Synthesis and structures of dialkyl zirconium complexes with an [OSSO]-type bis(phenolate) ligand bearing a trans-1,2-cyclooctanediylbis(thio) unit

Dimethyl and bis[(trimethylsilyl)methyl] zirconium complexes ([OSSO]ZrR2) [4, R = Me; 5, R = CH2SiMe3] having [OSSO]-type bis(phenolato) ligand 1 based on the trans-1,2-cyclooctanediylbis(thio) core have been synthesized by the reactions of the corresponding dichloro zirconium complex 3 with 2 equiv. of MeMgBr and Me3SiCH2MgCl, respectively, in Et2O/toluene at −78 °C. The molecular structures of these complexes 3–5 were characterized by NMR spectroscopy, elemental analyses, and X-ray crystallography. 1H and 13C NMR data of complexes 3–5 exhibited that they took the C2-symmetry in solution in the NMR time scale. In the crystal structures of 3–5, each zirconium center lies at the center of a distorted octahedral coordination sphere with cis sulfur atoms and trans oxygen atoms, which adopts a cis-α [(Λ∗,S∗,S∗)] configuration.