0000000001303524
AUTHOR
Christoph Wölper
On the blue phase structure of hydrogen-bonded liquid crystals via 19F NMR
Abstract 19 F NMR spectra are simulated for blue phase I of FPHG( St 1.5 ∗ Ap 1.5 ) based on a model of a double-twisted substructure inside cylinders that form a body-centred cubic lattice. A kinetic matrix is included to describe jump processes over quarter pitch lengths. Though the lines in the NMR spectra are broad and featureless, changes in the widths and positions with temperature are well described by the blue phase model structure. The spectra in the chiral nematic N∗ phase are also simulated. Dynamics in the BP I are found to be slower than in the N∗ phase.
Cover Feature: Excited‐State Kinetics of an Air‐Stable Cyclometalated Iron(II) Complex (Chem. Eur. J. 51/2019)
Improving the mesomorphic behaviour of supramolecular liquid crystals by resonance-assisted hydrogen bonding
A systematic structure-property relationship study on hydrogen-bonded liquid crystals was performed, revealing the impact of resonance-assisted hydrogen bonds (RAHBs) on the self-assembling behavior of the supramolecular architecture. The creation of a six-membered intramolecular hydrogen-bonded ring acts as a counterpart to the self-organization between hydrogen bond donators and acceptors and determines thus the suprastructure. Variation of the hydrogen-bonding pattern allowed us to significantly improve the temperature range of the reported liquid crystalline assemblies.
Naturally occurring polyphenols as building blocks for supramolecular liquid crystals – substitution pattern dominates mesomorphism
A modular supramolecular approach towards hydrogen-bonded liquid crystalline assemblies based on naturally occurring polyphenols is reported. The combination of experimental observations, crystallographic studies and semi-empirical analyses of the assemblies provides insight into the structure–property relationships of these materials. Here a direct correlation of the number of donor OH-groups as well as their orientation with the mesomorphic behavior is reported. We discovered that the number and orientation of the OH-groups have a stronger influence on the mesomorphic behavior of the supramolecular assemblies than the connectivity (e.g. stilbenoid or chalconoid) of the hydrogen bond donor…
A modular approach towards functional supramolecular aggregates - subtle structural differences inducing liquid crystallinity.
Herein we report an efficient modular approach to supramolecular functional materials. Hierarchical self-assembly of azopyridine derivatives and hydrogen-bond donors yielded discotic assemblies. Subtle differences in the core units introduced mesomorphic behaviour and fast photo-response of the liquid crystals based on phloroglucinol. The presented results prove the benefits of a modular methodology towards highly responsive materials with tailor-made properties.
Photoresponsive Halogen-Bonded Liquid Crystals: The Role of Aromatic Fluorine Substitution
A new strategy for controlling the liquid crystalline and photophysical properties of supramolecular mesogens assembled via halogen bonding is reported. Changing the degree of fluorination at the halogen-bond donor of the supramolecular liquid crystal allows for the fine-tuning of the halogen bond strength and thereby provides control over the temperature range of the mesophase. At least three fluorine atoms have to be present to ensure efficient polarization of the halogen-bond donor and the formation of a mesophase. In addition, it was found that stilbazole acceptors are superior to their azopyridine counterparts in promoting stable liquid crystalline phases. The halogen-bond-driven supra…
Alkylated Aromatic Thioethers with Aggregation‐Induced Emission Properties—Assembly and Photophysics
In this contribution, we present the synthesis and self-assembly of alkylated thioethers with interesting photophysical properties. To this end, the emission, absorption and excitation spectra in organic solvents and as aggregates in water were measured as well as the corresponding photoluminescence quantum yields and lifetimes. The aggregates in aqueous media were visualized and measured using transmission electron microscopy. Besides that, crystal structures of selected compounds allowed a detailed discussion of the structure–property relationship. Furthermore, the mesomorphic behavior was investigated using polarized optical microscopy (POM) as well as differential scanning calorimetry (…
Excited-State Kinetics of an Air-Stable Cyclometalated Iron(II) Complex.
