scholarly journals Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding

2021 ◽  
Vol 17 ◽  
pp. 124-131
Author(s):  
Subrata Nath ◽  
Alexander Kappelt ◽  
Matthias Spengler ◽  
Bibhisan Roy ◽  
Jens Voskuhl ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Solid State ◽  
Bond Strength ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Systematic Variation ◽  
Mesomorphic Properties

The first example of halogen-bonded fluorescent liquid crystals based on the interaction of iodofluorobenzene derivatives with nitro-cyanostilbenes is reported. The systematic variation of the fluorination degree and pattern indicates the relevance of the halogen bond strength for the induction of liquid crystalline properties. The modular self-assembly approach enables the efficient tuning of the fluorescence behaviour and mesomorphic properties of the assemblies.

Cyclic networks of halogen-bonding interactions in molecular self-assemblies: a theoretical N—X...NversusC—X...N investigation

2017 ◽  
Vol 73 (2) ◽  
pp. 179-187
Author(s):  
Ruben D. Parra ◽  
Álvaro Castillo
Keyword(s):  
Electron Density ◽  
Self Assembly ◽  
Metal Ion ◽  
Halogen Atom ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Nbo Analysis ◽  
Binding Energies ◽  
Cyclic Network ◽  
Ability To Drive

The geometries and energetics of molecular self-assembly structures that contain a sequential network of cyclic halogen-bonding interactions are investigated theoretically. The strength of the halogen-bonding interactions is assessed by examining binding energies, electron charge transfer (NBO analysis) and electron density at halogen-bond critical points (AIM theory). Specifically, structural motifs having intramolecular N—X...N (X= Cl, Br, or I) interactions and the ability to drive molecular self-assemblyviathe same type of interactions are used to construct larger self-assemblies of up to three unit motifs. N—X...N halogen-bond cooperativity as a function of the self-assembly size, and the nature of the halogen atom is also examined. The cyclic network of the halogen-bonding interactions provides a suitable cavity rich in electron density (from the halogen atom lone pairs not involved in the halogen bonds) that can potentially bind an electron-deficient species such as a metal ion. This possibility is explored by examining the ability of the N—X...N network to bind Na+. Likewise, molecular self-assembly structures driven by the weaker C—X...N halogen-bonding interactions are investigated and the results compared with those of their N—X...N counterparts.

scholarly journals Halogen bonding, chalcogen bonding, pnictogen bonding, tetrel bonding: origins, current status and discussion

2017 ◽  
Vol 203 ◽  
pp. 485-507 ◽  
Author(s):  
Lee Brammer
Keyword(s):  
Solid State ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Main Group ◽  
Solution Phase ◽  
Current Status ◽  
Solid State Chemistry ◽  
Main Group Elements ◽  
Past Work

The role of the closing lecture in a Faraday Discussion is to summarise the contributions made to the Discussion over the course of the meeting and in so doing capture the main themes that have arisen. This article is based upon my Closing Remarks Lecture at the 203rdFaraday Discussion meeting on Halogen Bonding in Supramolecular and Solid State Chemistry, held in Ottawa, Canada, on 10–12thJuly, 2017. The Discussion included papers on fundamentals and applications of halogen bonding in the solid state and solution phase. Analogous interactions involving main group elements outside group 17 were also examined. In the closing lecture and in this article these contributions have been grouped into the four themes: (a) fundamentals, (b) beyond the halogen bond, (c) characterisation, and (d) applications. The lecture and paper also include a short reflection on past work that has a bearing on the Discussion.

Synthesis and Mesomorphic Properties of New Liquid Crystalline Cyclohexyl-phenyl- and Dicyclohexyl-pyrimidines

1979 ◽  
Vol 34 (11) ◽  
pp. 1535-1541 ◽  
Author(s):  
Alois Villiger ◽  
Arthur Boiler ◽  
Martin Schadt
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Viscosity Reduction ◽  
Refractive Indices ◽  
Thermal Compatibility ◽  
Chain Lengths ◽  
New Compounds ◽  
Mesomorphic Properties ◽  
End Group

