An alkyne derivative of an organoimido molybdenum(IV) complex: molecular structure of the acetone hemi-solvate of bis(diethyldithiocarbamato)-dimethylacetylenedicarboxylate( p-tolylimido)molybdenum(IV), Mo(Ntol)(DMAC)-(S 2CNEt 2) 2· 1/2Me 2CO

Abstract

The molecular structure of the dimethylacetylenedicarboxylate adduct of bis(diethyldithiocarbamato)- ( p-t olylimid o)molybdenum(IV), Mo(Ntol)(DMAC)- (S 2CNEt 2) 2, is described. The complex represents a rare example of an unsaturated organic molecule ligated to an organoimido species. Crystals suitable for X-ray diffraction were obtained as the acetone hemi-solvate. The complex crystallizes in space group P2 1/ c with the following parameters: a = 17.680(3), b = 8.860(1), c = 20.497(3) Å, β = 106.97(1)°, Z = 4. Least-squares refinement based on all 4039 unique intensities converged to R = 0.042 and R w = 0.054. The complex displays a distorted pentagonal bi-pyramidal structure with the imido ligand occupying an apical position and the alkyne lying in the pentagonal plane. Analysis of the metrical parameters of the complex leads to the conclusion that the alkyne successfully contributes a slight amount of pi-electron density to the Mo atom in competition with the imido ligand.