PREPRINT UNDER REVIEW

Visualisation of Chemical Shielding Tensors (VIST) to Elucidate Aromaticity and Antiaromaticity [Preprint link, open access]

F. Plasser,* F. Glöcklhofer

ChemRxiv 2021, DOI:10.26434/chemrxiv.13580885

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Aromaticity is a central concept in chemistry, pervading areas from biochemistry to materials science. Recently, chemists also started to exploit intricate phenomena such as the interplay of local and global (anti)aromaticity or aromaticity in non-planar systems and three dimensions. These phenomena pose new challenges in terms of our fundamental understanding and the practical visualisation of aromaticity. To overcome these challenges, a method for the visualisation of chemical shielding tensors (VIST) is developed here that allows for a 3D visualisation with quantitative information about the local variations and anisotropy of the chemical shielding. After exemplifying the method in different planar hydrocarbons, we study two non-planar macrocycles to show the unique benefits of the VIST method for molecules with competing π-conjugated systems and conclude with a norcorrole dimer showing clear evidence of through-space aromaticity. We believe that the VIST method will be a highly valuable addition to the computational toolbox.

JOURNAL ARTICLES

12 corresponding author papers shown in frames

2021
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26. The influence of alkyl group regiochemistry and backbone fluorination on the packing and transistor performance of N-cyanoimine functionalised indacenodithiophenes [Link, open access]

T. Hodsden, K. J. Thorley, A. Basu, A. J. P. White, C. Wang, W. Mitchell, F. Glöcklhofer, T. D. Anthopoulos, M. Heeney*

Mater. Adv. 2021, DOI:10.1039/D1MA00091H

The synthesis of two novel n-type molecular organic semiconductors based on a fluorinated indacenodithiophene core in combination with an electron withdrawing N-cyanoimine group is reported, and the influence of the regiochemistry of the solubilizing sidechain is investigated. The N-cyanoimine is confirmed to be a strongly electron accepting group, which in combination with the core fluorination resulted in high electron affinities for both materials. Single crystal analysis demonstrated that whilst both materials arrange in ordered slipped stacks with close π-π stacking distances (~ 3.40 Å), significant differences in electron transfer integrals for the two regioisomers were observed, relating to differences in relative molecular displacement along the π-stacking direction. Organic thin-film transistors fabricated via blade-coating displayed electron mobility up to 0.13 cm2 V-1 s-1 for the isomer with the larger transfer integral.

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25. One‐step Six‐fold Cyanation of Benzothiadiazole Acceptor Units for Air‐Stable High‐Performance n‐Type Organic Field‐Effect Transistors [Link, open access]

P. Kafourou, B. Park, J. Luke, L. Tan, J. Panidi, F. Glöcklhofer, J. Kim, T. D. Anthopoulos, J.-S. Kim, K. Lee, S. Kwon,* M. Heeney*

Angew. Chem., Int. Ed. 2021, DOI:10.1002/anie.202013625

Angew. Chem. 2021, DOI:10.1002/ange.202013625

We report a new high electron affinity acceptor end group for organic semiconductors, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT). An n‐type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a six‐fold nucleophilic substitution with cyanides on a fluorinated precursor, itself prepared by a direct arylation approach. This one‐step chemical modification was found to significantly impact the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n‐type semiconductor. The highly electron‐deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n‐type organic field‐effect transistors (OFETs). Solution‐processed OFETs based on TCNBT IDT exhibited a charge carrier mobility of up to µe ≈ 0.15 cm2 V‐1 s‐1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach.

2020
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24. Multibranched aliphatic side chains for π-conjugated polymers with a high density of ‘unshielded’ aromatics [Link, open access]

S. Wang, J. Shaw, Y. Han, Z. Fei, F. Glöcklhofer,* M. Heeney*

Chem. Commun. 2020, 56, 12138-12141. DOI:10.1039/D0CC04967K

The synthesis of strongly solubilising multibranched aliphatic side chains for π-conjugated polymers is reported. The solubilising capability of the side chains and their effect on the polymer properties are studied on the example of copolymers composed of up to six unsubstituted, ‘unshielded’ thiophene units per side chain-substituted naphthalene diimide unit.

