Synthesis of SS′-bis(4′-benzo[15-crown-5])dithioglyoxime and its complexes with copper(II) nickel(II), cobalt(II), cobalt(III), palladium(II), platinum(II), and platinum(IV)

Abstract

SS′-Bis(4′-benzo[15-crown-5])dithioglyoxime (H₂L) has been prepared from 4′-mercaptobenzo[15-crown-5], anti-dichloroglyoxime, and sodium bicarbonate in ethanol. Nickel(II), palladium(II), platinum(II), copper(II), cobalt(II), and cobalt(III) complexes of H₂L have a metal–ligand ratio of 1:2 and the ligand co-ordinates through the two N atoms, as do most of the vic-dioximes. The complex [Pt(HL)₂Cl₂·4NaClO₄] forms six-membered chelate rings and co-ordinates through N and O atoms. [Co(HL)₂(PPh₃)Cl·4NaClO₄] and [Co(HL)₂(C₅H₅N)Cl·2NaClO₄] have been prepared with triphenylphosphine or pyridine and chloride as axial ligands. The ion-extraction properties of the Ni^II, Pd^II, and Pt^II complexes towards lithium, sodium, and potassium picrate from aqueous solution to dichloromethane have been measured. Extraction values, n.m.r., i.r., and u.v.–visible data are presented.