Influence of bromoalkyloxy side chain on mesomorphic behavior in heterocyclic 7-(4-bromoalkyloxy)-3-(4'-decyloxyphenyl)-4H-1 -benzopyran-4-ones

A new homologous series of isoflavone-based ethers, 7-(4-bromoalkyloxy)-3-(4'-decyloxyphenyl)-4H-1-benzopyran-4-ones were synthesized and characterized. The mesomorphic properties of all homologues were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Enantiotropic smectic A (SmA) phase was observed for all homologues. The structure-property study was carried out by comparing the mesomorphic behavior of the homologues with those previously reported analogues. The bromine atom from the alkyloxy side chain of the benzene ring fused to the heterocyclic moiety was found to be capable of changing the mesomorphic properties.