No abstract

Formation of deuteriochloroform complexes with four series of N 1 ,N 1 -dimethylamidines (R x N᎐ ᎐ CR 1 NMe 2 ; 75 compounds) containing a variable substituent R x at the imino nitrogen atom has been studied by infrared spectroscopy. It is found that for complexed CDCl 3 molecules a new, additional C-D stretching band appears at lower frequencies. The changes in frequency of this band depend on the basicity of the amidine and correlate with the pK a values of complexing amidines, however for N 2 -alkyl and N 2 -aryl derivatives separate correlations are obtained. The slope of the correlation line depends on substituent R 1 at the amidino carbon atom, and for N 2 -aryl derivatives it increases with the increase of the volume of a substituent at the amidino carbon atom, whereas for N 2 -alkyl derivatives it decreases. The inverse order of the change of the slopes is attributed to the E-Z isomerism in amidines.