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23. Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives [Link] [Preprint link, open access]

B. Meindl,# K. Pfennigbauer,# B. Stöger, M. Heeney, F. Glöcklhofer* (# contributed equally)

J. Org. Chem. 2020, 85, 8240-8244. DOI:10.1021/acs.joc.0c00826

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.

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22. Switching between Local and Global Aromaticity in a Conjugated Macrocycle for High-Performance Organic Sodium-Ion Battery Anodes [Link, open access]

S. Eder,# D.-J. Yoo,# W. Nogala, M. Pletzer, A. Santana Bonilla, A. J. P. White, K. E. Jelfs, M. Heeney, J. W. Choi,* F. Glöcklhofer* (# contributed equally)

Angew. Chem., Int. Ed. 2020, 59, 12958-12964. DOI:10.1002/anie.202003386

Angew. Chem. 2020, 132, 13058-13064. DOI:10.1002/ange.202003386

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.

21. Hydrothermal Generation of Conjugated Polymers Using the Example of Pyrrone Polymers and Polybenzimidazoles [Link, open access]

M. J. Taublaender, S. Mezzavilla, S. Thiele, F. Glöcklhofer, M. M. Unterlass*

Angew. Chem., Int. Ed. 2020, 59, 15050-15060. DOI:10.1002/anie.202000367

Angew. Chem. 2020, 132, 15160-15171. DOI:10.1002/ange.202000367

Various polyimides and polyamides have recently been prepared via hydrothermal synthesis in nothing but H2O under high‐pressure and high‐temperature conditions. However, none of the prepared polymers feature a truly conjugated polymer backbone. Here, we report on an expansion of the synthetic scope of this straightforward and inherently environmentally friendly polymerization technique to the generation of conjugated polymers. Selected representatives of two different polymer classes, pyrrone polymers and polybenzimidazoles, were generated hydrothermally. We present a mechanistic discussion of the polymer formation process as well as an electrochemical characterization of the most promising product.

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20. Core Fluorination Enhances Solubility and Ambient Stability of an IDT‐Based n‐Type Semiconductor in Transistor Devices [Link] [Repository link, open access 02/2021]

T. Hodsden, K. J. Thorley, J. Panidi, A. Basu, A. V. Marsh, H. Dai, A. J. P. White, C. Wang, W. Mitchell, F. Glöcklhofer, T. D. Anthopoulos,* M. Heeney*

Adv. Funct. Mater. 2020, 30, 2000325. DOI:10.1002/adfm.202000325

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.

2019
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19. Effect of Symmetric and Asymmetric Substitution on the Optoelectronic Properties of 9,10-Dicyanoanthracene [Link] [Preprint link, open access]

F. Glöcklhofer,*# A. Rosspeintner,*# P. Pasitsuparoad, S. Eder, J. Fröhlich, G. Angulo, E. Vauthey, F. Plasser* (# contributed equally)

Mol. Syst. Des. Eng. 2019, 4, 951-961. DOI:10.1039/c9me00040b

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18. Fast and selective post-polymerization modification of conjugated polymers using dimethyldioxirane [Link, open access]

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

Front. Chem. 2019, 7, 123. DOI:10.3389/fchem.2019.00123

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17. Thioalkyl- and Sulfone-Substituted Poly(p-Phenylene Vinylene)s [Link] [Preprint link, open access]

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

Polym. Chem. 2019, 10, 738-750.  DOI:10.1039/c8py01717d

2018
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16. Green and Rapid Hydrothermal Crystallization and Synthesis of Fully Conjugated Aromatic Compounds [Link, open access]

