Sulphur chelates 33. Preparation, characterization and x-ray structure determination of (chloro)(pentane-2,4-dithionato)(triethylphosphine)nickel(II), Ni(SacSac)(PEt3)Cl, an asymmetric complex which displays fluxional behavior in solution on the NMR time scale

Abstract The tittle compound has been prepared and characterized spectroscopically and by single-crystal X-ray crystallography (refined to R 1 = 0.052, R w = 0.064 with 1837 data having I > 3σ(I)). The dithioacetylacetonate (SacSac) methyl groups are NMR equivalent at room temperature, but can be resolved at temperatures below 288 K. The compound crystallizes in the monoclinic space group P2 1 /n with a = 7.6107(3) A, b = 18.1466(28) A and c = 11.5270(5) A; β =98.459(3)°, V = 1574.12(25) A 3 , and Z = 4. The coordination about the nickel(II) is planar. Important nickelligand lengths are NiS ( trans Cl) 2.108(2) A, NiS ( trans P) 2.154(2) A, NiCl 2.206(2) A, NiP 2.232(2) A with angles SNiS 97.9(1)°, SNiCl 85.Cl 85.6(1)°, SNiP 91.4(1)° and ClNiP 85.2(1)°. Two of the triethylphosphine ethyl groups lie in a plane approximately normal to the rest of the molecule. The dithioacetylacetonate dimensions are similar to those in Ni(SacSac) 2 , although the chelate bite is smaller, and there may be some asymmetry in the CS bonding in Ni(SacSac)PEt 3 Cl. The molecules pack with their chelate rings approximately parallel.