STRUCTURES OF (SULFUR DIOXIDE)TRIS(TRIPHENYLPHOSPHINE)NICKEL(O), NI(SO2)(PPH3)3, AND BIS(SULFUR DIOXIDE)BIS(TRIPHENYLPHOSPHINE)NICKEL(O), NI(SO2)2(PPH3)2

The structures of Ni(SO2)(PPh3)3 (I) and Ni(SO2)2(PPh3)2 (II) have been determined by three-dimensional X-ray diffraction techniques. Complex I crystallized in the space group P21/n with lattice constants of a = 11.39 (2) Å, b = 31.01 (3) Å, c = 13.11 (2) Å, and β = 95.34 (9)° and was refined to an unweighted R value of 0.080 for 3635 reflections for which I ≥ 2σ (I). Complex II crystallized in the space group P21/c with lattice constants of a = 19.427 (6) Å, b = 10.370 (6) Å, c = 17.702 (6) Å, β = 112.62 (2)°, and Z = 4 (Mo Kα1 radiation, λ 0.7093 Å) and was refined to an unweighted R value of 0.078 for 1483 reflections for which I ≥ 3σ(I). The sulfur dioxide groups are S bonded in both complexes and are coplanar with their respective Ni-S bonds. For complex II, the two SO2 groups are nearly coplanar with each other, the dihedral angle between them being 23.5°. The angles about the nickel atoms are nearly tetrahedral in both complexes with NiS distances of 2.06 (1) and 2.08 (1) Å for II and 2.038 (4) A for I. Complex I exhibits an average S-O distance of 1.448 (5) Å and an O-S-O angle of 113.4 (4)° while the values for II are 1.39 (1) A and 115.5 (1)°. The significance of these structures relative to the isoelectronic complexes Pt(SO2)(PPh3)3 and Pt(SO2)2(PPh3)2, which exhibit pyramidal geometry at the sulfur atom, is discussed. © 1979, American Chemical Society. All rights reserved.