Structure of (1,2-diaminoethane) (1-[[2-[(2-aminoethyl)imino]propyl]thio]-2-propanone)nickel(II) nitrate

A single crystal X-ray investigation of the purple nickel (II) complex NiL(en)](NO₃)2, produced by condensation of 1,2-diaminoethane (en) with the thiodiketone S(CH₂COCH₃)2 in the presence of nickel (II) nitrate (L is NH₂(CH₂)₂N=C(CH₃)CH₂SCH₂COCH₃), shows that the metal ions are six coordinate. The new ligand L is tetradentate, with the N,N and S donor atoms arranged meridionally, and the coordination shell completed by the carbonyl oxygen atom of L and the nitrogen atoms of 1,2-diaminoethane. Metal-ligand bond distances are Ni-N: 2.08 av. (en), 2.10 and 2.05 (NH₂ and N=C respectively of L); Ni-O, 2.16; Ni-S, 2.45 Å. There is considerable angular distortion from regular octahedral values of the bond angles at nickel. The crystals are monoclinic,P2₁/c (No. 14),a=12.433(2),b=11.709(1),c=13.150(2) Å,=103.93(1)°,V _c=1858.2(4) ų. The structure was solved by the heavy-atom method and refined by full-matrix least squares to anR value of 0.055 for 3633 reflections.