Synthesis and characterization of a crown ether substituted salicylaldimine and its complexes with copper(II), cobalt(II), nickel(II), and uranyl(VI)

Abstract

4'-(omega-Salicylaldiminoacetyl)benzo (15-crown-5) (LH) has been synthesized from 4'-(omega-aminoacetyl)benzo(15-crown-5) and salicylaldehyde. Complexes of this Schiff base with copper(II), nickel(II), cobalt(II), and uranyl(VI) have been prepared from the corresponding metal acetates and chlorides. Insertion of sodium ions into the crown ether-moiety has been accomplished by refluxing LH with sodium nitrate in ethanol. The complexation of this ligand with Cu(II), Ni(II), Co(II), and U(VI)O-2 was investigated by potentiometric titration; the results indicate that all of them afford products with a metal-ligand ratio of 1:2. The order of formation constants of the mononuclear complexes is Cu(II) > Co(II) > U(VI)O-2 > Ni(II).