Synthesis, structure, and dynamic properties of W(S) (PhC2Ph)(S2CNEt2)2, a sulfidotungsten(IV) alkyne complex

Article abstract of DOI:10.1021/om00123a022

Synthesis of W(S)(PhC₂Ph)(S₂CNEt₂)₂ (1) has been accomplished by oxidation of W(CO)-(PhC₂Ph)(S₂CNEt₂)₂ with cyclohexene sulfide. The molecular structure of 1 has been determined by a single-crystal X-ray diffraction study. The crystals were found to be monoclinic of space group P2₁/n with a = 10.175 (7) ?, b = 14.165 (6) ?, c = 19.279 (39) ?, and β= 94.97 (2)°. The unit cell contains one independent molecule per asymmetric unit; the structure was refined to R = 0.064 and R_w = 0.079 with the use of 3623 reflections with I > 3σ(I). The molecular geometry can be described as a distorted octahedron. The alkyne ligand is cis to the terminal sulfide with the C₂ unit nearly perpendicular to the W=S moiety. A rearrangement of the chelating ligands, perhaps via dissociation of the dithiocarbamate sulfur trans to the terminal sulfide to form a fluxional five-coordinate intermediate, is compatible with dynamic NMR data obtained for 1. A related minor product, W(S)(PhC₂Ph)(S₂CNEt₂)(SCNEt₂), is believed to result from internal oxidative addition of one of the dithiocarbamate C-S bonds to the W(II) center of the W(CO)(PhC₂Ph)(S₂CNEt₂)₂ reagent.