Activation of Dinitrogen-Derived Hafnium Nitrides for Nucleophilic N-C Bond Formation with a Terminal Isocyanate

摘要

Synthetic methods for the assembly of nitrogen-carbon bonds are of fundamental and practical importance given the prevalence of this linkage in amino acids, pharmaceuticals. agrochemicals, and polymers. Because of its high atmospheric abundance and non-toxicity, molecular nitrogen is an attractive synthon for the construction of N-C bonds if the kinetic and thermodynamic barriers associated with N2 reduction can be surmounted. Inspired by reports by Sobota and Fryzuk, our laboratory has been exploring "ligand-induced N2 cleavage", whereby a reducing transition metal is combined with an incoming ligand to supply the requisite six electrons to cleave the N≡N bond. With strongly activated zirconocene and hafnocene dinitrogen complexes, this approach has proven to be a general method for nitrogen-carbon bond formation using carbon monoxide as the incoming ligand.