A physico-chemical study of the copper(II) chelates of 3-hydroxyphenylrhodanine. Its mixed-ligand chelate formation and conversion into a copper(II) dithiocarbamate chelate

Abstract

The highly coloured copper(II) chelates of 3-hydroxyphenylrhodanine [3-(3-hydroxyphenyl)-2-thioxo-1,3-thiazolidin-4-one] and (4,5-dibromo-3-hydroxyphenyl)rhodanine have been prepared and characterised by elemental analysis, i.r. spectroscopy, and magnetic susceptibility measurements. The 3-hydroxyphenylrhodanine chelate has been shown to be useful in the sensitive spectrophotometric determination of copper(II). E.s.r. measurements show that the chelate forms a tetrapyridine solvate in pyridine solution. Mixed-ligand chelates consisting of copper(II) and 3-hydroxyphenylrhodanine and an amino-acid such as threonine, or a polyamino-carboxylic acid such as ethylenediaminetetra-acetic acid, have also been prepared and characterised. Dissolution of these copper(II) chelates of rhodanine in chloroform leads to the formation of the dithiocarbamate chelates bis(N-chloroacetyl-N-3-hydroxyphenyldithiocarbamato) copper(II) and bis(N-chloroacetyl-N-4,5-dibromo-3-hydroxyphenyldithiocarbamato) copper (II).