The complex class [Fe(N^N^C)(N^N^N)]+ with an Earth-abundant metal ion has been repeatedly suggested as a chromophore and potential photosensitizer on the basis of quantum chemical calculations. Synthesis and photophysical properties of the parent complex [Fe(pbpy)(tpy)]+ (Hpbpy=6-phenyl-2,2'-bipyridine and tpy=2,2':6',2''-terpyridine) of this new chromophore class are now reported. Ground-state characterization by X-ray diffraction, electrochemistry, spectroelectrochemistry, UV/Vis, and X-ray spectroscopy in combination with DFT calculations proves the high impact of the cyclometalating ligand on the electronic structure. The photophysical properties are significantly improved compared to …
Structure-property relationships in aromatic thioethers featuring aggregation-induced emission : Solid-state structures and theoretical analysis
We describe in this paper a structure–property relationship study of aromatic thioethers with aggregation-induced emission (AIE) properties. We combine a structural analysis based on geometrical consideration with an in-depth analysis of the crystalline packing supported by quantum mechanical calculations. Our results allow us to correlate the enhanced fluorescence quantum yields with the significant increase of C–H⋯π and the decrease of π⋯π interactions in the solid state – a result which supports the well-accepted AIE mechanism quantitatively.
Photo-switching and -cyclisation of hydrogen bonded liquid crystals based on resveratrol
A series of hydrogen-bonded liquid crystals based on resveratrol and resveratrone is reported and investigated with respect to their photo-switchability (at 405 nm) and photo-cyclisation (at 300 nm).
Chiral mesophases of hydrogen-bonded liquid crystals
The chiral induction in hydrogen-bonded liquid crystals is investigated. The experimental study was accompanied by detailed density functional theory calculations and variable-temperature solid-state deuteron NMR measurements indicating that interactions between the linking groups of the hydrogen-bond accepting unit play a key role in the chiral induction.
CCDC 1866422: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Matthias Spengler, Michael Pfletscher, Kim Kuntze, Matti Virkki, Christoph Wölper, Robert Gehrke, Georg Jansen, Pierangelo Metrangolo, Arri Priimagi, Michael Giese|2019|Chem.Mater.|31|462|doi:10.1021/acs.chemmater.8b04197
CCDC 1894901: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Steffen Riebe, Jacqueline Stelzer, Christoph Wölper, Constantin G. Daniliuc, Jens Voskuhl, Michael Giese|2019|CrystEngComm|21|3097|doi:10.1039/C9CE00444K
CCDC 1939466: Experimental Crystal Structure Determination
Related Article: Meik Blanke, Jan Balszuweit, Marco Saccone, Christoph Wölper, David Doblas Jiménez, Markus Mezger, Jens Voskuhl, Michael Giese|2020|Chem.Commun.|56|1105|doi:10.1039/C9CC07721A
CCDC 1893331: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Steffen Riebe, Jacqueline Stelzer, Christoph Wölper, Constantin G. Daniliuc, Jens Voskuhl, Michael Giese|2019|CrystEngComm|21|3097|doi:10.1039/C9CE00444K
CCDC 1895359: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Steffen Riebe, Jacqueline Stelzer, Christoph Wölper, Constantin G. Daniliuc, Jens Voskuhl, Michael Giese|2019|CrystEngComm|21|3097|doi:10.1039/C9CE00444K
CCDC 1886744: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Michael Pfletscher, Sven Kather, Christoph Wölper, Constantin Daniliuc, Markus Mezger, Michael Giese|2019|J.Mater.Chem.C|7|8643|doi:10.1039/C9TC02787D