Abstract Liquid Crystals, Cyclohexyl-phenyl-pyrimidines, Dicyclohexyl-pyrimidines The synthesis and mesomorphic properties of three new classes of cyano-substituted cyclohexyl-phenyl-and dicyclohexyl-pyrimidines are reported. The compounds are colourless, chemically and photochemically stable and have wide nematic mesophases. The thermal compatibility of the new compounds with other nematic liquid crystals is excellent. The large static positive dielectric anisotropics are shown to depend strongly on the position and number of hydrogenated rings as well as on the alkyl chain lengths within a homologous series. The reported bulk viscosities vary considerably among homologues. Hydrogenating the ring adjacent to the cyano end group causes η to increase, whereas a considerable viscosity reduction compared to nonhydrogenated homologues was found by hydrogenating the ring adjacent to the alkyl end group. The measured refractive indices of the new compounds are comparable to those of biphenyls.

scholarly journals Characterizing the interplay of Pauli repulsion, electrostatics, dispersion and charge transfer in halogen bonding with energy decomposition analysis

2018 ◽  
Vol 20 (2) ◽  
pp. 905-915 ◽  
Author(s):  
Jonathan Thirman ◽  
Elric Engelage ◽  
Stefan M. Huber ◽  
Martin Head-Gordon
Keyword(s):  
Charge Transfer ◽  
Bond Strength ◽  
Halogen Bond ◽  
Decomposition Analysis ◽  
Halogen Bonding ◽  
Energy Decomposition Analysis ◽  
Energy Decomposition ◽  
Pauli Repulsion

Variational energy decomposition analysis establishes charge-transfer as the origin of halogen bond strength differences that go against electrostatics.

Halogen bonding two-point recognition with terphenyl derivatives

2018 ◽  
Vol 42 (13) ◽  
pp. 10476-10480 ◽  
Author(s):  
J. Stoesser ◽  
G. Rojas ◽  
D. Bulfield ◽  
P. I. Hidalgo ◽  
J. Pasán ◽  
...  
Keyword(s):  
Solid State ◽  
Halogen Bond ◽  
Halogen Bonding

Neutral terphenyl-based halogen bond donors form two-point halogen bonding motifs with oxadiazoles in the solid state.

Supramolecular assembly in metal complexes: Two structural cases

2013 ◽  
Vol 85 (2) ◽  
pp. 397-404 ◽  
Author(s):  
Mohamed Ghazzali
Keyword(s):  
Solid State ◽  
Self Assembly ◽  
Theoretical Calculations ◽  
Supramolecular Assembly ◽  
Halogen Bonding ◽  
One Pot ◽  
Iron Coordination ◽  
Structural Database ◽  
Molecular Components ◽  
Theoretical Analyses

With the current advances in our understanding of molecular components in the solid-state world, the relation between energy and geometry remains controversial. In this study, we deliver a concise account for supramolecular chemistry, and in order to illustrate some of its concepts we describe some structural and theoretical analyses for two unique cases of our work. We elaborate on a supramolecular model of controlled “one-pot” host–guest metal-mediated self-assembly reaction inside iron coordination polymer grid architecture, and we review halogen bonding by specifically observing M–Cl···Cl–M intermolecular interactions using Cambridge Structural Database (CSD) hit analyses with theoretical calculations.

Self-assembled blue-light emitting materials for their liquid crystalline and OLED applications: from a simple molecular design to supramolecular materials

2020 ◽  
Vol 5 (10) ◽  
pp. 1691-1705
Author(s):  
Vinay S. Sharma ◽  
Anuj S. Sharma ◽  
Nikhil K. Agarwal ◽  
Priyanka A. Shah ◽  
Pranav S. Shrivastav
Keyword(s):  
Liquid Crystals ◽  
Blue Light ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Molecular Design ◽  
Supramolecular Materials ◽  
Light Emitting ◽  
New Family ◽  
Self Assembled

A new family of blue-light-emitting supramolecular bowl-shaped columnar hexagonal liquid crystals based on p-tert-butylcalix[4]arene and functionalized via chalconyl–ester-linked biphenyl amine derivatives form a self-assembly and their applications.

scholarly journals In Situ Assessment of Intrinsic Strength of X-I⋯OA-Type Halogen Bonds in Molecular Crystals with Periodic Local Vibrational Mode Theory

