Über die thermische Persistenz von krystallin‐flüssigen Phasen

Weygand, C.; Gabler, R.

doi:10.1002/cber.19380711129

Cited by 32 publications

(5 citation statements)

References 6 publications

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“…16 Due to the insolubility of polymer 16 the molecular weight is limited to low values. Poly(1 ,4-phenylenevinylene) (16) can be obtained starting from 4-bromostyrene.…”

Section: Resultsmentioning

confidence: 99%

“…(14) Poiy(Z,4-phenylenevinylene) (16): 3,6 g (20 mmol) ofp-bromostyrene, 0,112 g (03 mmol) of palladium (11) acetate, 0,46 g ( 1 3 mmol) of tri-o-tolylphosphine, and 7,8 g (42 mmol) of tributylamine were dissolved in 100 ml of DMF and heated to 140 "C for 64 h under nitrogen. The product is soluble as its potassium salt.…”

Section: 4'-stilbenedicurboxylic Acid (4)mentioning

confidence: 99%

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Synthesis of monomers and polymers by the Heck reaction

Heitz¹,

Brügging²,

Freund³

et al. 1988

Makromol. Chem.

126

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The Heck reaction allows the synthesis of monomers in a one-step reaction. Catalyzed by Pd, bromoarenes are reacted with ethylene to form substituted styrenes and symmetrical stilbenes. Unsymmetrical stilbenes are obtained from substituted bromoarenes and styrenes. Substituted hydroquinones and terephthalic acids are also available in high yields. Poly(l,4-phenylenevinylene) is obtained starting from 4-bromostyrene. Experimental partA typical procedure for the synthesis of a styrene and a stilbene derivative is given. Experimental conditions for other monomers are shown in Tab. 1.Reagents: DMF: distilled over 4,4 '-methylenedi(pheny1 isocyanate) and dibutyltin dilaurate as catalyst. Pd(OAc)2: used as received (Degussa). Tri-o-tolylphosphine: synthesized according to lit. '). Triethylamine, tributylamine: distilled over KOH. Styrene: used as received (stabilized with catechol). 4-Vinylbenzamide (6):A flame-dried pressure vessel of 100 ml volume was loaded under argon with 7 g (35 mmol) of p-bromobenzamide, 0,21 g (0,7 mmol) of tri-o-tolylphosphine, 0,078 g (0,35 mmol) of palladium acetate, 5,46 ml (40 mmol) of triethylamine, and a teflon@coated stir bar. 60 ml of DMF were added and a pressure of 72 bar ethylene (room temperature) applied. The autoclave was heated to 130°C for 24 h. The reaction mixture was precipitated with 400 ml of water and the solid dissolved in acetone. The filtered solution was concentrated and the residue was purified by sublimation. Yield: 3,7 g (72%), m.p. 176-177 "C, determined by DSC (lit.5): 170°C).

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“…16 Due to the insolubility of polymer 16 the molecular weight is limited to low values. Poly(1 ,4-phenylenevinylene) (16) can be obtained starting from 4-bromostyrene.…”

Section: Resultsmentioning

confidence: 99%

Section: 4'-stilbenedicurboxylic Acid (4)mentioning

confidence: 99%

Synthesis of monomers and polymers by the Heck reaction

Heitz¹,

Brügging²,

Freund³

et al. 1988

Makromol. Chem.

126

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show abstract

“…The smectic phases of the higher homologues of this series are all SA (simple focal-conic or homeotropic textures, complete miscibility with the SA phase of series I). The mesophases of the p,p'-di-n-alkoxyazoxybenzenes are described in references [18] and [23]. The In order to investigate whether the asymmetric shape of the molecules affects certain mesophases, we finally consider the series (for n 7 from reference [24]).…”

mentioning

confidence: 99%

Molecular structure and the occurrence of smectic A and smectic c phases

Jeu

1977

J. Phys. France

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“…Fifteen of these materials (12,13,16, 20-31), the 4alkyl-4'-alkoxy-a-chloro-franj-stilbenes, can be classified as belonging to several homologous series. Each one, however, exhibits an nmr spectrum which contains an identical absorption in the vinylic-aromatic region.…”

Section: Resultsmentioning

confidence: 99%