130286-00-9Relevant academic research and scientific papers
Novel Cinnamate Esters - Synthesis and Mesomorphic Properties in Relation to Molecular Structure
Patel, Brijesh H.,Doshi
, p. 42 - 51 (2014)
A novel homologous series 4-[4′-n-alkoxy cinnamoyloxy] benzyl cinnamates consisting of 11 homologs was synthesized and studied with a view to understanding and establishing the relation between molecular structure and mesomorphic behavior of a substance. Mesomorphic behavior of the series commences from the third homolog and then continues until the last hexadecyloxy homolog. The first and second members of a series are non-mesomorphic. Nematogenic mesophase formation is observed from the propoxy homolog to the hexadecyloxy homolog, but the smectogenic mesophase formation is observed from the hexyloxy homolog to the tetradecyloxy homolog. All mesomorphic transitions are enantiotropic in nature. Transition temperatures were determined by an optical polarizing microscopy equipped with a heating stage. The textures of the nematic mesophase are threaded or Schlieren in type and that of the smectic mesophases are focal conic fan shaped of the smectic A or smectic C type. A phase diagram of the series shows a normal behavior of the transition curves with a minor abnormality of the last three homologs for the nematic-isotropic transition curve. The average thermal stability for smectic and nematic mesophases is 176.0°C and 219.3°C, respectively. Analytical and spectral data agree with the molecular structures of homologs. Mesomorphic phase length varies between 22°C and 76°C. Smectic phase length varies from 6°C to 33°C and nematic phase length varies from 22°C to 54°C. Thus, the novel present series is predominantly nematogenic and partly smectogenic. Mesomorphic properties of the novel series are compared with structurally similar other known homologous series.
Synthesis and liquid crystalline properties of novel ethylene derivatives
Chauhan,Shah,Doshi
, p. 36 - 43 (2013/08/23)
A novel homologous series of liquid crystals, viz., α-4-[4′-n- alkoxy cinnamoyloxy] benzoyl-β-4″-chloro phenyl ethylenes, has been synthesized. The series consists of twelve homologs. The methyl to butyl derivatives are not liquid crystalline and the rest of the homologs are enantiotropic liquid crystals. The octyl to dodecyl derivatives of the series are enantiotropically smectogenic in addition to nematogenic in character, but the pentyl, hexyl, heptyl tetradecyl, and hexadecyl homolog derivatives of the series are only nematogenic without the exhibition of a smectic phase. The transition temperatures of the novel substances were determined by optical polarizing microscopy equipped with a heating stage. A plot of transition temperatures versus the number of carbon atoms present in the n-alkoxy terminal chain represents the phase behavior of the series. An odd-even effect is observed for the nematic-isotropic transition curve. The textures of the nematic phase are of a threaded or Schlieren type and those of the smectic A and smectic C phases are typical. Analytical and spectral data agree with the molecular structures. The smectic and nematic thermal stabilities are 132.6°C and 156.7°C, respectively. The smectic phase commences from the octyloxy homolog. Smectogenic phase lengths vary from 26°C to 33°C and the nematogenic phase lengths vary from 6°C to 70°C. The series is predominantly nematogenic and partly smectogenic with considerable mesophase length and a middle-ordered melting type. The liquid crystal properties of the present series are compared with structurally similar homologous series.
Synthesis of novel mesomorphic homologous series: α-4-[-4′-n- alkoxy cinnamoyloxy] phenyl-β3″ nitrobenzoyl ethylenes
Chaudhari,Doshi
, p. 49 - 56 (2013/02/22)
Eleven novel mesomorphic homologues were synthesized and evaluated for their mesomorphic properties. The methoxy to n-butyloxy homologues are nonmesomorphic, while the other homologues are enantiotropic mesomorphic. The n-pentyloxy, n-hexyloxy, and n-octyloxy homologues are polymesomorphic, i.e., smectic and nematic mesophases are exhibited enantiotropically. Only the nematic mesophase is exhibited by the n-decyloxy to n-hexadecyloxy homologues. Analytical data confirm the structure and textures of molecules. The nematic mesophase shows a threaded-type texture, and that of smectic phase is of smectic A type. The mesomorphic properties are compared with a structurally similar homologous series. The average thermal stability for the smectic and nematic mesophases is 154.6C and 163.8C, respectively, as observed through optical polarizing microscope with heating stage. Copyright Taylor & Francis Group, LLC.
Mesogenic Homologous Series : 4-Isopropoxyphenyl-4′-n-alkoxycinnamates and Binary Systems Comprising the Homologues of this Series
Vora,Vyas
, p. 507 - 511 (2007/10/03)
Twelve members of the homologous series-A have been synthesised. First two members are non-mesogenic. The nematic mesophase commences as a monotropic phase from n-propoxy derivative. equation presented Series-A (where n = 1 to 16) n-Propoxy to n-heptyloxy derivatives exhibit only nematic phase. n-Octyloxy and n-decyloxy derivatives exhibit smectic and nematic phases. n-Dodecyloxy to n-hexadecyloxy derivatives exhibit only smectic phase. Seven binary systems comprised of homologues of series-A have been studied. The non-mesogens induce mesomorphism in a few binary systems. Other binary systems, where both the components are mesogens, exhibit normal behaviour of mesogenic binary systems. Results indicate that eventhough homologues of series-A contain branched alkyl chain, the binary systems do not exhibit pronounced decrease in melting behaviour.
