Michael H. Quick

Synthesis and cleavage reactions of thiocarbonyl-bridged Cp2Fe2(CO)3CS, and preparation of the carbene complexes CpFe(CO)C(N2C2H6)SnPh3 and [CpFe(CO)2C(OMe)2]PF6

The thiocarbonyl-bridged complex Cp2Fe2(CO)3CS is obtained by the reaction of CpFe(CO)2− and (PhO)2CS in THF. Infrared and NMR spectra show that the compound exists in solution in interconverting cis and trans forms, but that the isomerization occurs more slowly than for the carbonyl analog [CpFe(CO)2]2. Most reagents which cleave [CpFe(CO)2]2, such as Br2, HgCl2, and O2/HBF4, do not give simple cleavage reactions with Cp2Fe2(CO)3CS. Reductive cleavage of Cp2Fe2(CO)3CS with Na(Hg) gives the thiocarbonyl anion CpFe(CO)(CS)−, which reacts with Ph3SnCl to form CpFe(CO)(CS)SnPh3. Methylamine reacts with CpFe(CO)(CS)SnPh3 to give CpFe(CO)(CNMe)SnPh3, while ethylenediamine gives the carbene complexes CpFe(CO)C(N2C2H6)SnPh3. The preparation of another new carbene complex, [CpFe(CO)2C(OMe)2]PF6, is also described.

Crystal and molecular structure of an organic thiocyanate complex: (CH3SCN)Cr(CO)5

Abstract The molecular structure of (CH3SCN)Cr(CO)5 has been determined by single crystal X-ray diffraction techniques. It crystallizes in the monoclinic space group P21/n with a  6.572(1), b  12.034(3), c  13.783(3) A,β  96.48(3)° with four molecules per cell. The structure was refined by the full matrix least squares techniques to a final crystallographic discrepancy factor R  Σ∥Fo∥  ∥Fc∥/Σ∥Fo∥ of 0.038 based on 1513 unique observed reflections (I > 3σ(I)). The methyl thiocyanate ligand was found to be coordinated via the nitrogen atom with structural parameters essentially identical to those of the free, gaseous CH3SCN. The coordination geometry around the chromium atom is octahedral with the CrC distance (1.831(4) A) to the trans CO ligand shorter than those (1.905(4) A, average) to the cis CO groups.