CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• Cheng [63] designed a click inspired synthesis of novel discotic mesogen bearing a porphyrin unit, a triazole linkage, and a peripheral 3,4,5-trialkoxybenzyl unit (Scheme 32). Firstly, free-base porphyrin conjugates 151a–c were obtained by the CuAAC reaction between metal free tetraalkynylporphyrin 149

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• polydispersity index PDI = 1.23. The possibility of employing ROMP as a key step in the synthesis of a polynorbornene-based mesogen-jacketed liquid crystalline polymer (MJLCP) containing polyhedral oligomeric silsesquioxane (POSS) in the side chain was demonstrated by Shen and Fan (Scheme 28) [52]. The reaction

The influence of intraannular templates on the liquid crystallinity of shape-persistent macrocycles

• Joscha Vollmeyer,
• Ute Baumeister and
• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 910–920, doi:10.3762/bjoc.10.89

• 1c, the length of the template seems to be similar to the alkyl template in 1a. However, the tendency of oligoethylene oxides to obtain a helical conformation [55] may fold the arylene–acetylene backbone into a boat conformation which is no longer a discotic mesogen. For the macrocycles 2a–d, the

Unusual polymorphism in new bent-shaped liquid crystals based on biphenyl as a central molecular core

• Anna Kovářová,
• Svatopluk Světlík,
• Václav Kozmík,
• Jiří Svoboda,
• Vladimíra Novotná,
• Damian Pociecha,
• Ewa Gorecka and
• Natalia Podoliak

Beilstein J. Org. Chem. 2014, 10, 794–807, doi:10.3762/bjoc.10.75

• properties, and columnar phases have been found for all compounds. A unique phase sequence has been found for the mesogen with the fluorinated chain. A generalized tilted smectics, SmCG, have been observed in a temperature interval between two different lamellar SmCP phases and characterized by X-ray and

Formation of smectic phases in binary liquid crystal mixtures with a huge length ratio

• Nadia Kapernaum,
• Friederike Knecht,
• C. Scott Hartley,
• Jeffrey C. Roberts,
• Robert P. Lemieux and
• Frank Giesselmann

Beilstein J. Org. Chem. 2012, 8, 1118–1125, doi:10.3762/bjoc.8.124

• phase of the longer mesogen was identified as a smectic F phase. Keywords: bidispersity; liquid crystals; phase diagrams; smectic phases; smectic F phase; structure and dynamics; Introduction The mixing of different liquid crystals is a common technique to tailor their properties for specific

• measured at a field strength of 12.5 V·μm−1. Smectic A phase of a mixture of two mesogens differing strongly in molecular length. Left: The layer spacing corresponds to the length of the long mesogen; no out-of-layer fluctuations occur. This leads to a lot of unfavorable free volume. Right: By reducing the

• smectic translational order the molecules are now densely packed. This leads to extensive out-of-layer fluctuations. Reproduced after [1]. Molecular structures and molecular lengths of 2PhP and PhP16. The longer mesogen PhP16 is approximately twice the length of the shorter mesogen 2PhP. The energy of

Liquid-crystalline heterodimesogens and ABA-heterotrimesogens comprising a bent 3,5-diphenyl-1,2,4-oxadiazole central unit

• Govindaswamy Shanker,
• Marko Prehm and
• Carsten Tschierske

Beilstein J. Org. Chem. 2012, 8, 472–485, doi:10.3762/bjoc.8.54

• laterally [44], or combining a bent-core segment with a rod-shaped mesogen [40][45][46][47][48][49][50][51][52][53][54], and related end-to-end connected ABA-heterotrimesogens combining a bent-core segment with two rod-like units [55], or a rod-like core with two bent-core units [56], were synthesized and

• trimesogens were obtained by following the synthetic protocols described in Scheme 2 and Scheme 3 by DCC coupling of the ω-mesogen-functionalized alkanoic acids 2 [66] and 4 [66] with 4-[(4-hydroxyphenyl)-1,2,4-oxadiazol-5-yl]phenyl 4-hexylbenzoate (3) [67] and 3,5-bis(4-hydroxyphenyl)-1,2,4-oxadiazole (1

• are more decoupled, the reduction of the tilt is much less (37–39° tilt). Hence, not only the type of rod-like mesogen, but also the degree of coupling of the rod-like units to the 3,5-diphenyl-1,2,4-oxadiazole core, seems to be important for the degree of tilt. Distinguishing skewed and orthogonal

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

• Gareth L. Nealon,
• Romain Greget,
• Cristina Dominguez,
• Zsuzsanna T. Nagy,
• Daniel Guillon,
• Jean-Louis Gallani and
• Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

• organic ligand coating and their resulting phase behaviour. Mechanisms proposed to explain the supramolecular organisation of the mesogens within the liquid-crystalline phases are discussed. Keywords: hybrid; liquid crystal; mesogen; mesomorphism; mesophase; nanoparticle; self-organisation; supramolecule

