Imperial College London

Dr Florian Glöcklhofer

Faculty of Natural SciencesDepartment of Chemistry

Research Associate (Marie Skłodowska-Curie Fellow)
 
 
 
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Contact

 

f.glocklhofer Website

 
 
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Location

 

Molecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Publication Type
Year
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30 results found

Rosspeintner A, Glöcklhofer F, Pasitsuparoad P, Eder S, Fröhlich J, Angulo G, Vauthey E, Plasser Fet al., 2019, Effect of symmetric and asymmetric substitution on the optoelectronic properties of 9,10-dicyanoanthracene†, Molecular Systems Design and Engineering, Vol: 4, Pages: 951-961, ISSN: 2058-9689

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. </p> </div> </div> </div>

Journal article

Reichsöllner E, Creamer A, Cong S, Casey A, Eder S, Heeney M, Glocklhofer Fet 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.

Journal article

Rimmele M, Ableidinger K, Marsh AV, Cheetham NJ, Taublaender MJ, Buchner A, Prinz J, Fröhlich J, Unterlass MM, Heeney M, Glöcklhofer Fet 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.

Journal article

Reichsöllner E, Creamer A, Cong S, Casey A, Eder S, Heeney M, Glöcklhofer Fet 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.

Working paper

Glöcklhofer F, Rosspeintner A, Pasitsuparoad P, Eder S, Fröhlich J, Angulo G, Vauthey E, Plasser Fet al., Effect of symmetric and asymmetric substitution on the optoelectronic properties of 9,10-dicyanoanthracene, Molecular Systems Design & Engineering, Vol: 4, Pages: 951-961

<p>Six newly synthesised 9,10-dicyanoanthracene derivatives exhibit high two-photon absorption cross sections particularly upon symmetric substitution with strong electron donors.</p>

Journal article

Rimmele M, Ableidinger K, Marsh A, Cheetham N, Taublaender J, Buchner A, Prinz J, Fröhlich J, Unterlass M, Heeney M, Glöcklhofer Fet 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.

Working paper

Taublaender MJ, Glöcklhofer F, Marchetti-Deschmann M, Unterlass MMet 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

Journal article

Taublaender MJ, Glöcklhofer F, Marchetti-Deschmann M, Unterlass MMet 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

Journal article

Taublaender MJ, Glöcklhofer F, Marchetti-Deschmann M, Unterlass MMet 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

Journal article

Taublaender MJ, Glöcklhofer F, Marchetti-Deschmann M, Unterlass MMet al., 2018, Grüne und rasche hydrothermale Kristallisation und Synthese vollständig konjugierter aromatischer Verbindungen, Angewandte Chemie, Vol: 130, Pages: 12450-12454, ISSN: 0044-8249

Journal article

Gloecklhofer F, Stoeger B, Froehlich J, 2018, Synthesis of 1,2,5,6-and 1,4,5,8-anthracenetetrone: Building blocks for -conjugated small molecules and polymers, SYNTHETIC COMMUNICATIONS, Vol: 48, Pages: 2358-2365, ISSN: 0039-7911

Journal article

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.

Journal article

Kautny P, Glöcklhofer F, Kader T, Mewes J-M, Stöger B, Fröhlich J, Lumpi D, Plasser Fet 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>

Journal article

Gloecklhofer F, Morawietz AJ, Stoeger B, Unterlass MM, Froehlich Jet 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

Journal article

Gloecklhofer F, Kautny P, Fritz P, Stoeger B, Froehlich Jet al., 2017, Using Dicyanoanthracene Triflates as Superior Precursors: Modifying Properties by Sterically Hindered Aryl Substituents, CHEMPHOTOCHEM, Vol: 1, Pages: 51-55, ISSN: 2367-0932

Journal article

Lumpi D, Steindl J, Steiner S, Carl V, Kautny P, Schoen M, Gloecklhofer F, Holzer B, Stoeger B, Horkel E, Hametner C, Reider G, Mihovilovic MD, Froehlich Jet al., 2017, Thiophene ring-fragmentation reactions: Principles and scale-up towards NLO materials, TETRAHEDRON, Vol: 73, Pages: 472-480, ISSN: 0040-4020

Journal article

Glöcklhofer F, Kautny P, Fritz P, Stöger B, Fröhlich Jet 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

Journal article

Glöcklhofer F, Petritz A, Karner E, Bojdys MJ, Stadlober B, Fröhlich J, Unterlass MMet 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>

Journal article

Glöcklhofer F, Lunzer M, Stöger B, Fröhlich Jet 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

Journal article

Glöcklhofer F, Lunzer M, Stöger B, Fröhlich Jet 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

Journal article

Glöcklhofer F, Lunzer M, Stöger B, Fröhlich Jet 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

