| Abstract: | By Claisen type condensation of suitable ketones with dithiocarbonic esters meso-alkyl substituted thio-β-diketones were prepared and studied in their sensitivity towards metal ions. Real metal chelates could be obtained only with cobalt(III) and nickel(II). The compounds of lead(II), cadmium(II), zinc(II), copper(I), mercury(II), silver(I), palladium(II), platinum(II) and rhodium(III) show an unchelated carbonyl group in the IR spectrum and are therefore interpreted as mercaptides. From the IR spectra it is also concluded that the free ligands are predominantly existing in the enethiolic tautomeric form. The absence of visible absorption bands characteristic for usual thio-β-diketones and their metal chelates in the case of the meso-substituted derivates is discussed as a consequence of distortion of the molecule accompanied by a decrease of conjugation. |