• presence of a solvent are known as lyotropic. A material that exhibits LC properties is referred to as a mesogen and is said to exhibit mesomorphism; although something that is mesogenic (e.g., proto-mesogens) is not necessarily mesomorphic. Thermotropic liquid crystals are usually formed by molecules that

• , based on the shape and chemical characteristics of the mesogen under investigation. The simplest is the nematic phase, whereby the mesogenic moieties exhibit an average alignment along a common direction (or director), whereas the smectic phases also display a degree of positional ordering (i.e., the

Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

• Sonja Findeisen-Tandel,
• Wolfgang Weissflog,
• Ute Baumeister,
• Gerhard Pelzl,
• H. N. Shreenivasa Murthy and
• Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

• nematic phase is observed, which is very surprising for this mesogen having a molecular shape characteristic of banana-shaped liquid crystals. Although both legs of the bent-core molecules are extended by the C=C units, the clearing temperatures increase only by about 10 K. Introduction of a lateral

Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules

• Matthias Lehmann and
• Jens Seltmann

Beilstein J. Org. Chem. 2009, 5, No. 73, doi:10.3762/bjoc.5.73

• temperature range nematic. For the optimised mesogen structure, optical investigations by conoscopy monitored a uniaxial nematic phase upon cooling from the isotropic phase to room temperature (ΔT = 150 °C). X-ray studies on magnetic-field-aligned samples of this mesogen family revealed a general pattern

• design a shape-persistent molecular scaffold of type I (Figure 2) based on oligo(phenylene ethynylene) building blocks. These molecules show liquid crystal behaviour only with a flat bending unit possessing a dipole along the apex of the mesogen, sufficiently long aliphatic chains R and at least one

• the molecular long axis, on which the different spacer length should have the largest impact, remain constant between 9 and 10 Å. The latter can be rationalised when the electron-poor thiadiazole units interact with the electron-rich 2,5-dialkyloxybenzenes of an antiparallel aligned mesogen. As

Molecular length distribution and the formation of smectic phases

• Nadia Kapernaum,
• C. Scott Hartley,
• Jeffrey C. Roberts,
• Robert P. Lemieux and
• Frank Giesselmann

Beilstein J. Org. Chem. 2009, 5, No. 65, doi:10.3762/bjoc.5.65

• mixtures of chemically similar smectogenic mesogens strongly differing in molecular length were investigated. In these mixtures the nematic phase present in the pure short mesogen disappeared rapidly on the addition of the longer mesogen, while the smectic state was preserved. In the smectic state the

1-(4-Alkyloxybenzyl)-3-methyl-1H-imidazol-3-ium organic backbone: A versatile smectogenic moiety

• William Dobbs,
• Laurent Douce and
• Benoît Heinrich

Beilstein J. Org. Chem. 2009, 5, No. 62, doi:10.3762/bjoc.5.62

• spacing. This evidence is the consequence of the evolution of the projection area of a mesogen counter-ion assembly within the mean smectic plane, the thickness of the aliphatic sublayer variating in proportion since the spreading of the liquid alkyl chains occurs without volume variation [31]. This

• projection area, called "molecular area" S, is equal to the ratio N·Vmol/d, in which d is the layer spacing, Vmol the molecular volume and N the number of superposed mesogen counter-ion assemblies in the ionic sublayer. Thus, the alkyl tails expelled from each side of the sublayer containing the ions and the

Coaxial electrospinning of liquid crystal-containing poly(vinylpyrrolidone) microfibres

• Eva Enz,
• Ute Baumeister and
• Jan Lagerwall

Beilstein J. Org. Chem. 2009, 5, No. 58, doi:10.3762/bjoc.5.58

• encapsulated liquid crystal, most likely due to mesogen anchoring without positional order at the inner surface of the polymer sheath. So, after heating into the isotropic phase, on subsequent cooling the smectic phase cannot be formed immediately even though it is the thermodynamically stable phase at room

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

• Alessandra Crispini,
• Mauro Ghedini and
• Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

• -diketonates. Molecular structure of Pt(II) complexes based on 4,4′-disubstituted 2,2′-bipyridines. Molecular structure of Zn(II) complexes based on polycatenar 4,4′-disubstituted 2,2′-bipyridines. Molecular structure of a gallium(III) mesogen. Acknowledgments Financial support received from the Ministero

A convenient method for preparing rigid-core ionic liquid crystals

• Julien Fouchet,
• Laurent Douce,
• Benoît Heinrich,
• Richard Welter and
• Alain Louati

Beilstein J. Org. Chem. 2009, 5, No. 51, doi:10.3762/bjoc.5.51

• both phases. The observed layer thickness change is therefore the consequence of the different “molecular areas” S, i.e. the projection area of a mesogen counter-ion assembly within the mean smectic plane (S = 2Vmol/d), which is identical to the lattice area in the crystalline phase (S = V/d001). Thus