CCDC 1939467: Experimental Crystal Structure Determination
Related Article: Meik Blanke, Jan Balszuweit, Marco Saccone, Christoph Wölper, David Doblas Jiménez, Markus Mezger, Jens Voskuhl, Michael Giese|2020|Chem.Commun.|56|1105|doi:10.1039/C9CC07721A
CCDC 1895424: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Steffen Riebe, Jacqueline Stelzer, Christoph Wölper, Constantin G. Daniliuc, Jens Voskuhl, Michael Giese|2019|CrystEngComm|21|3097|doi:10.1039/C9CE00444K
CCDC 1866421: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Matthias Spengler, Michael Pfletscher, Kim Kuntze, Matti Virkki, Christoph Wölper, Robert Gehrke, Georg Jansen, Pierangelo Metrangolo, Arri Priimagi, Michael Giese|2019|Chem.Mater.|31|462|doi:10.1021/acs.chemmater.8b04197
CCDC 1455700: Experimental Crystal Structure Determination
Related Article: Michael Pfletscher, Christoph Wölper, Jochen S. Gutmann, Markus Mezger, Michael Giese|2016|Chem.Commun.|52|8549|doi:10.1039/C6CC03966A
CCDC 1942435: Experimental Crystal Structure Determination
Related Article: Jan Balszuweit, Meik Blanke, Marco Saccone, Markus Mezger, Constantin G. Daniliuc, Christoph Wölper, Michael Giese, Jens Voskuhl|2021|MSDE|6|390|doi:10.1039/D0ME00171F
CCDC 1877494: Experimental Crystal Structure Determination
Related Article: Steffen Riebe, Marco Saccone, Jacqueline Stelzer, Andrea Sowa, Christoph Wölper, Kateryna Soloviova, Cristian A. Strassert, Michael Giese, Jens Voskuhl|2019|Chem.Asian J.|14|814|doi:10.1002/asia.201801564
CCDC 1871602: Experimental Crystal Structure Determination
Related Article: Steffen Riebe, Marco Saccone, Jacqueline Stelzer, Andrea Sowa, Christoph Wölper, Kateryna Soloviova, Cristian A. Strassert, Michael Giese, Jens Voskuhl|2018|CSD Communication|||
CCDC 1886743: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Michael Pfletscher, Sven Kather, Christoph Wölper, Constantin Daniliuc, Markus Mezger, Michael Giese|2019|J.Mater.Chem.C|7|8643|doi:10.1039/C9TC02787D
CCDC 1945777: Experimental Crystal Structure Determination
Related Article: Jan Balszuweit, Meik Blanke, Marco Saccone, Markus Mezger, Constantin G. Daniliuc, Christoph Wölper, Michael Giese, Jens Voskuhl|2021|MSDE|6|390|doi:10.1039/D0ME00171F
CCDC 1871491: Experimental Crystal Structure Determination
Related Article: Steffen Riebe, Marco Saccone, Jacqueline Stelzer, Andrea Sowa, Christoph Wölper, Kateryna Soloviova, Cristian A. Strassert, Michael Giese, Jens Voskuhl|2019|Chem.Asian J.|14|814|doi:10.1002/asia.201801564
CCDC 1866420: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Matthias Spengler, Michael Pfletscher, Kim Kuntze, Matti Virkki, Christoph Wölper, Robert Gehrke, Georg Jansen, Pierangelo Metrangolo, Arri Priimagi, Michael Giese|2019|Chem.Mater.|31|462|doi:10.1021/acs.chemmater.8b04197
CCDC 1904835: Experimental Crystal Structure Determination
Related Article: Jakob Steube, Lukas Burkhardt, Ayla Päpcke, Johannes Moll, Peter Zimmer, Roland Schoch, Christoph Wölper, Katja Heinze, Stefan Lochbrunner, Matthias Bauer|2019|Chem.-Eur.J.|25|11826|doi:10.1002/chem.201902488
CCDC 1895360: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Steffen Riebe, Jacqueline Stelzer, Christoph Wölper, Constantin G. Daniliuc, Jens Voskuhl, Michael Giese|2019|CrystEngComm|21|3097|doi:10.1039/C9CE00444K
CCDC 1884535: Experimental Crystal Structure Determination
Related Article: Marco Saccone, Michael Pfletscher, Sven Kather, Christoph Wölper, Constantin Daniliuc, Markus Mezger, Michael Giese|2019|J.Mater.Chem.C|7|8643|doi:10.1039/C9TC02787D