Well-Defined Vanadium Organoazide Complexes and Their Conversion to Terminal Vanadium Imides: Structural Snapshots and Evidence for a Nitrene Capture Mechanism

We report the synthesis and structural characterization
of a family
of well-defined organoazide complexes supported by a three-fold-symmetric
pyrrolide scaffold and their conversion to the corresponding terminal
imido congeners. Kinetic measurements on a series of structurally
homologous but electronically distinct vanadium organoazide complexes
reveal that the azido-to-imido transformations proceed via a process
that is first-order in the metal complex and has a positive entropy
of activation. Further studies suggest that these reactions may involve
metal-mediated generation and capture of nitrene fragments.