THIOCYANATES - 1 - N-H(N)...S BONDING IN TETRAHEDRAL [ZN(NCS)(2)L](0)COMPLEXES (L = MEXH2-XN(CH2)(2)NH2-YMEY, X, Y = 0-2)

The crystal structures of uncharged tetrahedral dithiocyanato zinc com plexes with N-methylated ethyienediamines have been determined with a view to a study of intermolecular hydrogen-bonding interactions in the se compounds. It is found that the H(N) hydrogen atoms are exhaustivel y engaged in N-H(N)... S bonds. The majority of these bonds are branch ed (bifurcated or trifurcated), and the hydrogen-bond systems they for m all contain one of the two characteristic primitive core motifs: eit her a discrete centrosymmetric [... S ... H ...](2) dimer or an infini te [... S ... H ...](infinity) helix about a 2(1) or pseudo-2(1) axis. The hydrogen bonding is analyzed in detail, with particular attention to the existence of correlations between the N-H(N)-S angles and the H(N)... S distances as well as between the corresponding N-H(N)-S/H(N) ... S pairs in the bifurcated N-H(N)... 2S bonds.