Metal carbonyls of telluroether formed by the oxygen atom transfer reaction to M(CO)₆ (M = Mo, W) in the presence of (p-CH₃OC₆H₄)₂TeO and relative kinetic investigation

A new synthetic process is reported for the preparation of two substituted metal carbonyls, (p-CH₃OC₆H₄)₂TeM(CO)₅ (M = Mo, W). In the presence of (p-CH₃OC₆H₄)₂TeO as O atom transfer reagent in tetrahydrofuran solvent, a CO ligand is replaced by telluroether when M(CO)₆ (M = Mo, W) is reacted with (p-CH₃OC₆H₄)₂TeO under very mild experimental conditions (r.t.). The products were characterized by elemental analysis, mass, IR and ¹H NMR spectroscopies. The spectra suggest that the coordination geometry is distorted from a regular octahedral structure due to an asymmetrical bulky telluroether ligand on the metal atom. Kinetics of these reactions of M(CO)₆ with (p-CH₃OC₆H₄)₂TeO show the reactions are first order in the concentration of M(CO)₆ and of Te oxide. The rates of reaction decrease in the order W(CO)₆>Mo(CO)₆>Cr(CO)₆, and the results obtained are discussed in term of a presumed mechanism.