Induction of Smectic Layering in Nematic Liquid Crystals Using Immiscible Components. 5. Laterally Attached Side-Chain Liquid Crystalline Poly(norbornene)s and Their Low Molar Mass Model Compounds with Short Fluorocarbon Segments

Abstract

Bis[(4′′-n-((perfluoroalkyl)alkoxy)benzoyl)oxy]benzyl]oxy]carbonyl]bicyclo[2.2.1]hept-2-enes with short fluorocarbon segments were polymerized by ring-opening metathesis polymerization in THF at room temperature using Mo(CHCMe 2Ph)(N-2,6-i Pr2Ph)(O t Bu)2 as the initiator. Although hydrocarbon and fluorocarbon segments as short as three methylenic units each induce smectic layering in the corresponding 2,5-bis{[4′-(n-(perfluoroalkyl)alkoxy)benzoyl]oxy}toluene model compounds, the polymers require at least eight and three, or five and four methylenic units in the hydrocarbon and fluorocarbon segments, respectively, to organize into smectic layers; polymers with shorter hydrocarbon and/or fluorocarbon segments are nematic.

A New Type of Macroscopically Oriented Smectic‐A Liquid Crystal Elastomer

“…The mesogenic unit resembles that synthesized by Small and Pugh. [8] They used a non-crosslinked poly(norbonene) system and investigated the influence of perfluorinated side-chains on the LC phase behavior. Smectic phases were observed when incorporating longer perfluorinated alkyl chains at the ends of the rigid core.…”

Liquid Crystalline Polymers by Metathesis Polymerization

“…14) [76][77][78]. This route used the immiscibility of hydrocarbons with fluorocarbon segments, which was expected to force the polymer to adopt a layered structure, favoring a smectic mesophase.…”

“…In general, the melting points of the model compounds were simply replaced by a glass transition and the isotropization temperatures were about 20°C higher in the polymers than in the model compounds. In a subsequent paper, Pugh and co-workers investigated the LC properties of XXIII-n-m with short fluorocarbon endgroups, m=2-4 [78]. Monomers with the shortest fluorocarbon segment, m=2, did not show any mesophase when the hydrocarbon segment was short (n=3-5).…”

The chemistry of the carbon–transition metal double and triple bond: annual survey covering the year 2002

“…16) [139]; (7) norbornenes connected to pincer-ligated phenylpalladium(II) derivatives (e.g. 17) [140,141]; (8) norbornenes fused to the N-hydroxysuccinimide ring system [142]; (9) norbornenes and oxanorbornenes of general structure 18 [143]; (10) norbornenecarboxylate esters of complex fluorinated benzyl alcohol derivatives [144]; (11) polyethylene glycol-bound norbornenes [145]; (12) adenine-containing norbornene derivatives [146]; (13) norbornene derivatives featuring a thymidine ring associated with a 1,6-diamidopyridine derivative (19) [147]; (14) bicyclo[3.2.0]hept-6-ene [148]; (15) norbornene-fused succinimides [149]; (16) norbornenes attached to oligothiophene units (e.g. 20) [150]; (17) 3,5-siloxane-bridged cyclopentenes (e.g.…”