Natural Abundance ¹⁵N and ¹³C CP/MAS NMR of Dialkyldithiocarbamate Compounds with Ni(II) and Zn(II)

Abstract

Different symmetrically substituted and cyclic dialkydithiocarbamate (R=CH₃, C₂H₅, C₃H₇, i-C₃H₇, C₄H₉, i-C₄H₉ and R₂=(CH₂)₅, (CH₂)₆, (CH₂)₄O) compounds, such as tetraalkylthiuram disulfides, mononuclear nickel(II), binuclear zinc(II) and heteropolynuclear complexes and their adducts (both non-solvated and solvated forms) with planar and non-planar N-donor organic bases, have been prepared and studied by means of natural abundance ¹³C and ¹⁵N CP/MAS NMR spectroscopy. Useful correlations between molecular structures and ¹³C and ¹⁵N chemical shifts in these compounds have been established and assignments to carbon and nitrogen sites in resolved molecular structures have been suggested. A combination of the mesomeric effect of dithiocarbamate groups and the (+)inductive effect of alkyl substituents at the nitrogen atoms has been discussed in interpretations of ¹³C and ¹⁵N chemical shifts of the studied compounds. A high sensitivity of ¹⁵N chemical shift to the subtle structural differences of both dithiocarbamate groups and N-donor molecules has been revealed. Several remarkable cases of conformational isomerism have been recognized for both dithiocarbamate complexes and their adducts.