SOLVENT EFFECTS ON THE NITROGEN NMR SHIELDINGS OF CYANAMIDE AND N,N-DIMETHYL CYANAMIDE

High precision N-14 NMR measurements of solvent induced nitrogen shiel ding variations in both the NR(2) and cyano moieties of cyanamide and of N,N-dimethylcyanamide are reported. The solvent induced shielding c hanges are much larger for the cyano, than for the NR(2) groups. The N Me(2) group has a nitrogen shielding which is almost invariant to choi ce of solvent. Solvent effects on the cyano groups of the compounds st udied closely match those observed for simple alkyl cyanides. Overall analysis of the nitrogen shielding data favours a highly non-planar ge ometry for the compounds studied and no significant pi electron conjug ation between the NR(2) and the cyano groups.