Crystal and molecular structure of tris-(O-isopropylxanthato)-chromium(III)

The title compound has been synthesized by the reaction of CrCl₃6H₂O with K{S₂COCH(CH₃)₂} in a 13 molar ratio in an aqueous medium. It has been characterized by elemental analysis and IR spectral studies. Crystals of Cr{S₂COCH(CH₃)₂}₃ are monoclinic, space group P2₁/n witha=10.002(2),b=10.973(1),c=18.961(6) Å,=91.78(2)°,V=2079.9 ų,Z=4,D _calc=1.46 g cm^–3, monochromatic radiation (Mo-K), =0.71069 Å,=11.2 cm^–1,F(0 0 0)=948,T=295K, finalR=0.0320 for 2641 reflections. The environment of the chromium atom is based on an octahedral geometry having six sulfur donor atoms from three symmetrically chelated ligands with average distances: Cr-S=2.396(9) Å, C-S=1.690(3) Å and C-O=1.315(3) Å. The bond distance between oxygen atom and the carbon atom of the isopropyl group (O-C_av=1.478(4) Å) suggests that the form –S ₂ ^(–) C=O⁽⁺⁾CH(CH₃)₂ contributes significantly to the structure of the isopropyl group.