title: Synthesis and liquid crystalline properties of new diols containing azomethine groups.
abstract: A series of new mesogenic azomethine diols were successfully synthesized by condensation reactions between various chloroalkanols and N,N'-bis(4-hydroxy)-benzylidene-o-toluidine (1). The structures of these compounds were confirmed by CHN, FT-IR, (1)H-NMR, and (13)C-NMR spectrophotometer. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC) and polarizing optical microscope (POM). 4,4'-di(4-Hydroxybutoxy)-N-benzylidine-o-tolidine (2a) does not exhibit liquid crystalline properties. A nematic texture was observed for mesogenic diols 2b, and 2d, whereas the diol 2c exhibits a smectic mesophase. The increase of terminal alkyl chain in these mesogenic diols leads to a decrease in the transition temperature.
authors.affiliation: School of Industrial Technology, University Sains Malaysia, 11800 Penang, Malaysia. issam@usm.my
authors.forename: Issam Ahmed
authors.initials: IA
authors.lastname: Mohammed
authors.forename: Govindarajan
authors.initials: G
authors.lastname: Sankar
authors.forename: Melati
authors.initials: M
authors.lastname: Khairuddean
authors.forename: Abu Bakar
authors.initials: AB
authors.lastname: Mohamad
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis*; D001391:Azo Compounds / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D050866:Liquid Crystals / Q000737:chemistry*; D015394:Molecular Structure; D044367:Phase Transition; D013882:Thiosemicarbazones / Q000737:chemistry*; D044366:Transition Temperature
chemical_list: D000438:Alcohols; D001391:Azo Compounds; D013882:Thiosemicarbazones; C512188:azomethine