M. J. Taublaender, F. Glöcklhofer, M. Marchetti-Deschmann, M. M. Unterlass*

Angew. Chem., Int. Ed. 2018, 57, 12270-12274. DOI:10.1002/anie.201801277

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15. Synthesis of 1,2,5,6- and 1,4,5,8-anthracenetetrone: Building blocks for π-conjugated small molecules and polymers [Link, open access]

F. Glöcklhofer,* B. Stöger, J. Fröhlich

Synth. Commun. 2018, 48, 2358-2365. DOI:10.1080/00397911.2018.1483027

2017
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14. Extending the Scope of a New Cyanation: Design and Synthesis of an Anthracene Derivative with an Exceptionally Low LUMO Level and Improved Solubility [Link, open access]

F. Glöcklhofer,* A. J. Morawietz, B. Stöger, M. M. Unterlass, J. Fröhlich

ACS Omega 2017, 2, 1594-1600. DOI:10.1021/acsomega.7b00245

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13. Charge-transfer states in triazole linked donor–acceptor materials: strong effects of chemical modification and solvation [Link, open access]

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

Phys. Chem. Chem. Phys. 2017, 19, 18055-18067. DOI:10.1039/C7CP01664F

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12. Dicyano- and tetracyanopentacene: foundation of an intriguing new class of easy-to-synthesize organic semiconductors [Link, open access]

F. Glöcklhofer,* A. Petritz, E. Karner, M. J. Bojdys, B. Stadlober, J. Fröhlich, M. M. Unterlass

J. Mater. Chem. C 2017, 5, 2603-2610. DOI:10.1039/C7TC00143F

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11. Using Dicyanoanthracene Triflates as Superior Precursors: Modifying Properties by Sterically Hindered Aryl Substituents [Link] [Repository link, open access]

F. Glöcklhofer,* P. Kautny, P. Fritz, B. Stöger, J. Fröhlich

ChemPhotoChem 2017, 1, 51-55. DOI:10.1002/cptc.201600018

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10. Thiophene ring-fragmentation reactions: Principles and scale-up towards NLO materials [Link]

D. Lumpi,* J. Steindl, S. Steiner, V. Carl, P. Kautny, M. Schön, F. Glöcklhofer, B. Holzer, B. Stöger, E. Horkel, C. Hametner, G. Reider, M. D. Mihovilovic, J. Fröhlich

Tetrahedron 2017, 73, 472-480. DOI:10.1016/j.tet.2016.12.025

2016
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9. A Versatile One-Pot Access to Cyanoarenes from ortho- and para-Quinones: Paving the Way for Cyanated Functional Materials [Link]

F. Glöcklhofer,* M. Lunzer, B. Stöger, J. Fröhlich

Chem. - Eur. J. 2016, 22, 5173-5180. DOI:10.1002/chem.201600004

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8. cis,trans,cis-1,2,3,4-Tetrakis[2-(ethylsulfanyl)phenyl]cyclobutane [Link]

B. Sohr, F. Glöcklhofer, B. Stöger, M. Weil, J. Fröhlich

IUCrData 2016, 1, x152426. DOI:10.1107/S2414314615024268

2013 - 2015
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7. Facile Synthesis of Cyanoarenes from Quinones by Reductive Aromatization of Cyanohydrin Intermediates [Link]

F. Glöcklhofer,* M. Lunzer, J. Fröhlich

Synlett 2015, 26, 950-952. DOI:10.1055/s-0034-1380150

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6. Towards continuous junction (CJ) organic electronic devices: Fast and clean post-polymerization modification by oxidation using dimethyldioxirane (DMDO) [Link]

F. Glöcklhofer, D. Lumpi,* M. Kohlstädt, O. Yurchenko, U. Würfel, J. Fröhlich

React. Funct. Polym. 2015, 86, 16-26. DOI:10.1016/j.reactfunctpolym.2014.10.006

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5. Multigram synthesis of bis[(trimethylsilyl) ethynyl]benzenes suitable for post-polymerization modification [Link]

