Synthesis, characterization, crystal structure and liquid crystal studies of some symmetric naphthalene derivative molecules.

Abstract The synthesis of a series of symmetrical liquid crystals having naphthalene as the central rigid core and attached to long chain flexible 4′-alkoxybenzoate moiety at positions 2,6 - of the aromatic ring are reported. The mesophase behavior of the molecules was investigated using differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction studies. The studies reveal that the synthesized compounds exhibit stable enantiotropic mesophase of Smectic A (SmA) and Nematic (N) phase. The mesophase appearance is independent of the length of the alkyl chain. The molecular structure was determined by single crystal X-ray diffraction technique. The derivative with n- heptyloxy- flexible chain crystallizes under triclinic, P 1 ¯ space group with unit cell dimension a = 5.569(3) Å, b = 10.540(5) Å, c = 15.254(9) Å, α = 73.434(18)o, β = 80.807(19)o and γ = 82.02(2)o, V = 843.1(8) Å3. The dihedral angle between the naphthalene ring system and the benzoate moiety is 63.63(2)o. Graphical abstract Image Highlights • We have synthesized symmetric naphthalene centered molecules. • All the molecules were characterized by UV, IR, NMR analysis. • Liquid crystal property was evaluated by DSC and POM techniques. • Single crystal structure was confirmed by X-ray analysis. [ABSTRACT FROM AUTHOR]