Synthesis, mesomorphic and gelation properties of 7-alkoxycoumarin-3-carbonyl hydrazine

A series of coumarin derivatives, 7-alkoxycoumarin-3-carbonyl hydrazine (nCCH), which possessed a hydrazine moiety at the end of the molecule was prepared and was characterised by infrared and 1H-nuclear magnetic resonance spectra, electrospray ionisation-mass spectrometry and elemental analysis. All the compounds exhibited enantiotropic mesophases with temperature domains of 67–82°C and 46–82°C on heating and cooling processes, as well as favourable gelability to kinds of organic solvents. The effect of the length of the alkoxy chain on mesomorphic and gelation properties was discussed. The studies revealed that hydrogen bonding between the nCCH molecules was one of the main driving forces for the formation of the gel and thermotropic mesophases.