More information on the synthesis and properties of these materials can be found in the Communication by F. Glöcklhofer et al. on page 51 in Issue 2, 2017 (DOI:10.1002/cptc.201600018).
Gloecklhofer F, Kautny P, Fritz P, et al., 2017, Using dicyanoanthracene triflates as superior precursors: modifying properties by sterically hindered aryl substituents, Chemphotochem, Vol: 1, Pages: 51-55, ISSN: 2367-0932
The preparation of 9,10‐dicyanoanthracene triflates is reported. Taking advantage of the high reactivity of these precursors in Suzuki coupling reactions, sterically hindered substituents were introduced. The impact of the substituents on the crystallographic and photophysical properties was investigated. The results highlight the usefulness of the new triflate derivatives and the substituents for the development of 9,10‐dicyanoanthracene‐based materials.
Lumpi D, Steindl J, Steiner S, et al., 2017, Thiophene ring-fragmentation reactions: Principles and scale-up towards NLO materials, TETRAHEDRON, Vol: 73, Pages: 472-480, ISSN: 0040-4020
Glöcklhofer F, Lunzer M, Stöger B, et al., 2016, Cover Picture: A Versatile One‐Pot Access to Cyanoarenes from ortho‐ and para‐Quinones: Paving the Way for Cyanated Functional Materials (Chem. Eur. J. 15/2016), Chemistry – A European Journal, Vol: 22, Pages: 5021-5021, ISSN: 0947-6539
Glöcklhofer F, Lunzer M, Stöger B, et al., 2016, A Versatile One‐Pot Access to Cyanoarenes from ortho‐ and para‐Quinones: Paving the Way for Cyanated Functional Materials, Chemistry – A European Journal, Vol: 22, Pages: 5025-5025, ISSN: 0947-6539
<jats:title>Abstract</jats:title><jats:p>Invited for the cover of this issue is the team of Florian Glöcklhofer at the TU Wien. The cover reflects the ups and downs they experienced during the investigation of the novel synthesis of cyanoarenes from quinones, which is highlighted by the magnifying glass. The sometimes exhausting experiments were finally rewarded by the versatile new one‐pot reaction presented in the accompanying full paper. The significance for the field of material chemistry is illustrated by the blueprint showing the crystal structure of 6,13‐dicyanopentacene. Read the full text of the article at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://dx.doi.org/10.1002/chem.201600004">10.1002/chem.201600004</jats:ext-link>.</jats:p>
Gloecklhofer F, Lunzer M, Stoeger B, et al., 2016, A Versatile One-Pot Access to Cyanoarenes from ortho- and para-Quinones: Paving the Way for Cyanated Functional Materials, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 22, Pages: 5173-5180, ISSN: 0947-6539
Sohr B, Glöcklhofer F, Stöger B, et al., 2016, cis,trans,cis-1,2,3,4-Tetrakis[2-(ethylsulfanyl)phenyl]cyclobutane, IUCrData, Vol: 1, ISSN: 2414-3146
<jats:p>The title cyclobutane derivative, C<jats:sub>36</jats:sub>H<jats:sub>40</jats:sub>S<jats:sub>4</jats:sub>, formed serendipitously through a photochemically initiated [2 + 2] cycloaddition. The asymmetric unit contains half a molecule with the 2-(ethylsulfanyl)phenyl substituents in a<jats:italic>cis</jats:italic>configuration, the other half of the molecule being generated by the application of a twofold rotation operation. The substituents in both halves of the molecules are in a<jats:italic>trans</jats:italic>arrangement relative to each other. The cyclobutane ring shows angular and torsional strains, with C—C—C bond angles of 89.80 (8) and 88.40 (8)°, and an average absolute torsion angle of 14.28 (10)°. The angle of pucker in the ring is 20.27 (12)°. The C<jats:sub>cb</jats:sub>—C<jats:sub>cb</jats:sub>—C<jats:sub>b</jats:sub>angles between the cyclobutane (cb) ring atoms and the attached benzene (b) ring atoms are widened and range from 115.19 (10) to 121.66 (10)°. A weak intramolecular C—H...S hydrogen-bonding interaction between one of the cyclobutane ring H atoms and the S atom may help to establish the molecular conformation. No specific intermolecular interactions are found.</jats:p>
Gloecklhofer F, Lunzer M, Froehlich J, 2015, Facile synthesis of cyanoarenes from quinones by reductive aromatization of cyanohydrin intermediates, Synlett: accounts and rapid communications in synthetic organic chemistry, Vol: 26, Pages: 950-952, ISSN: 0936-5214
A novel synthesis of cyanoarenes from quinones by using PCl3 as the reagent for reductive aromatization of cyanohydrin intermediates is reported. In situ IR spectroscopic measurements were conducted to monitor the reactions and to develop a convenient one-pot protocol. 1,4-Dicyanobenzene and 9,10-dicyanoanthracene were prepared by the new procedure.
Gloecklhofer F, Lumpi D, Kohlstaedt M, et al., 2015, Towards continuous junction (CJ) organic electronic devices: Fast and clean post-polymerization modification by oxidation using dimethyldioxirane (DMDO), Reactive and Functional Polymers, Vol: 86, Pages: 16-26, ISSN: 1381-5148
An advanced design concept for organic electronic devices relying on functional polymers is presented. The concept aims at realizing a gradual transition from an electron-donating to an electron-accepting material in a specific post-polymerization modification step. Hence, this approach facilitates a straight forward fabrication compared to conventional multi-layer architectures. The synthesis via microwave-assisted Cu(I)-catalyzed azide–alkyne cycloaddition of the reactive polymers based on sulfur, selenium and tellurium as active sites is presented; full characterization of model compounds and polymers is provided. Additionally, a reliable procedure for post-polymerization oxidation applying dimethyldioxirane is developed. Photophysical and electrochemical characteristics of the novel polymers reveal the feasibility but also the challenges of the continuous junction concept.
Glöcklhofer F, Fröhlich J, Stöger B, et al., 2014, Crystal structure of trans-1,4-bis-[(trimethylsilyl)oxy]cyclohexa-2,5-diene-1,4-dicarbonitrile, Acta Crystallogr Sect E Struct Rep Online, Vol: 70, Pages: 77-79, ISSN: 1600-5368
The asymmetric unit of the title compound, C14H22N2O2Si2, contains one half of the mol-ecule, which is completed by inversion symmetry. The cyclo-hexa-2,5-diene ring is exactly planar and reflects the bond-length distribution of a pair of located double bonds [1.3224 (14) Å] and two pairs of single bonds [1.5121 (13) and 1.5073 (14) Å]. The tetra-hedral angle between the sp (3)-C atom and the two neighbouring sp (2)-C atoms in the cyclo-hexa-2,5-diene ring is enlarged by about 3°.
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