Solid state structure and reactivity in solution. II. The crystal and molecular structure of (2,2,7,7-tetramethyl-3,6-dithiaoctane)-tetracarbonylchromium(0)

Abstract

The crystal and molecular structure of the title compound, (DTO)Cr(CO) 4, has been determined by single-crystal X-ray diffraction techniques. The crystals are monoclinic, a = 9.583(4), b = 13.399(5) and c = 14.809(8) Å, β = 101.62(4)°, space group P2 1/n, d (calc. z = 4) = 1.32 g/cm 3. The structure was solved by MULTAN and refined by full-matrix least-squares methods to R = 0.05 using 2274 reflections measured on a four circle diffractometer with Mo-Kα radiation. The coordination about the central chromium atom is a distorted octahedron, the greatest deviations from ideal geometry being the angle S1CrS2, 80.6(1)°, and the angle between the two mutually trans carbonyls, 169.8(2)°. Mean metal-ligand bond lenghts are CrS = 2.437(1), CrC( cis) = 1.863(5) and CrC( trans) = 1.820(5) Å. The influence of the two bulky t-butyl substituents, bonded to S, on the octahedral geometry about Cr, and the possible influence of this molecular distortion on the reactivity of the complex via displacement of the chelating ligand by Lewis bases are discussed.