THE PREPARATION OF SOME THIOSEMICARBAZONES AND THEIR COPPER COMPLEXES

Abstract

Reactions of N- and S-substituted thiosemicarbazones with Cu(I) have been examined. No complexes are formed when the S atom is substituted and(or) when the N2 hydrogen atom is replaced by Me. 4,4-Dimethyl derivatives not only give the usual 1:1 complexes, but also 2:1 complexes (2 thiosemicarbazones to 1 copper) in which copper has been oxidized to Cu(II). Reactions of thiosemicarbazones with Cu(II) give 1:1, 2:1, and probably a mixture which corresponds to 2:3 complexes. A discussion on the possible structures for the 1:1 complexes is given and they are best represented as polymers, the metal being bonded to the sulphur and to a nitrogen atom of the thioseraicarbazide portion of the molecule. Infrared spectra of these compounds have been examined, particularly in the 1100 cm−1 region where a strong to medium band disappears in going from thiosemicarbazones to copper complexes. It is suggested that this band is due to the C=S vibration.