Crystal and molecular structure of zinc(II) and cobalt(II) diethyldithiophosphinates

Abstract

Zinc(II) and cobalt(II) diethyldithiophosphinates are isostructural in the solid state. The crystal structure of the zinc(II) derivative, Zn(Et₂PS₂)₂, has been determined from three-dimensional X-ray diffraction data and solved by Buerger minimum function and Fourier methods. Anisotropic block-diagonal least-squares refinement led to a final R of 0·106 for 3956 independent reflexions. Crystals are monoclinic, space group P2₁, with cell dimensions: a= 10·67, b= 31·93, c= 12·50 Å, β= 126·7°, Z= 8. The crystal consists of discrete dimeric molecules with distorted-tetrahedral zinc atoms double-bridged by two dithiophosphinate groups forming an eight-membered ring. The co-ordination polyhedron of the zinc atoms is completed by dithiophosphinate groups, which behave as chelate ligands and form planar four-membered rings. If the ethyl groups are neglected the dimers have an approximate C₂ symmetry. The bond lengths and angles in the eight-membered rings are in the ranges: Zn–S, 2·302–2·382(8); P–S, 1·99–2·06(1)Å; S–Zn–S, 119·3–122·4(3); S–P–S, 115·3–116·7(4); and Zn–S–P, 99·2–106·6(4)°; and in the four-membered cycles are in the ranges: Zn–S, 2·365–2·509(8); P–S, 1·99–2·06(1)Å; S–Zn–S, 85·3–86·3(3); S–P–S, 108·7–110·4(5); and Zn–S–P, 80·3–83·3(4)°.