Nucleophilic reactivity of a d0molybdenum oxo moiety

Abstract

The previously reported complexes [Mo(N^tBu)(O)(2,6-Me₂C₆H₃O)₂(py)] (1) and [Mo(N^tBu)(O)(2,6-ⁱPr₂C₆H₃O)₂(py)] (2) have been shown to contain a nucleophilic oxo ligand. The reaction of 2 and tert-butylacetyl chloride gave the novel complex [Mo(N^tBu)(2,6-ⁱPr₂C₆H₃O)₂(O₂CCH₂^tBu)Cl] (3) in 63% yield as the product of nucleophilic acyl substitution. Complex 1 undergoes a clean reaction with triflic anhydride to give the novel complex [{Mo(N^tBu)(2,6-Me₂C₆H₃O)₂}(μ-O)(μ-OTf)₂] (4) in 75% yield. Complex 4 appears to be formed from nucleophilic attack of the oxo ligand on triflic anhydride, followed by nucleophilic attack of a second oxo moiety on the cationic intermediate. The solid-state structures of 3 and 4 have been determined by X-ray crystallography. These are rare examples of nucleophilic oxo ligands bound to a d⁰ transition metal centre.