Journal article

Sohr B, Glöcklhofer F, Stöger B, Weil M, Fröhlich Jet al., 2016, cis,trans,cis-1,2,3,4-Tetrakis[2-(ethylsulfanyl)phenyl]cyclobutane, IUCrData, Vol: 1

<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>

Journal article

Gloecklhofer F, Lunzer M, Froehlich J, 2015, Facile Synthesis of Cyanoarenes from Quinones by Reductive Aromatization of Cyanohydrin Intermediates, SYNLETT, Vol: 26, Pages: 950-952, ISSN: 0936-5214

Journal article

Gloecklhofer F, Lumpi D, Kohlstaedt M, Yurchenko O, Wuerfel U, Froehlich Jet al., 2015, Towards continuous junction (CJ) organic electronic devices: Fast and clean post-polymerization modification by oxidation using dimethyldioxirane (DMDO), REACTIVE & FUNCTIONAL POLYMERS, Vol: 86, Pages: 16-26, ISSN: 1381-5148

Journal article

Glöcklhofer F, Fröhlich J, Stöger B, Weil Met al., 2014, Crystal structure oftrans-1,4-bis[(trimethylsilyl)oxy]cyclohexa-2,5-diene-1,4-dicarbonitrile, Acta Crystallographica Section E Structure Reports Online, Vol: 70, Pages: 77-79

<jats:p>The asymmetric unit of the title compound, C<jats:sub>14</jats:sub>H<jats:sub>22</jats:sub>N<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>Si<jats:sub>2</jats:sub>, contains one half of the molecule, which is completed by inversion symmetry. The cyclohexa-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 tetrahedral angle between the<jats:italic>sp</jats:italic><jats:sup>3</jats:sup>-C atom and the two neighbouring<jats:italic>sp</jats:italic><jats:sup>2</jats:sup>-C atoms in the cyclohexa-2,5-diene ring is enlarged by about 3°.</jats:p>

Journal article

Glöcklhofer F, Fröhlich J, Stöger B, Weil Met al., 2014, Crystal structures of 2,5-diazido-1,4-phenylene diacetate and 2,5-diazido-1,4-phenylene dibutyrate, Acta Crystallographica Section E Structure Reports Online, Vol: 70, Pages: 39-42

<jats:p>The asymmetric units of the title compounds, C<jats:sub>10</jats:sub>H<jats:sub>8</jats:sub>N<jats:sub>6</jats:sub>O<jats:sub>4</jats:sub>, (I), and C<jats:sub>14</jats:sub>H<jats:sub>16</jats:sub>N<jats:sub>6</jats:sub>O<jats:sub>4</jats:sub>, (II), each contain half of the respective molecule which is completed by inversion symmetry. The two molecules differ in the ester moiety (acetate<jats:italic>versus</jats:italic>butyrate) and the crystal symmetry is different,<jats:italic>i.e.</jats:italic>triclinic for (I) and monoclinic for (II). The diazidophenylene moieties are essentially planar [maximum deviation of 0.0216 (7) Å for (I) and 0.0330 (14) Å for (II)], and the ester functionalities are almost perpendicular to these planes, making dihedral angles of 79.93 (3)° for (I) and 79.42 (6)° for (II). In the crystals of both (I) and (II), there are no significant intermolecular interactions present.</jats:p>

Journal article

Gloecklhofer F, Lumpi D, Stoeger B, Froehlich Jet al., 2014, Multigram synthesis of bis[(trimethylsilyl)ethynyl]benzenes suitable for post-polymerization modification, NEW JOURNAL OF CHEMISTRY, Vol: 38, Pages: 2229-2232, ISSN: 1144-0546

Journal article

Lumpi D, Gloecklhofer F, Holzer B, Stoeger B, Hametner C, Reider GA, Froehlich Jet al., 2014, Systematic Investigations on 1,2,3-Triazole-Based Compounds Capable of Second Harmonic Generation, CRYSTAL GROWTH & DESIGN, Vol: 14, Pages: 1018-1031, ISSN: 1528-7483

Journal article

Mikula H, Svatunek D, Lumpi D, Gloecklhofer F, Hametner C, Froehlich Jet al., 2013, Practical and Efficient Large-Scale Preparation of Dimethyldioxirane, ORGANIC PROCESS RESEARCH & DEVELOPMENT, Vol: 17, Pages: 313-316, ISSN: 1083-6160

Journal article

Lumpi D, Glöcklhofer F, Stöger B, Reider GA, Hametner C, Horkel E, Fröhlich Jet al., 2012, Novel 1,2,3-triazole based compounds as quadratic nonlinear optical crystals

Systematic investigations towards a novel class of quadratic NLO materials, based on the application of 1,2,3-triazole moieties, are outlined to afford organic crystals displaying SHG nonlinearities of more than 9 times the value of KDP. © 2012 OSA.

Conference paper

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