N.M.R. studies of some chromium(III) dithiocarbamate complexes

The temperature dependence of the proton N.M.R. spectra of some simple tris(N,N-disubstituted dithiocarbamato)chromium(111) derivatives, [Cr(S2CNR2)3], has been studied in deuterochloroform solution over the range ? 60� to + 60�C. In these spectra, which are very broad, the N-CHn protons in certain cases exhibit a double peak unlike the iron(111) or manganese(111) complexes-probably a consequence of high energy barriers between the Δ and Δ enantiomers, the broadness of the spectra being ascribed to the lack of an appropriate relaxation mechanism. The spectra of a number of further iron(111) and manganese(111) derivatives are reported and the hyperfine coupling constants in the three series of complexes compared.