Crystal structure of trans-dithiocyanatotetrakis-(NN′- diethylthiourea)-nickel(II)

The structure of the complex Ni(NCS)₂[S:C(NHEt) ₂]₄ has been determined by three-dimensional X-ray diffraction at 293°K. It forms crystals of space group P2₁/c with a unit cell of dimensions a = 11·14, b = 17·26, c = 9·64 Å, and β = 100·6°, containing two centrosymmetric molecules. The atoms were located from three-dimensional Patterson and difference Fourier maps, and the structure was refined by full-matrix least-squares to R = 0·095 for 1360 measured independent reflections. The ligands are in an octahedral arrangement, with significant deviations from 90°in the angles subtended at the nickel atom, the angles being 88·2, 83·9, and 86·4°, the bond lengths are Ni-N(NCS) 1·993, Ni-S 2·493, and 2·562 Å, average values for lengths in SC(NHEt)₂ are C=S 1·733, C-N 1·323, N-CH₂ 1·473, CH₂-CH₂ 1·558 Å, not significantly different from those found in other co-ordinated and free thioureas and substituted thioureas; in NCS, N-C 1·169 and C-S 1·636, are values very like those found in similar thiocyanates. There is evidence of the presence of a network of intra- and inter-molecular N-H ⋯ S hydrogen-bonds.