Der Pharma Chemica
Journal for Medicinal Chemistry, Pharmaceutical Chemistry, Pharmaceutical Sciences and Computational Chemistry


Synthesis and Evaluation of Liquid Crystal Behavior of a Novel Homologous Series :4-(4′-n-alkoxy benzoyloxy) –4”-Nitro Benzyl Benzoates

Author(s): Patel J. M. and Chauhan M. L.

A Novel homologous series of mesogens have been synthesized and studied with a views to understand and establish the relations between molecular structure and liquid crystal properties of a substance. Totally eleven members of series synthesized. Mesogenic behaviors commences from C5 member of a series and continued up to C16 member. The rest of the members C1 to C4 are nonmesogenic. Mesogenic homologues ( C5 to C16) are enantiotropically nematogenic without exhibition of smectic property. Textures of nematic phase are threaded or schlieren. Transition temperatures were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Analytical, spectral and thermal data confirms the molecular structures of homologues. Thermal stability for nematic is 224.5 ºC. Mesomorphic phase length range from 6.0 ºC to 22.0 ºC. Cr-I/N and N-I transition curves of a phase diagram behave in normal manner from C1 to C12 members and then higher members C14 and C16 deviated from normal behaviour. Mesogenic properties of present novel ester series are compared with the structurally similar series. Odd-even effect is observed for the N-I transition curve. Thus present series is nematogenic whose mesogenic transition temperatures vary between 185 ºC and 238 ºC. The present novel series is a middle ordered melting type and nematogenic, without exhibition of smectogenic character.