Synthesis, structural characterization and thermal studies of lanthanide complexes with Schiff base ligand N,N′-di-(4′-pentyloxybenzoate)-salicylidene-1,3-diaminopropane

Abstract

New mesogen Schiff base ligand N,N′-di-(4′-pentyloxybenzoate)salicylidene-1,3-diaminopropane [H₂L] was synthesized by the reaction of substituted 4-pentyloxy(4′-formyl-3′-hydroxy)-benzoate and 1,3-diaminopropane in 2:1 molar ratio. Four mononuclear lanthanide complexes of the type [Ln(H₂L)LCl] (Ln = LaIII, CeIII, SmIII and GdIII) were synthesized and characterized by ¹H,¹³CNMR, fourier transform infrared (FT-IR) spectroscopy, elemental analysis (C.H.N.O), gas chromotography-mass, magnetic susceptibility and molar conductivity. Thermal properties of the title compounds were studied using the thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) and optical polarizing microscopy (OPM). The ligand and coordination compounds exhibit liquid crystalline properties (smectic A).