2,3,4-Trihydroxy benzonitrile-based liquid crystals: Fiber forming room temperature nematic phases

Srinatha, M.K.; Poppe, Silvio; Shanker, Govindaswamy; Alaasar, Mohamed; Tschierske, Carsten

doi:10.1016/j.molliq.2020.114244

Cited by 15 publications

(1 citation statement)

References 64 publications

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“…[ 90 ] In smectics, it is the 1D periodic structure which is responsible for stabilization of freely suspended films. [ 91 ] The unexpected film formation of the Iso 1 [ * ] phase can be attributed to the dynamic network structure, [ 30 ] which, like in the case of polymers (and some oligomesogens [ 92 ] ), stabilizes the films and leads to a non‐Newtonian behavior. Additionally, correlation of the nano clusters can be induced by the free surfaces, similar to some nematic phases forming dynamic metastable films.…”

Section: Resultsmentioning

confidence: 99%

Swallow‐Tailed Polycatenars: Controlling Complex Liquid Crystal Self‐Assembly and Mirror Symmetry Breaking at the Lamellae‐Network Cross‐Over

Reppe

Dressel

Poppe

et al. 2020

Advanced Optical Materials

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molecules in soft self-organized supramolecular systems. [1,2] Extended π-conjugated systems are also of significant interest for application as charge carrier in organic semiconductors, [3] luminescent materials (e.g., AIEgens), [4] and for circular polarized emission in helical assemblies. [5] Therefore, tuning the organization of these π-conjugated rods in soft matter systems is fundamental and requires the understanding of their general design rules. Liquid crystals (LCs) are of great interest as stimuli-responsive and switchable optical materials in displays, photo nics [6] and in sensor applications. [7,8] Rod-like π-conjugated molecules with multiple end-chains, the so-called polycatenar molecules, have received significant interests as they provide a huge variety of different LC phases ranging from lamellar (smectic, Sm) via bicontinuous cubic (Cub bi) to columnar (Col) [9-11] and even micellar cubic phases. [3] This observation has contributed to the recognition of the importance of nano-segregation for LC phase formation and demonstrated the similarity of the fundamental self-assembly principles in lyotropic systems formed by amphiphiles, in LC phases and in the solid state morphologies of block copolymers. [12,13] Among the self-assembled structures of polycatenar molecules, the Cub bi phases [14,15] received special attention because of their potential for applications, as for example in 3D conducting [16] and photonic materials, [17] being the result of their interwoven net-* ]) as well. This work establishes rules for controlling the self-assembly of functional π-conjugated rods in soft matter and fluids.

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Section: Resultsmentioning

confidence: 99%

Swallow‐Tailed Polycatenars: Controlling Complex Liquid Crystal Self‐Assembly and Mirror Symmetry Breaking at the Lamellae‐Network Cross‐Over

Reppe

Dressel

Poppe

et al. 2020

Advanced Optical Materials

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Redox‐Mediated Amination of Pyrogallol‐Based Polyphenols

Ashirbaev,

Brás,

Frei

et al. 2024

Chemistry A European J

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Flavonoids are known to covalently modify amyloidogenic peptides by amination reactions. The underlying coupling process between polyphenols and N‐nucleophiles is assessed by several in vitro and in silico approaches. The coupling reaction involves a sequence of oxidative dearomatization, amination, and reductive amination (ODARA) reaction steps. The C6‐regioselectivity of the product is confirmed by crystallographic analysis. Under aqueous conditions, the reaction of baicalein with lysine derivatives yields C‐N coupling as well as hydrolysis products of transient imine intermediates. The observed C‐N coupling reactions work best for flavonoids combining a pyrogallol substructure with an electron‐withdrawing group attached to the C4a‐position. Thermodynamic properties such as bond dissociation energies also highlight the key role of pyrogallol units for the antioxidant ability. Combining the computed electronic properties and in vitro antioxidant assays suggests that the studied pyrogallol‐containing flavonoids act by various radical‐scavenging mechanisms working in synergy. Multivariate analysis indicates that a small number of descriptors for transient intermediates of the ODARA process generates a model with excellent performance (r=0.93) for the prediction of cross‐coupling yields. The same model has been employed to predict novel antioxidant flavonoid‐based molecules are considered as potential covalent inhibitors, opening a new avenue to the design of therapeutically relevant anti‐amyloid compounds.

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