Über krystallin‐flüssige Substanzen mit neuartigen Flügelgruppen vom Typus RO(CH 2 ) n O—

Molecular Crystals and Liquid Crystals

Bonde

2006

Two new mesogenic homologous series, each consisting of a methoxyethyl tail and a Schiff 's base central linkage, have been synthesized by condensing 2-methoxyethyl 4-aminobenzoate with different 4-n-alkoxybenzaldehydes or 4-n-alkoxybenzoyloxybenzaldehydes to give series I and series II, respectively, and their mesomorphic behavior was studied. In series I, 2-methoxy ethyl 4-(4 0 -n-alkoxybenzylidine)aminobenzoates, the n-butoxy derivative is nonmesogenic whereas higher homologues exhibit the SmA mesophase. In series II, 2-methoxyethyl 4 00 -[4-(4 0 -n-alkoxybenzoyloxy)benzylidene]aminobenzoates, all the twelve compounds synthesized exhibit mesomorphism. Methoxy to n-octyloxy derivatives exhibit an enantiotropic nematic mesophase. The smectic A mesophase commences from n-propoxy derivative and persists up to the last homologue synthesized. The mesomorphic properties of both series are compared with each other and also with the properties of other structurally related series to evaluate the effects of the ethoxyethyl chain on mesomorphism.

Section: Mesogenic Properties and Molecular Constitutionmentioning

confidence: 98%

“…Weygand et al [13] have reported mesogenic properties of an alkyl chain combining two ether functions as a terminal substituent. Chiang et al [14,15] studied the effect of ethoxyethoxyethoxy and butoxyethoxyethoxy tails on mesomorphism.…”

Section: Introductionmentioning

confidence: 99%

Mesogenic Schiff's Base Esters with a Methoxyethyl Tail

Molecular Crystals and Liquid Crystals

Bonde

2006

“…The molecules of series I and series B differ only at one terminus. The -OCH 3 terminal group of series I is replaced by -CH 3 in series B. Weygand et al 5 have studied an alkyl chain combining two ether functions, e.g. CH 3 OCH 2 O-.…”

Section: Series Ii: Methoxyethyl [4-(4′-n-alkoxybenzoyloxy) Phenylazomentioning

confidence: 99%

“…To distinguish these tail groups from branched alkyl groups, we will refer to them as broken alkyl terminal groups or chains. Weygand et al 5 have reported few compounds with alkyl chain combining two ether functions as a terminal substituent e.g. CH 3 OCH 2 O-.…”

Section: Introductionmentioning

confidence: 99%

Azomesogens with methoxyethyl tail: Synthesis and characterization

Pandya

2005

J Chem Sci

Two new mesogenic homologous series are synthesized from methoxyethyl 4-(4′-hydroxyphenylazo) benzoate. In series I the phenolic-OH group is alkylated, whereas in series II it is esterified with 4-n-alkoxybenzoyl group. In series I, all the nine members synthesized exhibit only enantiotropic smectic A mesophase. In series II, all the twelve homologues exhibit enantiotropic nematic mesophase. Smectic A mesophase appears from the n-decyloxy derivative as a enantiotropic phase and persists till the last n-hexadecyloxy member. The mesomorphic properties of both the series are compared with each other and also with the properties of other structurally related series to evaluate the effect of the methoxyethyl tail on mesomorphism.

“…To distinguish these from branched alkyl groups, we will refer to them as broken terminal alkyl chains. Weygand et al [17] have studied the alkyl chain CH 3 OCH 2 O-, which combines two ether functions as a terminal substituent. Rather few compounds have been examined, but the data shows that mesomorphic properties disappear entirely or compounds that have lower nematic thermal stabilities than the analogous compounds containing the CH 3 CH 2 CH 2 O-group.…”

Section: Introductionmentioning

confidence: 99%

Mesogenic cinnamates with a substituted ethyl terminal chain

Patel²

2007

Liquid Crystals

Two new mesogenic homologous series of liquid crystalline cinnamates with substituted ethyl tails, b-methoxyethyl [4-(49-n-alkoxycinnamoyloxy)benzoates (I) and b-chloroethyl [4-(49-nalkoxycinnamoyloxy)benzoates (II), have been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. In series I, lower-chain members exhibit nematic mesophase, middle members exhibit enantiotropic nematic as well as smectic A (SmA) mesophases, whereas higher members exhibit only an enantiotropic SmA mesophase. In series II, methoxy to n-butyloxy derivatives exhibit a monotropic nematic mesophase. The SmA mesophase commences from n-propyloxy derivative as monotropic and persists up to the last member synthesized. The mesomorphic properties of present series were compared with each other and with a structurally related mesogenic homologous series to evaluate the effects of substituted ethyl tail and cinnamoyloxy central linkage on mesomorphism.