Zinc quinolates through styryl substitution in 2-position via acetoxy exchange reaction

Abstract: 2-Methyl-8-quinolinol reacted with salicylaldehyde to give the corresponding substituted 2-styryl-8-quinolinol. Two schemes were adopted in order to prepare zinc quinolates complex through styryl substitution in 2-position. In , four steps were used including hydrolysis of acetoxy, and single crystal of product of this step was acquired. For , acetoxy exchange reaction was directly used to give Zn complex from the styryl derivative a and Zn(OAc)2 in the presence of ethanol and triethylamine, which is a more facile synthesis method of zinc quinolates through styryl substitution in 2-position. The spectroscopic, thermal and optical properties of Zn complex were investigated. The thermal stability of Zn complex was higher than that of styryl derivative a. The residue yield at 800°C in N2 for Zn complex was 64.3% whereas that for styryl derivative a was almost zero. Solutions of Zn complex in THF emitted yellow light with photoluminescence (PL) maximum at 551nm, which is considerably red-shifted relative to Znq2 (535nm) and Zn(2-Meq)2 (515nm). The ground- and excited-state geometries, charge distributions, and excitation energies of Zn complex were evaluated by ab initio calculations. [Copyright &y& Elsevier]