F. Glöcklhofer, D. Lumpi,* B. Stöger, J. Fröhlich

New J. Chem. 2014, 38, 2229-2232. DOI:10.1039/C4NJ00011K

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4. Crystal structure of trans-1,4-bis[(trimethylsilyl) oxy]cyclohexa-2,5-diene-1,4-dicarbonitrile [Link]

F. Glöcklhofer, J. Fröhlich, B. Stöger, M. Weil*

Acta Crystallogr., Sect. E 2014, 70, 77-79. DOI:10.1107/S1600536814014251

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3. Crystal structures of 2,5-diazido-1,4-phenylene diacetate and 2,5-diazido-1,4-phenylene dibutyrate [Link]

F. Glöcklhofer, J. Fröhlich, B. Stöger, M. Weil*

Acta Crystallogr., Sect. E 2014, 70, 39-42. DOI:10.1107/S1600536814013762

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2. Systematic Investigations on 1,2,3-Triazole-Based Compounds Capable of Second Harmonic Generation [Link]

D. Lumpi,* F. Glöcklhofer, B. Holzer, B. Stöger, C. Hametner, G. A. Reider, J. Fröhlich

Cryst. Growth Des. 2014, 14, 1018-1031. DOI:10.1021/cg4014762

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1. Practical and Efficient Large-Scale Preparation of Dimethyldioxirane [Link]

H. Mikula,* D. Svatunek, D. Lumpi, F. Glöcklhofer, C. Hametner, J. Fröhlich

Org. Process Res. Dev. 2013, 17, 313-316. DOI:10.1021/op300338q

PRESENTATIONS

Presentations at conferences and symposia (not including poster presentations)

15th International Conference on Organic Electronics (ICOE2019), Hasselt, Belgium, 2019.

Talk: Room-temperature post-polymerization modification turning electron-rich into electron-poor conjugated polymers.

 

Synthesis of Organic Materials Symposium, Vienna, Austria, 2018.

Invited talk: Short Synthetic Routes to π-Conjugated Compounds for Organic Electronics and Beyond.

 

Bioelectrochemistry and more, an International Workshop, Wiener Neustadt, Austria, 2018.

Short talk: Synthesis of Dithioalkyl-substituted Poly(p-phenylene vinylene)s.

 

Austrian Chemistry Days, Salzburg, Austria, 2017.

Talk: Preparation of Cyanated Aromatic Compounds from Quinones.

 

13th International Symposium on Functional π-Electron Systems (Fπ-13), Hong Kong, China, 2017.

Talk: Rational molecular design of cyanoarenes: A new synthetic method paving the way for cyanated functional materials.

 

Bioelectrochemistry and more, an International Workshop, Wiener Neustadt, Austria, 2016.

Short talk: Air-Stable Multi-Cyanated Acenes - A Novel Synthesis Paving the Way for Cyanated Functional Materials.

 

12th International Symposium on Functional π-Electron Systems (Fπ-12), Seattle, United States, 2015.

Talk: Developing continuous junction organic electronic devices - Progress from a chemical point of view.

 

Bioelectrochemistry and more, an International Workshop, Wiener Neustadt, Austria, 2015.

Short talk: Inversion Of Material Properties By Post-Polymerization Modification.

 

International Forum/Competition of Young Researchers, Saint Petersburg, Russia, 2012.

Talk: Z-(alkylthio)alkenyl-based Compounds as Organic Nonlinear Optical Materials.

Invited presentations at universities

Chalmers University of Technology, Sweden, 2019, invited by Prof. Christian Müller.

Talk: Synthesis and Room-Temperature Post-Polymerization Modification of Thioalkyl-Substituted Conjugated Polymers.

 

Imperial College London, UK, 2017, invited by Prof. Martin Heeney.

Talk: Synthesis of Cyanoarenes from Quinones: Paving the Way for Cyanated Functional Materials.

COVER GALLERY

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​© 2021 by Florian Glöcklhofer

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