94706-53-3Relevant academic research and scientific papers
Conversion of a dithiocarbamate ligand to a thiocarboxamido ligand to form W(S)(PhC≡CPh)(S2CNEt2)(SCNEt2)
Brower, Douglas C.,Tonker, Teresa L.,Morrow, Janet R.,Rivers, David S.,Templeton, Joseph L.
, p. 1093 - 1097 (2008/10/08)
The W(IV) bis(dithiocarbamate) complexes W(S)(PhC≡CPh)(S2CNR2)2 (R = CH3, C2H5) lose one sulfur atom when treated with an equivalent of triethylphosphine at -78°C. The products W(S)(PhC≡ CPh)(SCNR2)(S2CNR2) contain a thiocarboxamido ligand in place of one dithiocarbamate. The molecular structure of the ethyl derivative was determined by a single-crystal X-ray diffraction study (monoclinic, P21/a; a = 16.927 (6) A?, b = 9.951 (3) A?, c = 17.669 (6) A?, β = 118.49 (3)°, and Z = 4; R = 0.078 and Rw = 0.064 for 1962 reflections with I > 3σ(I)). The carbenoid carbon of the thiocarboxamido ligand lies cis to the alkyne ligand in the plane defined by the metal-alkyne triangle. The orientation of the η2-SCNEt2 fragment allows the unique p orbital of the three-coordinate carbon to overlap with the lone filled dπ orbital of the roughly octahedral d2 tungsten(IV) ion. A dynamic process equilibrates the two dithiocarbamate alkyl substituents on the NMR time scale with an activation barrier of 15.9 kcal/mol. We suggest that this process is promoted by dechelation of the η2-thiocarboxamido sulfur to generate a fluxional five-coordinate intermediate.
Synthesis, structure, and dynamic properties of W(S) (PhC2Ph)(S2CNEt2)2, a sulfidotungsten(IV) alkyne complex
Morrow,Tonker,Templeton
, p. 745 - 750 (2008/10/08)
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 Rw = 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.