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1589 ◽  
Author(s):  
Yunwen Tao ◽  
Yue Qiu ◽  
Wenli Zou ◽  
Sadisha Nanayakkara ◽  
Seth Yannacone ◽  
...  
Keyword(s):  
Bond Strength ◽  
Vibrational Mode ◽  
Halogen Bond ◽  
Molecular Crystals ◽  
Halogen Bonding ◽  
Halogen Bonds ◽  
Mode Theory ◽  
Local Vibrational Mode ◽  
Intrinsic Strength

Periodic local vibrational modes were calculated with the rev-vdW-DF2 density functional to quantify the intrinsic strength of the X-I⋯OA-type halogen bonding (X = I or Cl; OA: carbonyl, ether and N-oxide groups) in 32 model systems originating from 20 molecular crystals. We found that the halogen bonding between the donor dihalogen X-I and the wide collection of acceptor molecules OA features considerable variations of the local stretching force constants (0.1–0.8 mdyn/Å) for I⋯O halogen bonds, demonstrating its powerful tunability in bond strength. Strong correlations between bond length and local stretching force constant were observed in crystals for both the donor X-I bonds and I⋯O halogen bonds, extending for the first time the generalized Badger’s rule to crystals. It is demonstrated that the halogen atom X controlling the electrostatic attraction between the σ -hole on atom I and the acceptor atom O dominates the intrinsic strength of I⋯O halogen bonds. Different oxygen-containing acceptor molecules OA and even subtle changes induced by substituents can tweak the n → σ ∗ (X-I) charge transfer character, which is the second important factor determining the I⋯O bond strength. In addition, the presence of the second halogen bond with atom X of the donor X-I bond in crystals can substantially weaken the target I⋯O halogen bond. In summary, this study performing the in situ measurement of halogen bonding strength in crystalline structures demonstrates the vast potential of the periodic local vibrational mode theory for characterizing and understanding non-covalent interactions in materials.

scholarly journals Halogen Bonding in the Complexes of Brominated Electrophiles with Chloride Anions: From a Weak Supramolecular Interaction to a Covalent Br–Cl Bond

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1075
Author(s):  
Cody Loy ◽  
Matthias Zeller ◽  
Sergiy V. Rosokha
Keyword(s):  
Bond Strength ◽  
Halogen Bond ◽  
Covalent Bond ◽  
Halogen Bonding ◽  
Halogen Bonds ◽  
Nucleophilic Reaction ◽  
X Ray ◽  
Wide Range ◽  
Judicious Choice ◽  
Range Variation

The wide-range variation of the strength of halogen bonds (XB) not only facilitates a variety of applications of this interaction, but it also allows examining the relation (and interconversion) between supramolecular and covalent bonding. Herein, the Br…Cl halogen bonding in a series of complexes of bromosubstituted electrophiles (R-Br) with chloride anions were examined via X-ray crystallographic and computational methods. Six co-crystals showing such bonding were prepared by evaporation of solutions of R-Br and tetra-n-propylammonium chloride or using Cl− anions released in the nucleophilic reaction of 1,4-diazabicyclo[2.2.2]octane with dichloromethane in the presence of R-Br. The co-crystal comprised networks formed by 3:3 or 2:2 halogen bonding between R-Br and Cl−, with the XB lengths varying from 3.0 Å to 3.25 Å. Analysis of the crystallographic database revealed examples of associations with substantially longer and shorter Br…Cl separations. DFT computations of an extended series of R–Br…Cl− complexes confirmed that the judicious choice of brominated electrophile allows varying halogen Br…Cl bond strength and length gradually from the values common for the weak intermolecular complexes to that approaching a fully developed covalent bond. This continuity of halogen bond strength in the experimental (solid-state) and calculated associations indicates a fundamental link between the covalent and supramolecular bonding.

scholarly journals Revealing molecular self-assembly and geometry of non-covalent halogen bonding by solid-state NMR spectroscopy

2008 ◽  
pp. 5981 ◽  
Author(s):  
Markus Weingarth ◽  
Noureddine Raouafi ◽  
Benjamin Jouvelet ◽  
Luminita Duma ◽  
Geoffrey Bodenhausen ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Self Assembly ◽  
Solid State Nmr ◽  
Halogen Bonding ◽  
Solid State Nmr Spectroscopy
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